HC11
Microcontrollers
freescale.com
M68HC11E Family
Data Sheet
M68HC11E
Rev. 5.1
07/2005
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 3
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© Freescale Semiconductor, Inc., 2005. All rights reserved.
MC68HC11E Family
Data Sheet
To provide the most up-to-date information, the revision of our documents on the World Wide Web will be
the most current. Your printed copy may be an earlier revision. To verify you have the latest information
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The following revision history table summarizes changes contained in this document. For your
convenience, the page number designators have been linked to the appropriate location.
Revision History
M68HC11E Family Data Sheet, Rev. 5.1
4Freescale Semiconductor
Revision History
Date Revision
Level Description Page
Number(s)
May, 2001 3.1 2.3.3.1 System Configuration Register — Addition to NOCOP bit description 44
Added 10.21 EPROM Characteristics 175
June, 2001 3.2 10.21 EPROM Characteristics — For clarity, addition to note 2 following the
table 175
December,
2001 3.3 7.7.2 Serial Communications Control Register 1 — SCCR1 bit 4 (M)
description corrected 110
July, 2002 4
10.7 MC68L11E9/E20 DC Electrical Characteristics — Title changed to
include the MC68L11E20 153
10.8 MC68L11E9/E20 Supply Currents and Power Dissipation — Title
changed to include the MC68L11E20 154
10.10 MC68L11E9/E20 Control Timing — Title changed to include the
MC68L11E20 157
10.12 MC68L11E9/E20 Peripheral Port Timing — Title changed to include the
MC68L11E20 163
10.14 MC68L11E9/E20 Analog-to-Digital Converter Characteristics — Title
changed to include the MC68L11E20 167
10.16 MC68L11E9/E20 Expansion Bus Timing Characteristics — Title
changed to include the MC68L11E20 169
10.18 MC68L11E9/E20 Serial Peirpheral Interface Characteristics — Title
changed to include the MC68L11E20 172
— Title changed to include the MC68L11E20 175
11.4 Extended Voltage Device Ordering Information (3.0 Vdc to 5.5 Vdc) —
Updated table to include MC68L1120 181
June, 2003 5
Format updated to current publications standards Throughout
1.4.6 Non-Maskable Interrupt (XIRQ/VPPE) — Added Caution note pertaining
to EPROM programming of the MC68HC711E9 device only. 23
6.4 Port C — Clarified description of DDRC[7:0] bits 100
10.21 EPROM Characteristics — Added note pertaining to EPROM
programming of the MC68HC711E9 device only. 175
July, 2005 5.1 Updated to meet Freescale identity guidelines. Throughout
M68HC11E Family Data Sheet, Rev. 5.1
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List of Chapters
Chapter 1 General Description. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13
Chapter 2 Operating Modes and On-Chip Memory . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .29
Chapter 3 Analog-to-Digital (A/D) Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57
Chapter 4 Central Processor Unit (CPU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .65
Chapter 5 Resets and Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79
Chapter 6 Parallel Input/Output (I/O) Ports . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .97
Chapter 7 Serial Communications Interface (SCI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105
Chapter 8 Serial Peripheral Interface (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .119
Chapter 9 Timing Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .127
Chapter 10 Electrical Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .149
Chapter 11 Ordering Information and Mechanical Specifications . . . . . . . . . . . . . . . . . .177
Appendix A Development Support . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .187
Appendix B EVBU Schematic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .191
AN1060 — M68HC11 Bootstrap Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .193
EB184 — Enabling the Security Feature on the MC68HC711E9 Devices
with PCbug11 on the M68HC711E9PGMR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .229
EB188 — Enabling the Security Feature on M68HC811E2 Devices
with PCbug11 on the M68HC711E9PGMR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .233
EB296 — Programming MC68HC711E9 Devices with PCbug11
and the M68HC11EVBU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .237
List of Chapters
M68HC11E Family Data Sheet, Rev. 5.1
6Freescale Semiconductor
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 7
Table of Contents
Chapter 1
General Description
1.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.2 Features. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13
1.3 Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.4 Pin Descriptions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14
1.4.1 VDD and VSS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21
1.4.2 RESET . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
1.4.3 Crystal Driver and External Clock Input (XTAL and EXTAL) . . . . . . . . . . . . . . . . . . . . . . . . 22
1.4.4 E-Clock Output (E) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
1.4.5 Interrupt Request (IRQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
1.4.6 Non-Maskable Interrupt (XIRQ/VPPE) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23
1.4.7 MODA and MODB (MODA/LIR and MODB/VSTBY) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.4.7.1 VRL and VRH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24
1.4.8 STRA/AS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.4.9 STRB/R/W . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.4.10 Port Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.4.10.1 Port A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 25
1.4.10.2 Port B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.4.10.3 Port C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
1.4.10.4 Port D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
1.4.10.5 Port E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28
Chapter 2
Operating Modes and On-Chip Memory
2.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.2 Operating Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.2.1 Single-Chip Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.2.2 Expanded Mode. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29
2.2.3 Test Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.2.4 Bootstrap Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30
2.3 Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31
2.3.1 RAM and Input/Output Mapping. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 39
2.3.2 Mode Selection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 40
2.3.3 System Initialization . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42
2.3.3.1 System Configuration Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
2.3.3.2 RAM and I/O Mapping Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45
2.3.3.3 System Configuration Options Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 46
2.4 EPROM/OTPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47
2.4.1 Programming an Individual EPROM Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
2.4.2 Programming the EPROM with Downloaded Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 48
Table of Contents
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2.4.3 EPROM and EEPROM Programming Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . 49
2.5 EEPROM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.5.1 EEPROM and CONFIG Programming and Erasure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.5.1.1 Block Protect Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 51
2.5.1.2 EPROM and EEPROM Programming Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . 53
2.5.1.3 EEPROM Bulk Erase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
2.5.1.4 EEPROM Row Erase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54
2.5.1.5 EEPROM Byte Erase . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
2.5.1.6 CONFIG Register Programming. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
2.5.2 EEPROM Security . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 55
Chapter 3
Analog-to-Digital (A/D) Converter
3.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.2 Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.2.1 Multiplexer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.2.2 Analog Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 57
3.2.3 Digital Control. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.2.4 Result Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.2.5 A/D Converter Clocks. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.2.6 Conversion Sequence . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
3.3 A/D Converter Power-Up and Clock Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 60
3.4 Conversion Process. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.5 Channel Assignments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.6 Single-Channel Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61
3.7 Multiple-Channel Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
3.8 Operation in Stop and Wait Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
3.9 A/D Control/Status Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 62
3.10 A/D Converter Result Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 64
Chapter 4
Central Processor Unit (CPU)
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.2 CPU Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 65
4.2.1 Accumulators A, B, and D . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4.2.2 Index Register X (IX) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4.2.3 Index Register Y (IY) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4.2.4 Stack Pointer (SP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 66
4.2.5 Program Counter (PC) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.2.6 Condition Code Register (CCR). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.2.6.1 Carry/Borrow (C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.2.6.2 Overflow (V) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.2.6.3 Zero (Z). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.2.6.4 Negative (N) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 68
4.2.6.5 Interrupt Mask (I) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.2.6.6 Half Carry (H) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.2.6.7 X Interrupt Mask (X) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.2.6.8 STOP Disable (S) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
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4.3 Data Types. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 69
4.4 Opcodes and Operands. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.5 Addressing Modes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.5.1 Immediate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.5.2 Direct . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70
4.5.3 Extended . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.5.4 Indexed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.5.5 Inherent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.5.6 Relative . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
4.6 Instruction Set . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71
Chapter 5
Resets and Interrupts
5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5.2 Resets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5.2.1 Power-On Reset (POR) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 79
5.2.2 External Reset (RESET) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
5.2.3 Computer Operating Properly (COP) Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80
5.2.4 Clock Monitor Reset. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 81
5.2.5 System Configuration Options Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 82
5.2.6 Configuration Control Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
5.3 Effects of Reset . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
5.3.1 Central Processor Unit (CPU) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83
5.3.2 Memory Map . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.3.3 Timer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.3.4 Real-Time Interrupt (RTI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.3.5 Pulse Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.3.6 Computer Operating Properly (COP) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.3.7 Serial Communications Interface (SCI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.3.8 Serial Peripheral Interface (SPI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 84
5.3.9 Analog-to-Digital (A/D) Converter . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.3.10 System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.4 Reset and Interrupt Priority . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 85
5.4.1 Highest Priority Interrupt and Miscellaneous Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86
5.5 Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 87
5.5.1 Interrupt Recognition and Register Stacking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 88
5.5.2 Non-Maskable Interrupt Request (XIRQ) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
5.5.3 Illegal Opcode Trap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 89
5.5.4 Software Interrupt (SWI) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
5.5.5 Maskable Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
5.5.6 Reset and Interrupt Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
5.6 Low-Power Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
5.6.1 Wait Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90
5.6.2 Stop Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95
Table of Contents
M68HC11E Family Data Sheet, Rev. 5.1
10 Freescale Semiconductor
Chapter 6
Parallel Input/Output (I/O) Ports
6.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 97
6.2 Port A . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 98
6.3 Port B . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
6.4 Port C. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 99
6.5 Port D. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 100
6.6 Port E . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
6.7 Handshake Protocol. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
6.8 Parallel I/O Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 102
Chapter 7
Serial Communications Interface (SCI)
7.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
7.2 Data Format . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
7.3 Transmit Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 105
7.4 Receive Operation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7.5 Wakeup Feature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7.5.1 Idle-Line Wakeup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107
7.5.2 Address-Mark Wakeup. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
7.6 SCI Error Detection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
7.7 SCI Registers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 109
7.7.1 Serial Communications Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
7.7.2 Serial Communications Control Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110
7.7.3 Serial Communications Control Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 111
7.7.4 Serial Communication Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 112
7.7.5 Baud Rate Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 113
7.8 Status Flags and Interrupts . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 116
7.9 Receiver Flags . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 117
Chapter 8
Serial Peripheral Interface (SPI)
8.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
8.2 Functional Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
8.3 SPI Transfer Formats. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 119
8.4 Clock Phase and Polarity Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 120
8.5 SPI Signals . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.5.1 Master In/Slave Out . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.5.2 Master Out/Slave In . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
8.5.3 Serial Clock . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
8.5.4 Slave Select . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
8.6 SPI System Errors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 122
8.7 SPI Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
8.7.1 Serial Peripheral Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 123
8.7.2 Serial Peripheral Status Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 124
8.7.3 Serial Peripheral Data I/O Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 11
Chapter 9
Timing Systems
9.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 127
9.2 Timer Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
9.3 Input Capture . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 129
9.3.1 Timer Control Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
9.3.2 Timer Input Capture Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
9.3.3 Timer Input Capture 4/Output Compare 5 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
9.4 Output Compare . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 133
9.4.1 Timer Output Compare Registers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 134
9.4.2 Timer Compare Force Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
9.4.3 Output Compare Mask Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
9.4.4 Output Compare Data Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 136
9.4.5 Timer Counter Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
9.4.6 Timer Control Register 1 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 137
9.4.7 Timer Interrupt Mask 1 Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
9.4.8 Timer Interrupt Flag 1 Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 138
9.4.9 Timer Interrupt Mask 2 Register. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 139
9.4.10 Timer Interrupt Flag Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
9.5 Real-Time Interrupt (RTI). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 140
9.5.1 Timer Interrupt Mask Register 2. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 141
9.5.2 Timer Interrupt Flag Register 2 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
9.5.3 Pulse Accumulator Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 142
9.6 Computer Operating Properly (COP) Watchdog Function. . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
9.7 Pulse Accumulator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
9.7.1 Pulse Accumulator Control Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 145
9.7.2 Pulse Accumulator Count Register . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
9.7.3 Pulse Accumulator Status and Interrupt Bits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 146
Chapter 10
Electrical Characteristics
10.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
10.2 Maximum Ratings for Standard and Extended Voltage Devices . . . . . . . . . . . . . . . . . . . . . . . 149
10.3 Functional Operating Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
10.4 Thermal Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 150
10.5 DC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 151
10.6 Supply Currents and Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 152
10.7 MC68L11E9/E20 DC Electrical Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 153
10.8 MC68L11E9/E20 Supply Currents and Power Dissipation . . . . . . . . . . . . . . . . . . . . . . . . . . . 154
10.9 Control Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 156
10.10 MC68L11E9/E20 Control Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 157
10.11 Peripheral Port Timing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 162
10.12 MC68L11E9/E20 Peripheral Port Timing. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 163
10.13 Analog-to-Digital Converter Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 166
10.14 MC68L11E9/E20 Analog-to-Digital Converter Characteristics . . . . . . . . . . . . . . . . . . . . . . . . 167
Table of Contents
M68HC11E Family Data Sheet, Rev. 5.1
12 Freescale Semiconductor
10.15 Expansion Bus Timing Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 168
10.16 MC68L11E9/E20 Expansion Bus Timing Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . 169
10.17 Serial Peripheral Interface Timing Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 171
10.18 MC68L11E9/E20 Serial Peirpheral Interface Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . 172
10.19 EEPROM Characteristics. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
10.20 MC68L11E9/E20 EEPROM Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
10.21 EPROM Characteristics . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 175
Chapter 11
Ordering Information and Mechanical Specifications
11.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
11.2 Standard Device Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
11.3 Custom ROM Device Ordering Information . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 179
11.4 Extended Voltage Device Ordering Information (3.0 Vdc to 5.5 Vdc) . . . . . . . . . . . . . . . . . . . 181
11.5 52-Pin Plastic-Leaded Chip Carrier (Case 778). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 182
11.6 52-Pin Windowed Ceramic-Leaded Chip Carrier (Case 778B) . . . . . . . . . . . . . . . . . . . . . . . . 183
11.7 64-Pin Quad Flat Pack (Case 840C) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 184
11.8 52-Pin Thin Quad Flat Pack (Case 848D) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 185
11.9 56-Pin Dual in-Line Package (Case 859). . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
11.10 48-Pin Plastic DIP (Case 767) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 186
Appendix A
Development Support
A.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
A.2 M68HC11 E-Series Development Tools . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
A.3 EVS — Evaluation System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
A.4 Modular Development System (MMDS11) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 188
A.5 SPGMR11 — Serial Programmer for M68HC11 MCUs. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 189
Appendix B
EVBU Schematic
AN1060 — M68HC11 Bootstrap Mode . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
EB184 — Enabling the Security Feature on the MC68HC711E9 Devices with PCbug11 on the
M68HC711E9PGMR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
EB188 — Enabling the Security Feature on M68HC811E2 Devices
with PCbug11 on the M68HC711E9PGMR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 233
EB296 — Programming MC68HC711E9 Devices with PCbug11
and the M68HC11EVBU . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 237
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 13
Chapter 1
General Description
1.1 Introduction
This document contains a detailed description of the M68HC11 E series of 8-bit microcontroller units
(MCUs). These MCUs all combine the M68HC11 central processor unit (CPU) with high-performance,
on-chip peripherals.
The E series is comprised of many devices with various configurations of:
• Random-access memory (RAM)
• Read-only memory (ROM)
• Erasable programmable read-only memory (EPROM)
• Electrically erasable programmable read-only memory (EEPROM)
• Several low-voltage devices are also available.
With the exception of a few minor differences, the operation of all E-series MCUs is identical. A fully static
design and high-density complementary metal-oxide semiconductor (HCMOS) fabrication process allow
the E-series devices to operate at frequencies from 3 MHz to dc with very low power consumption.
1.2 Features
Features of the E-series devices include:
• M68HC11 CPU
• Power-saving stop and wait modes
• Low-voltage devices available (3.0–5.5 Vdc)
• 0, 256, 512, or 768 bytes of on-chip RAM, data retained during standby
• 0, 12, or 20 Kbytes of on-chip ROM or EPROM
• 0, 512, or 2048 bytes of on-chip EEPROM with block protect for security
• 2048 bytes of EEPROM with selectable base address in the MC68HC811E2
• Asynchronous non-return-to-zero (NRZ) serial communications interface (SCI)
• Additional baud rates available on MC68HC(7)11E20
• Synchronous serial peripheral interface (SPI)
• 8-channel, 8-bit analog-to-digital (A/D) converter
• 16-bit timer system:
– Three input capture (IC) channels
– Four output compare (OC) channels
– One additional channel, selectable as fourth IC or fifth OC
• 8-bit pulse accumulator
• Real-time interrupt circuit
General Description
M68HC11E Family Data Sheet, Rev. 5.1
14 Freescale Semiconductor
• Computer operating properly (COP) watchdog system
• 38 general-purpose input/output (I/O) pins:
– 16 bidirectional I/O pins
– 11 input-only pins
– 11 output-only pins
• Several packaging options:
– 52-pin plastic-leaded chip carrier (PLCC)
– 52-pin windowed ceramic leaded chip carrier (CLCC)
– 52-pin plastic thin quad flat pack, 10 mm x 10 mm (TQFP)
– 64-pin quad flat pack (QFP)
– 48-pin plastic dual in-line package (DIP), MC68HC811E2 only
– 56-pin plastic shrink dual in-line package, .070-inch lead spacing (SDIP)
1.3 Structure
See Figure 1-1 for a functional diagram of the E-series MCUs. Differences among devices are noted in
the table accompanying Figure 1-1.
1.4 Pin Descriptions
M68HC11 E-series MCUs are available packaged in:
• 52-pin plastic-leaded chip carrier (PLCC)
• 52-pin windowed ceramic leaded chip carrier (CLCC)
• 52-pin plastic thin quad flat pack, 10 mm x 10 mm (TQFP)
• 64-pin quad flat pack (QFP)
• 48-pin plastic dual in-line package (DIP), MC68HC811E2 only
• 56-pin plastic shrink dual in-line package, .070-inch lead spacing (SDIP)
Most pins on these MCUs serve two or more functions, as described in the following paragraphs. Refer
to Figure 1-2, Figure 1-3, Figure 1-4, Figure 1-5, and Figure 1-6 which show the M68HC11 E-series pin
assignments for the PLCC/CLCC, QFP, TQFP, SDIP, and DIP packages.
Pin Descriptions
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 15
Figure 1-1. M68HC11 E-Series Block Diagram
PC7/ADDR7/DATA7
PC6/ADDR6/DATA6
PC5/ADDR5/DATA5
PC4/ADDR4/DATA4
PC3/ADDR3/DATA3
PC2/ADDR2/DATA2
PC1/ADDR1/DATA1
PC0/ADDR0/DATA0
MODE CONTROL
OSC
CLOCK LOGIC
INTERRUPT
LOGIC
EEPROM
(SEE TABLE)
RAM
(SEE TABLE)
SERIAL
PERIPHERAL
INTERFACE
SPI
SERIAL
COMMUNICATION
INTERFACE
SCI
M68HC11 CPU
A/D CONVERTER
CONTROL
PORT D PORT E
PE7/AN7
TxD
RxD
SS
SCK
MOSI
MISO
PD5/SS
PD0/RxD
STRA/AS
STRB/R/W
ADDRESS/DATA
BUS EXPANSION
ADDRESS
AS
STROBE AND HANDSHAKE
PARALLEL I/O
STRB
STRA
CONTROL
PORT C
PORT B
PB7/ADDR15
PORT A
PA7/PAI
TIMER
SYSTEM
COPPULSE ACCUMULATOR
OC2
OC3
OC4
OC5/IC4/OC1
IC1
IC2
IC3
PAI
PERIODIC INTERRUPT
MODA/
LIR
MODB/
VSTBY XTAL EXTAL E IRQ XIRQ/VPPE* RESET
PD4/SCK
PD3/MOSI
PD2/MISO
PD1/TxD
R/W
PA6/OC2/OC1
PA5/OC3/OC1
PA4/OC4/OC1
PA3/OC5/IC4/OC1
PA2/IC1
PA1/IC2
PA0/IC3
PB6/ADDR14
PB5/ADDR13
PB4/ADDR12
PB3/ADDR11
PB2/ADDR10
PB1/ADDR9
PB0/ADDR8
PE6/AN6
PE5/AN5
PE4/AN4
PE3/AN3
PE2/AN2
PE1/AN1
PE0/AN0
VDD
VSS
VRH
VRL
* VPPE applies only to devices with EPROM/OTPROM.
ROM OR EPROM
(SEE TABLE)
MC68HC11E0
DEVICE
512
512
512
512
768
768
RAM
—
—
12 K
—
20 K
—
ROM
—
—
—
12 K
—
20 K
EPROM
—
512
512
512
512
512
EEPROM
MC68HC11E1
MC68HC11E9
MC68HC711E9
MC68HC11E20
MC68HC711E20
256 — — 2048MC68HC811E2
General Description
M68HC11E Family Data Sheet, Rev. 5.1
16 Freescale Semiconductor
Figure 1-2. Pin Assignments for 52-Pin PLCC and CLCC
PE4/AN4
PE0/AN0
PB0/ADDR8
PB1/ADDR9
PB2/ADDR10
PB3/ADDR11
PB4/ADDR12
PB5/ADDR13
PB6/ADDR14
PB7/ADDR15
PA0/IC3
EXTAL
STRB/R/W
E
STRA/AS
MODA/LIR
MODB/VSTBY
VSS
VRH
VRL
PE7/AN7
PE3/AN3
XTAL
PC0/ADDR0/DATA0
PC1/ADDR1/DATA1
PC2/ADDR2/DATA2
PC3/ADDR3/DATA3
PC4/ADDR4/DATA4
PC5/ADDR5/DATA5
PC6/ADDR6/DATA6
PC7/ADDR7/DATA7
RESET
* XIRQ/VPPE
PD1/TxD
PD2/MISO
PD3/MOSI
PD4/SCK
PD5/SS
VDD
PA7/PAI/OC1
PA6/OC2/OC1
PA5/OC3/OC1
PA4/OC4/OC1
PA3/OC5/IC4/OC1
M68HC11 E SERIES
8
9
10
11
12
13
14
15
16
17
44
43
42
41
40
39
38
37
36
35
34
21
22
23
24
25
26
27
28
29
30
31
7
6
5
4
3
1
2
52
51
50
49
IRQ
18
PD0/RxD
19
PA2/IC1 32
PA1/IC2 33
PE6/AN6
48
PE2/AN2
47
PE1/AN1
45
PE5/AN546
20
* VPPE applies only to devices with EPROM/OTPROM.
Pin Descriptions
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 17
Figure 1-3. Pin Assignments for 64-Pin QFP
PA0/IC3
NC
NC
NC
PB7/ADDR15
PB6/ADDR14
PB5/ADDR13
PB4/ADDR12
PB3/ADDR11
PB2/ADDR10
PB1/ADDR9
PB0/ADDR8
PE0/AN0
PE4/AN4
PE1/AN1
PE5/AN5
PE2/AN2
PE6/AN6
PE3/AN3
PE7/AN7
VRL
VRH
VSS
VSS
MODB/VSTBY
MODA/LIR
NC
STRA/AS
E
STRB/R/W
NC
NC
PD0/RxD
IRQ
XIRQ/VPPE
(1)
NC
RESET
PC7/ADDR7/DATA7
PC6/ADDR6/DATA6
PC5/ADDR5/DATA5
PC3/ADDR3/DATA3
PC4/ADDR4/DATA4
PC2/ADDR2/DATA2
PC1/ADDR1/DATA1
NC
PC0/ADDR0/DATA0
XTAL
PA1/IC2
PA2/IC1
PA3/OC5/IC4/OC1
NC
NC
PA4/OC4/OC1
PA5/OC3/OC1
PA6/OC2/OC1
PA7/PAI/OC1
PD5/SS
VDD
PD4/SCK
PD3/MOSI
PD2/MISO
PD1/TxD
VSS
M68HC11 E SERIES
64
1
2
3
4
5
6
7
8
9
17
18
19
20
21
22
23
24
25
27
63
62
61
60
59
58
57
56
54
10
11
48
47
46
45
44
43
42
41
40
38
39
55
26
12
13
14
15
16
37
36
35
34
33
28
29
30
31
32
53
52
51
50
49
EXTAL
1. VPPE applies only to devices with EPROM/OTPROM.
General Description
M68HC11E Family Data Sheet, Rev. 5.1
18 Freescale Semiconductor
Figure 1-4. Pin Assignments for 52-Pin TQFP
PA0/IC3
PB7/ADDR15
PB6/ADDR14
PB5/ADDR13
PB4/ADDR12
PB3/ADDR11
PB2/ADDR10
PB1/ADDR9
PB0/ADDR8
PE0/AN0
PE4/AN4
PE1/AN1
PE5/AN5
PA1/IC2
PA2/IC1
PA3/OC5/IC4/OC1
PA4/OC4/OC1
PA5/OC3/OC1
PA6/OC2/OC1
PA7/PAI/OC1
PD5/SS
VDD
PD4/SCK
PD3/MOSI
PD2/MISO
M68HC11 E SERIES
52
1
2
3
4
5
6
7
8
9
51
50
49
48
47
46
45
44
42
10
11
43
12
13
41
40
PE2/AN2
PE6/AN6
PE3/AN3
PE7/AN7
VRL
VRH
VSS
MODB/VSTBY
MODA/LIR
STRA/AS
E
STRB/R/W
EXTAL
14
15
16
17
18
19
20
21
22
24
23
25
26
PD0/RxD
IRQ
XIRQ/VPPE
(1)
RESET
PC7/ADDR7/DATA7
PC6/ADDR6/DATA6
PC5/ADDR5/DATA5
PC3/ADDR3/DATA3
PC4/ADDR4/DATA4
PC2/ADDR2/DATA2
PC1/ADDR1/DATA1
PC0/ADDR0/DATA0
XTAL
39
38
37
36
35
34
33
32
31
29
30
28
27
PD1/TxD
1. VPPE applies only to devices with EPROM/OTPROM.
Pin Descriptions
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 19
Figure 1-5. Pin Assignments for 56-Pin SDIP
* VPPE applies only to devices with EPROM/OTPROM.
PC0/ADDR0/DATA0
PC1/ADDR1/DATA1
PC2/ADDR2/DATA2
PC3/ADDR3/DATA3
PC4/ADDR4/DATA4
PC5/ADDR5/DATA5
PC6/ADDR6/DATA6
PC7/ADDR7/DATA7
RESET
* XIRQ/VPPE
M68HC11 E SERIES
9
10
11
12
13
14
15
16
17
18
IRQ 19
PD0/RxD 20
21
PD1/TxD 22
PD2/MISO 23
PD3/MOSI 24
PD4/SCK 25
PD5/SS 26
VDD 27
VSS 28
XTAL 8
EXTAL 7
STRB/R/W 6
5
STRA/AS 4
MODA/LIR 3
MODB/VSTBY 2
VSS 1
PE0/AN0
PB0/ADDR8
PB1/ADDR9
PB2/ADDR10
PB3/ADDR11
PB4/ADDR12
PB5/ADDR13
PB6/ADDR14
PB7/ADDR15
PA0/IC3
PA1/IC2
46
45
44
43
42
41
40
39
38
37
36
PE4/AN4
47
PE1/AN1
48
PA2/IC1
35
PA3/OC5/IC4/OC1
34
PA4/OC4/OC1
33
PA5/OC3/OC1
32
PA6/OC2/OC1
31
PA7/PAI/OC1
30
EVDD
29
PE5/AN5
49
PE2/AN2
50
PE6/AN6
51
PE3/AN3
52
PE7/AN7
53
VRL
54
VRH
55
EVSS
56
EVSS
E
General Description
M68HC11E Family Data Sheet, Rev. 5.1
20 Freescale Semiconductor
Figure 1-6. Pin Assignments for 48-Pin DIP (MC68HC811E2)
PB7/ADDR15
PB6/ADDR14
PB5/ADDR13
PB4/ADDR12
PB3/ADDR11
PB2/ADDR10
PB1/ADDR9
PB0/ADDR8
PE0/AN0
PE1/AN1
MC68HC811E2
9
10
11
12
13
14
15
16
17
18
PE2/AN2 19
PE3/AN3 20
21
VRH 22
VSS 23
MODB/VSTBY 24
PA0/IC3 8
PA1/IC2 7
PA2/IC1 6
PA3/OC5/IC4/OC1 5
PA4/OC4/OC1 4
PA5/OC3/OC1 3
PA6/OC2/OC1 2
PA7/PAI/OC1 1
PC7/ADDR7/DATA7
PC6/ADDR6/DATA6
PC5/ADDR5/DATA5
PC4/ADDR4/DATA4
PC3/ADDR3/DATA3
PC2/ADDR2/DATA2
PC1/ADDR1/DATA1
PC0/ADDR0/DATA0
XTAL
EXTAL
STRB/R/W
38
37
36
35
34
33
32
31
30
29
28
RESET
39
XIRQ
40
E27
STRA/AS26
MODA/LIR
25
IRQ
41
PD0/RxD42
PD1/TxD
43
PD2/MISO44
PD3/MOSI
45
PD4/SCK46
PD5/SS
47
VDD
48
VRL
Pin Descriptions
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 21
1.4.1 VDD and VSS
Power is supplied to the MCU through VDD and VSS. VDD is the power supply, VSS is ground. The MCU
operates from a single 5-volt (nominal) power supply. Low-voltage devices in the E series operate at
3.0–5.5 volts.
Very fast signal transitions occur on the MCU pins. The short rise and fall times place high, short duration
current demands on the power supply. To prevent noise problems, provide good power supply bypassing
at the MCU. Also, use bypass capacitors that have good
high-frequency characteristics and situate them as close to the MCU as possible. Bypass requirements
vary, depending on how heavily the MCU pins are loaded.
Figure 1-7. External Reset Circuit
Figure 1-8. External Reset Circuit with Delay
4.7 kΩ
TO RESET
VDD
MC34(0/1)64
RESET
GND
IN
OF M68HC11
2
1
3
VDD
TO RESET
VDD
MC34064
RESET
GND
IN
OF M68HC11
RESET
GND
IN
MANUAL
RESET SWITCH
4.7 kΩ
1.0 µF
MC34164
4.7 kΩ
VDD
VDD
OPTIONAL POWER-ON DELAY AND MANUAL RESET SWITCH
4.7 kΩ
General Description
M68HC11E Family Data Sheet, Rev. 5.1
22 Freescale Semiconductor
1.4.2 RESET
A bidirectional control signal, RESET, acts as an input to initialize the MCU to a known startup state. It
also acts as an open-drain output to indicate that an internal failure has been detected in either the clock
monitor or computer operating properly (COP) watchdog circuit. The CPU distinguishes between internal
and external reset conditions by sensing whether the reset pin rises to a logic 1 in less than two E-clock
cycles after a reset has occurred. See Figure 1-7 and Figure 1-8.
CAUTION
Do not connect an external resistor capacitor (RC) power-up delay circuit
to the reset pin of M68HC11 devices because the circuit charge time
constant can cause the device to misinterpret the type of reset that
occurred.
Because the CPU is not able to fetch and execute instructions properly when VDD falls below the minimum
operating voltage level, reset must be controlled. A low-voltage inhibit (LVI) circuit is required primarily for
protection of EEPROM contents. However, since the configuration register (CONFIG) value is read from
the EEPROM, protection is required even if the EEPROM array is not being used.
Presently, there are several economical ways to solve this problem. For example, two good external
components for LVI reset are:
1. The Seiko S0854HN (or other S805 series devices):
a. Extremely low power (2 µA)
a. TO-92 package
a. Limited temperature range, –20°C to +70°C
a. Available in various trip-point voltage ranges
2. The Freescale MC34064:
a. TO-92 or SO-8 package
a. Draws about 300 µA
a. Temperature range –40°C to 85°C
a. Well controlled trip point
a. Inexpensive
Refer to Chapter 5 Resets and Interrupts for further information.
1.4.3 Crystal Driver and External Clock Input (XTAL and EXTAL)
These two pins provide the interface for either a crystal or a CMOS- compatible clock to control the
internal clock generator circuitry. The frequency applied to these pins is four times higher than the desired
E-clock rate.
The XTAL pin must be left unterminated when an external CMOS- compatible clock input is connected to
the EXTAL pin. The XTAL output is normally intended to drive only a crystal. Refer to Figure 1-9 and
Figure 1-10.
CAUTION
In all cases, use caution around the oscillator pins. Load capacitances
shown in the oscillator circuit are specified by the crystal manufacturer and
should include all stray layout capacitances.
Pin Descriptions
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 23
Figure 1-9. Common Parallel Resonant Crystal Connections
Figure 1-10. External Oscillator Connections
1.4.4 E-Clock Output (E)
E is the output connection for the internally generated E clock. The signal from E is used as a timing
reference. The frequency of the E-clock output is one fourth that of the input frequency at the XTAL and
EXTAL pins. When E-clock output is low, an internal process is taking place. When it is high, data is being
accessed.
All clocks, including the E clock, are halted when the MCU is in stop mode. To reduce RFI emissions, the
E-clock output of most E-series devices can be disabled while operating in single-chip modes.
The E-clock signal is always enabled on the MC68HC811E2.
1.4.5 Interrupt Request (IRQ)
The IRQ input provides a means of applying asynchronous interrupt requests to the MCU. Either negative
edge-sensitive triggering or level-sensitive triggering is program selectable (OPTION register). IRQ is
always configured to level-sensitive triggering at reset. When using IRQ in a level-sensitive wired-OR
configuration, connect an external pullup resistor, typically 4.7 kΩ, to VDD.
1.4.6 Non-Maskable Interrupt (XIRQ/VPPE)
The XIRQ input provides a means of requesting a non-maskable interrupt after reset initialization. During
reset, the X bit in the condition code register (CCR) is set and any interrupt is masked until MCU software
enables it. Because the XIRQ input is level-sensitive, it can be connected to a multiple-source wired-OR
network with an external pullup resistor to VDD. XIRQ is often used as a power loss detect interrupt.
Whenever XIRQ or IRQ is used with multiple interrupt sources each source must drive the interrupt input
with an open-drain type of driver to avoid contention between outputs.
10 MΩ
MCU
CL
CL
EXTAL
XTAL
4 x E
CRYSTAL
NC
MCU
EXTAL
XTAL
4 x E
CMOS-COMPATIBLE
EXTERNAL OSCILLATOR
General Description
M68HC11E Family Data Sheet, Rev. 5.1
24 Freescale Semiconductor
NOTE
IRQ must be configured for level-sensitive operation if there is more than
one source of IRQ interrupt.
There should be a single pullup resistor near the MCU interrupt input pin (typically 4.7 kΩ). There must
also be an interlock mechanism at each interrupt source so that the source holds the interrupt line low
until the MCU recognizes and acknowledges the interrupt request. If one or more interrupt sources are
still pending after the MCU services a request, the interrupt line will still be held low and the MCU will be
interrupted again as soon as the interrupt mask bit in the MCU is cleared (normally upon return from an
interrupt). Refer to Chapter 5 Resets and Interrupts.
VPPE is the input for the 12-volt nominal programming voltage required for EPROM/OTPROM
programming. On devices without EPROM/OTPROM, this pin is only an XIRQ input.
CAUTION
During EPROM programming of the MC68HC711E9 device, the VPPE pin
circuitry may latch-up and be damaged if the input current is not limited to
10 mA. For more information please refer to MC68HC711E9 8-Bit
Microcontroller Unit Mask Set Errata 3 (Freescale document order number
68HC711E9MSE3.
1.4.7 MODA and MODB (MODA/LIR and MODB/VSTBY)
During reset, MODA and MODB select one of the four operating modes:
• Single-chip mode
• Expanded mode
• Test mode
• Bootstrap mode
Refer to Chapter 2 Operating Modes and On-Chip Memory.
After the operating mode has been selected, the load instruction register (LIR) pin provides an open-drain
output to indicate that execution of an instruction has begun. A series of E-clock cycles occurs during
execution of each instruction. The LIR signal goes low during the first E-clock cycle of each instruction
(opcode fetch). This output is provided for assistance in program debugging.
The VSTBY pin is used to input random-access memory (RAM) standby power. When the voltage on this
pin is more than one MOS threshold (about 0.7 volts) above the VDD voltage, the internal RAM and part
of the reset logic are powered from this signal rather than the VDD input. This allows RAM contents to be
retained without VDD power applied to the MCU. Reset must be driven low before VDD is removed and
must remain low until VDD has been restored to a valid level.
1.4.8 VRL and VRH
These two inputs provide the reference voltages for the analog-to-digital (A/D) converter circuitry:
•V
RL is the low reference, typically 0 Vdc.
•V
RH is the high reference.
For proper A/D converter operation:
•V
RH should be at least 3 Vdc greater than VRL.
•V
RL and VRH should be between VSS and VDD.
Pin Descriptions
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 25
1.4.9 STRA/AS
The strobe A (STRA) and address strobe (AS) pin performs either of two separate functions, depending
on the operating mode:
• In single-chip mode, STRA performs an input handshake (strobe input) function.
• In the expanded multiplexed mode, AS provides an address strobe function.
AS can be used to demultiplex the address and data signals at port C. Refer to Chapter 2 Operating
Modes and On-Chip Memory.
1.4.10 STRB/R/W
The strobe B (STRB) and read/write (R/W) pin act as either an output strobe or as a data bus direction
indicator, depending on the operating mode.
In single-chip operating mode, STRB acts as a programmable strobe for handshake with other parallel
devices. Refer to Chapter 6 Parallel Input/Output (I/O) Ports for further information.
In expanded multiplexed operating mode, R/W is used to indicate the direction of transfers on the external
data bus. A low on the R/W pin indicates data is being written to the external data bus. A high on this pin
indicates that a read cycle is in progress. R/W stays low during consecutive data bus write cycles, such
as a double-byte store. It is possible for data to be driven out of port C, if internal read visibility (IRV) is
enabled and an internal address is read, even though R/W is in a high-impedance state. Refer to
Chapter 2 Operating Modes and On-Chip Memory for more information about IRVNE (internal read
visibility not E).
1.4.11 Port Signals
Port pins have different functions in different operating modes. Pin functions for port A, port D, and port
E are independent of operating modes. Port B and port C, however, are affected by operating mode. Port
B provides eight general-purpose output signals in single-chip operating modes. When the microcontroller
is in expanded multiplexed operating mode, port B pins are the eight high-order address lines.
Port C provides eight general-purpose input/output signals when the MCU is in the single-chip operating
mode. When the microcontroller is in the expanded multiplexed operating mode, port C pins are a
multiplexed address/data bus.
Refer to Table 1-1 for a functional description of the 40 port signals within different operating modes.
Terminate unused inputs and input/output (I/O) pins configured as inputs high or low.
1.4.12 Port A
In all operating modes, port A can be configured for three timer input capture (IC) functions and four timer
output compare (OC) functions. An additional pin can be configured as either the fourth IC or the fifth OC.
Any port A pin that is not currently being used for a timer function can be used as either a general-purpose
input or output line. Only port A pins PA7 and PA3 have an associated data direction control bit that allows
the pin to be selectively configured as input or output. Bits DDRA7 and DDRA3 located in PACTL register
control data direction for PA7 and PA3, respectively. All other port A pins are fixed as either input or
output.
PA7 can function as general-purpose I/O or as timer output compare for OC1. PA7 is also the input to the
pulse accumulator, even while functioning as a general-purpose I/O or an OC1 output.
General Description
M68HC11E Family Data Sheet, Rev. 5.1
26 Freescale Semiconductor
Table 1-1. Port Signal Functions
Port/Bit Single-Chip and
Bootstrap Modes
Expanded and
Test Modes
PA0 PA0 /IC 3
PA1 PA1 /IC 2
PA2 PA2 /IC 1
PA3 PA3/OC5/IC4/OC1
PA4 PA4/OC4/OC1
PA5 PA5/OC3/OC1
PA6 PA6/OC2/OC1
PA7 PA7/PAI/OC1
PB0 PB0 ADDR8
PB1 PB1 ADDR9
PB2 PB2 ADDR10
PB3 PB3 ADDR11
PB4 PB4 ADDR12
PB5 PB5 ADDR13
PB6 PB6 ADDR14
PB7 PB7 ADDR15
PC0 PC0 ADDR0/DATA0
PC1 PC1 ADDR1/DATA1
PC2 PC2 ADDR2/DATA2
PC3 PC3 ADDR3/DATA3
PC4 PC4 ADDR4/DATA4
PC5 PC5 ADDR5/DATA5
PC6 PC6 ADDR6/DATA6
PC7 PC7 ADDR7/DATA7
PD0 PD0/RxD
PD1 PD1/TxD
PD2 PD2/MISO
PD3 PD3/MOSI
PD4 PD4/SCK
PD5 PD5/SS
— STRA AS
—STRB R/W
PE0 PE0/AN0
PE1 PE1/AN1
PE2 PE3/AN2
PE3 PE3/AN3
PE4 PE4/AN4
PE5 PE5/AN5
PE6 PE6/AN6
PE7 PE7/AN7
Pin Descriptions
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 27
PA6–PA4 serve as either general-purpose outputs, timer input captures, or timer output compare 2–4. In
addition, PA6–PA4 can be controlled by OC1.
PA3 can be a general-purpose I/O pin or a timer IC/OC pin. Timer functions associated with this pin
include OC1 and IC4/OC5. IC4/OC5 is software selectable as either a fourth input capture or a fifth output
compare. PA3 can also be configured to allow OC1 edges to trigger IC4 captures.
PA2–PA0 serve as general-purpose inputs or as IC1–IC3.
PORTA can be read at any time. Reads of pins configured as inputs return the logic level present on the
pin. Pins configured as outputs return the logic level present at the pin driver input. If written, PORTA
stores the data in an internal latch, bits 7 and 3. It drives the pins only if they are configured as outputs.
Writes to PORTA do not change the pin state when pins are configured for timer input captures or output
compares. Refer to Chapter 6 Parallel Input/Output (I/O) Ports.
1.4.13 Port B
During single-chip operating modes, all port B pins are general-purpose output pins. During MCU reads
of this port, the level sensed at the input side of the port B output drivers is read. Port B can also be used
in simple strobed output mode. In this mode, an output pulse appears at the STRB signal each time data
is written to port B.
In expanded multiplexed operating modes, all of the port B pins act as high order address output signals.
During each MCU cycle, bits 15–8 of the address bus are output on the PB7–PB0 pins. The PORTB
register is treated as an external address in expanded modes.
1.4.14 Port C
While in single-chip operating modes, all port C pins are general-purpose I/O pins. Port C inputs can be
latched into an alternate PORTCL register by providing an input transition to the STRA signal. Port C can
also be used in full handshake modes of parallel I/O where the STRA input and STRB output act as
handshake control lines.
When in expanded multiplexed modes, all port C pins are configured as multiplexed address/data signals.
During the address portion of each MCU cycle, bits 7–0 of the address are output on the PC7–PC0 pins.
During the data portion of each MCU cycle (E high), PC7–PC0 are bidirectional data signals,
DATA7–DATA0. The direction of data at the port C pins is indicated by the R/W signal.
The CWOM control bit in the PIOC register disables the port C P-channel output driver. CWOM
simultaneously affects all eight bits of port C. Because the N-channel driver is not affected by CWOM,
setting CWOM causes port C to become an open-drain type output port suitable for wired-OR operation.
In wired-OR mode:
• When a port C bit is at logic level 0, it is driven low by the N-channel driver.
• When a port C bit is at logic level 1, the associated pin has high-impedance, as neither the
N-channel nor the P-channel devices are active.
It is customary to have an external pullup resistor on lines that are driven by open-drain devices. Port C
can only be configured for wired-OR operation when the MCU is in single-chip mode. Refer to Chapter 6
Parallel Input/Output (I/O) Ports for additional information about port C functions.
General Description
M68HC11E Family Data Sheet, Rev. 5.1
28 Freescale Semiconductor
1.4.15 Port D
Pins PD5–PD0 can be used for general-purpose I/O signals. These pins alternately serve as the serial
communication interface (SCI) and serial peripheral interface (SPI) signals when those subsystems are
enabled.
• PD0 is the receive data input (RxD) signal for the SCI.
• PD1 is the transmit data output (TxD) signal for the SCI.
• PD5–PD2 are dedicated to the SPI:
– PD2 is the master in/slave out (MISO) signal.
– PD3 is the master out/slave in (MOSI) signal.
– PD4 is the serial clock (SCK) signal.
– PD5 is the slave select (SS) input.
1.4.16 Port E
Use port E for general-purpose or analog-to-digital (A/D) inputs.
CAUTION
If high accuracy is required for A/D conversions, avoid reading port E during
sampling, as small disturbances can reduce the accuracy of that result.
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 29
Chapter 2
Operating Modes and On-Chip Memory
2.1 Introduction
This section contains information about the operating modes and the on-chip memory for M68HC11
E-series MCUs. Except for a few minor differences, operation is identical for all devices in the E series.
Differences are noted where necessary.
2.2 Operating Modes
The values of the mode select inputs MODB and MODA during reset determine the operating mode.
Single-chip and expanded multiplexed are the normal modes.
• In single-chip mode only on-chip memory is available.
• Expanded mode, however, allows access to external memory.
Each of the two normal modes is paired with a special mode:
• Bootstrap, a variation of the single-chip mode, is a special mode that executes a bootloader
program in an internal bootstrap ROM.
• Test is a special mode that allows privileged access to internal resources.
2.2.1 Single-Chip Mode
In single-chip mode, ports B and C and strobe pins A (STRA) and B (STRB) are available for
general-purpose parallel input/output (I/O). In this mode, all software needed to control the MCU is
contained in internal resources. If present, read-only memory (ROM) and/or erasable, programmable
read-only memory (EPROM) will always be enabled out of reset, ensuring that the reset and interrupt
vectors will be available at locations $FFC0–$FFFF.
NOTE
For the MC68HC811E2, the vector locations are the same; however, they
are contained in the 2048-byte EEPROM array.
2.2.2 Expanded Mode
In expanded operating mode, the MCU can access the full 64-Kbyte address space. The space includes:
• The same on-chip memory addresses used for single-chip mode
• Addresses for external peripherals and memory devices
The expansion bus is made up of ports B and C, and control signals AS (address strobe) and R/W
(read/write). R/W and AS allow the low-order address and the 8-bit data bus to be multiplexed on the
same pins. During the first half of each bus cycle address information is present. During the second half
of each bus cycle the pins become the bidirectional data bus. AS is an active-high latch enable signal for
an external address latch. Address information is allowed through the transparent latch while AS is high
and is latched when AS drives low.
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
30 Freescale Semiconductor
The address, R/W, and AS signals are active and valid for all bus cycles, including accesses to internal
memory locations. The E clock is used to enable external devices to drive data onto the internal data bus
during the second half of a read bus cycle (E clock high). R/W controls the direction of data transfers. R/W
drives low when data is being written to the internal data bus. R/W will remain low during consecutive data
bus write cycles, such as when a double-byte store occurs.
Refer to Figure 2-1.
NOTE
The write enable signal for an external memory is the NAND of the E clock
and the inverted R/W signal.
Figure 2-1. Address/Data Demultiplexing
2.2.3 Test Mode
Test mode, a variation of the expanded mode, is primarily used during Freescale’s internal production
testing; however, it is accessible for programming the configuration (CONFIG) register, programming
calibration data into electrically erasable, programmable read-only memory (EEPROM), and supporting
emulation and debugging during development.
2.2.4 Bootstrap Mode
When the MCU is reset in special bootstrap mode, a small on-chip read-only memory (ROM) is enabled
at address $BF00–$BFFF. The ROM contains a bootloader program and a special set of interrupt and
reset vectors. The MCU fetches the reset vector, then executes the bootloader.
Bootstrap mode is a special variation of the single-chip mode. Bootstrap mode allows special-purpose
programs to be entered into internal random-access memory (RAM). When bootstrap mode is selected
at reset, a small bootstrap ROM becomes present in the memory map. Reset and interrupt vectors are
HC373
MCU
ADDR14
ADDR13
ADDR12
ADDR11
ADDR10
ADDR9
ADDR8
ADDR15
ADDR6
ADDR5
ADDR4
ADDR3
ADDR2
ADDR1
ADDR0
ADDR7
DATA6
DATA5
DATA4
DATA3
DATA2
DATA1
DATA0
DATA7
D2
D3
D4
D5
D6
D7
D8
D1 Q2
Q3
Q4
Q5
Q6
Q7
Q8
Q1
OE
LE
PC6
PC5
PC4
PC3
PC2
PC1
PC0
PC7
AS
PB6
PB5
PB4
PB3
PB2
PB1
PB0
PB7
R/W
EWE
OE
Memory Map
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 31
located in this ROM at $BFC0–$BFFF. The bootstrap ROM contains a small program which initializes the
serial communications interface (SCI) and allows the user to download a program into on-chip RAM. The
size of the downloaded program can be as large as the size of the on-chip RAM. After a 4-character delay,
or after receiving the character for the highest address in RAM, control passes to the loaded program at
$0000. Refer to Figure 2-2, Figure 2-3, Figure 2-4, Figure 2-5, and Figure 2-6.
Use of an external pullup resistor is required when using the SCI transmitter pin because port D pins are
configured for wired-OR operation by the bootloader. In bootstrap mode, the interrupt vectors are directed
to RAM. This allows the use of interrupts through a jump table. Refer to the application note AN1060
entitled M68HC11 Bootstrap Mode, that is included in this data book.
2.3 Memory Map
The operating mode determines memory mapping and whether external addresses can be accessed.
Refer to Figure 2-2, Figure 2-3, Figure 2-4, Figure 2-5, and Figure 2-6, which illustrate the memory maps
for each of the three families comprising the M68HC11 E series of MCUs.
Memory locations for on-chip resources are the same for both expanded and single-chip modes. Control
bits in the configuration (CONFIG) register allow EPROM and EEPROM (if present) to be disabled from
the memory map. The RAM is mapped to $0000 after reset. It can be placed at any 4-Kbyte boundary
($x000) by writing an appropriate value to the RAM and I/O map register (INIT). The 64-byte register block
is mapped to $1000 after reset and also can be placed at any 4-Kbyte boundary ($x000) by writing an
appropriate value to the INIT register. If RAM and registers are mapped to the same boundary, the first
64 bytes of RAM will be inaccessible.
Refer to Figure 2-7, which details the MCU register and control bit assignments. Reset states shown are
for single-chip mode only.
Figure 2-2. Memory Map for MC68HC11E0
FFC0
FFFF
NORMAL
MODES
INTERRUPT
VECTORS
64-BYTE REGISTER BLOCK
512 BYTES RAM
BOOTSTRAP SPECIAL
TEST
EXT
0000
1000
103F
BF00
EXPANDED
BFFF
BFC0
BFFF
SPECIAL MODES
INTERRUPT
VECTORS
BOOT
ROM
EXT EXT
01FF
EXT
$0000
$1000
$B600
$D000
$FFFF
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
32 Freescale Semiconductor
Figure 2-3. Memory Map for MC68HC11E1
Figure 2-4. Memory Map for MC68HC(7)11E9
FFC0
FFFF
NORMAL
MODES
INTERRUPT
VECTORS
64-BYTE REGISTER BLOCK
512 BYTES RAM
BOOTSTRAP SPECIAL
TEST
EXT
$0000
$1000
$B600
$D000
$FFFF
0000
1000
103F
BF00
EXPANDED
BFFF
BFC0
BFFF
SPECIAL MODES
INTERRUPT
VECTORS
B600
B7FF
512 BYTES EEPROM
BOOT
ROM
EXT EXT
EXT
01FF
EXT
EXT
FFC0
FFFF
NORMAL
MODES
INTERRUPT
VECTORS
64-BYTE REGISTER BLOCK
512 BYTES RAM
SINGLE
CHIP
BOOTSTRAP SPECIAL
TEST
EXT
$0000
$1000
$B600
$D000
$FFFF
0000
1000
103F
BF00
EXPANDED
D000
FFFF
BFFF
BFC0
BFFF
SPECIAL MODES
INTERRUPT
VECTORS
B600
B7FF
512 BYTES EEPROM
12 KBYTES ROM/EPROM
BOOT
ROM
EXT EXT
EXT
01FF
EXT
EXT
Memory Map
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 33
Figure 2-5. Memory Map for MC68HC(7)11E20
Figure 2-6. Memory Map for MC68HC811E2
9000
AFFF
8 KBYTES ROM/EPROM *
* 20 Kbytes ROM/EPROM are contained in two segments of 8 Kbytes and 12 Kbytes each.
FFC0
FFFF
NORMAL
MODES
INTERRUPT
VECTORS
64-BYTE REGISTER BLOCK
768 BYTES RAM
SINGLE
CHIP
BOOTSTRAP SPECIAL
TEST
EXT
$0000
$1000
$B600
$D000
$FFFF
0000
1000
103F
BF00
EXPANDED
D000
FFFF
BFFF
BFC0
BFFF
SPECIAL MODES
INTERRUPT
VECTORS
B600
B7FF
512 BYTES EEPROM
12 KBYTES ROM/EPROM *
BOOT
ROM
EXT
EXT
02FF
EXT
EXT
$9000
EXT
EXT
EXT
FFC0
FFFF
NORMAL
MODES
INTERRUPT
VECTORS
64-BYTE REGISTER BLOCK
256 BYTES RAM
SINGLE
CHIP
BOOTSTRAP SPECIAL
TEST
EXT
$0000
$1000
$F800
$FFFF
0000
1000
103F
BF00
EXPANDED
F800
FFFF
BFFF
BFC0
BFFF
SPECIAL MODES
INTERRUPT
VECTORS
2048 BYTES EEPROM
BOOT
ROM
EXT EXT
00FF
EXT
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
34 Freescale Semiconductor
Addr. Register Name Bit 7 6 5 4 3 2 1 Bit 0
$1000
Port A Data Register
(PORTA)
See page 98.
Read:
PA7 PA6 PA5 PA4 PA3 PA2 PA1 PA0
Write:
Reset: I 0 0 0 I I I I
$1001 Reserved R R R R R R R R
$1002
Parallel I/O Control Register
(PIOC)
See page 102.
Read:
STAF STAI CWOM HNDS OIN PLS EGA INVB
Write:
Reset: 0 0 0 0 0 U 1 1
$1003
Port C Data Register
(PORTC)
See page 99.
Read:
PC7 PC6 PC5 PC4 PC3 PC2 PC1 PC0
Write:
Reset: Indeterminate after reset
$1004
Port B Data Register
(PORTB)
See page 99.
Read:
PB7 PB6 PB5 PB4 PB3 PB2 PB1 PB0
Write:
Reset: 0 0 0 0 0 0 0 0
$1005
Port C Latched Register
(PORTCL)
See page 99.
Read:
PCL7 PCL6 PCL5 PCL4 PCL3 PCL2 PCL1 PCL0
Write:
Reset: Indeterminate after reset
$1006 Reserved R R R R R R R R
$1007
Port C Data Direction Register
(DDRC)
See page 100.
Read:
DDRC7 DDRC6 DDRC5 DDRC4 DDRC3 DDRC2 DDRC1 DDRC0
Write:
Reset: 0 0 0 0 0 0 0 0
$1008
Port D Data Register
(PORTD)
See page 100.
Read:
0 0 PD5 PD4 PD3 PD2 PD1 PD0
Write:
Reset: U U I I I I I I
$1009
Port D Data Direction Register
(DDRD)
See page 100.
Read:
DDRD5 DDRD4 DDRD3 DDRD2 DDRD1 DDRD0
Write:
Reset: 0 0 0 0 0 0 0 0
$100A
Port E Data Register
(PORTE)
See page 101.
Read:
PE7 PE6 PE5 PE4 PE3 PE2 PE1 PE0
Write:
Reset: Indeterminate after reset
$100B
Timer Compare Force Register
(CFORC)
See page 135.
Read:
FOC1 FOC2 FOC3 FOC4 FOC5
Write:
Reset: 0 0 0 0 0 0 0 0
$100C
Output Compare 1 Mask Register
(OC1M)
See page 136.
Read:
OC1M7 OC1M6 OC1M5 OC1M4 OC1M3
Write:
Reset: 0 0 0 0 0 0 0 0
= Unimplemented R = Reserved U = Unaffected
I = Indeterminate after reset
Figure 2-7. Register and Control Bit Assignments (Sheet 1 of 6)
Memory Map
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 35
$100D
Output Compare 1 Data Register
(OC1D)
See page 136.
Read:
OC1D7 OC1D6 OC1D5 OC1D4 OC1D3
Write:
Reset: 0 0 0 0 0 0 0 0
$100E
Timer Counter Register High
(TCNTH)
See page 137.
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 0 0 0 0 0 0 0 0
$100F
Timer Counter Register Low
(TCNTL)
See page 137.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 0 0 0 0 0 0 0 0
$1010
Timer Input Capture 1 Register
High (TIC1H)
See page 132.
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: Indeterminate after reset
$1011
Timer Input Capture 1 Register
Low (TIC1L)
See page 132.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
$1012
Timer Input Capture 2 Register
High (TIC2H)
See page 132.
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: Indeterminate after reset
$1013
TImer Input Capture 2 Register
Low (TIC2L)
See page 132.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
$1014
Timer Input Capture 3 Register
High (TIC3H)
See page 132.
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: Indeterminate after reset
$1015
Timer Input Capture 3 Register
Low (TIC3L)
See page 132.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
$1016
Timer Output Compare 1 Register
High (TOC1H)
See page 134.
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 11 1 1 1 1 11
$1017
Timer Output Compare 1 Register
Low (TOC1L)
See page 134.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 11 1 1 1 1 11
$1018
Timer Output Compare 2 Register
High (TOC2H)
See page 134.
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 11 1 1 1 1 11
Addr. Register Name Bit 7 6 5 4 3 2 1 Bit 0
= Unimplemented R = Reserved U = Unaffected
I = Indeterminate after reset
Figure 2-7. Register and Control Bit Assignments (Sheet 2 of 6)
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
36 Freescale Semiconductor
$1019
Timer Output Compare 2 Register
Low (TOC2L)
See page 134.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 11 1 1 1 1 11
$101A
Timer Output Compare 3 Register
High (TOC3H)
See page 135.
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 11 1 1 1 1 11
$101B
Timer Output Compare 3 Register
Low (TOC3L)
See page 135.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 11 1 1 1 1 11
$101C
Timer Output Compare 4 Register
High (TOC4H)
See page 135.
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 11 1 1 1 1 11
$101D
Timer Output Compare 4 Register
Low (TOC4L)
See page 135.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 11 1 1 1 1 11
$101E
Timer Input Capture 4/Output
Compare 5 Register High
(TI4/O5) See page 133.
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 11 1 1 1 1 11
$101F
Timer Input Capture 4/Output
Compare 5 Register Low
(TI4/O5) See page 133.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 11 1 1 1 1 11
$1020
Timer Control Register 1
(TCTL1)
See page 137.
Read:
OM2 OL2 OM3 OL3 OM4 OL4 OM5 OL5
Write:
Reset: 0 0 0 0 0 0 0 0
$1021
Timer Control Register 2
(TCTL2)
See page 131.
Read:
EDG4B EDG4A EDG1B EDG1A EDG2B EDG2A EDG3B EDG3A
Write:
Reset: 0 0 0 0 0 0 0 0
$1022
Timer Interrupt Mask 1 Register
(TMSK1)
See page 138.
Read:
OC1I OC2I OC3I OC4I I4/O5I IC1I IC2I IC3I
Write:
Reset: 0 0 0 0 0 0 0 0
$1023
Timer Interrupt Flag 1
(TFLG1)
See page 138.
Read:
OC1F OC2F OC3F OC4F I4/O5F IC1F IC2F IC3F
Write:
Reset: 0 0 0 0 0 0 0 0
$1024
Timer Interrupt Mask 2 Register
(TMSK2)
See page 139.
Read:
TOI RTII PAOVI PAII PR1 PR0
Write:
Reset: 0 0 0 0 0 0 0 0
Addr. Register Name Bit 7 6 5 4 3 2 1 Bit 0
= Unimplemented R = Reserved U = Unaffected
I = Indeterminate after reset
Figure 2-7. Register and Control Bit Assignments (Sheet 3 of 6)
Memory Map
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 37
$1025
Timer Interrupt Flag 2
(TFLG2)
See page 142.
Read:
TOF RTIF PAOVF PAIF
Write:
Reset: 0 0 0 0 0 0 0 0
$1026
Pulse Accumulator Control Regis-
ter (PACTL)
See page 142.
Read:
DDRA7 PAEN PAMOD PEDGE DDRA3 I4/O5 RTR1 RTR0
Write:
Reset: 0 0 0 0 0 0 0 0
$1027
Pulse Accumulator Count Regis-
ter (PACNT)
See page 146.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
$1028
Serial Peripheral Control Register
(SPCR)
See page 123.
Read:
SPIE SPE DWOM MSTR CPOL CPHA SPR1 SPR0
Write:
Reset: 0 0 0 0 0 1 U U
$1029
Serial Peripheral Status Register
(SPSR)
See page 124.
Read:
SPIF WCOL MODF
Write:
Reset: 0 0 0 0 0 0 0 0
$102A
Serial Peripheral Data I/O Regis-
ter (SPDR)
See page 125.
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
$102B
Baud Rate Register
(BAUD)
See page 113.
Read:
TCLR SCP2(1) SCP1 SCP0 RCKB SCR2 SCR1 SCR0
Write:
Reset: 0 0 0 0 0 U U U
$102C
Serial Communications Control
Register 1 (SCCR1)
See page 110.
Read:
R8 T8 M WAKE
Write:
Reset: I I 0 0 0 0 0 0
$102D
Serial Communications Control
Register 2 (SCCR2)
See page 111.
Read:
TIE TCIE RIE ILIE TE RE RWU SBK
Write:
Reset: 0 0 0 0 0 0 0 0
$102E
Serial Communications Status
Register (SCSR)
See page 112.
Read:
TDRE TC RDRF IDLE OR NF FE
Write:
Reset: 1 1 0 0 0 0 0 0
1. SCP2 adds ÷39 to SCI prescaler and is present only in MC68HC(7)11E20.
$102F
Serial Communications Data Reg-
ister (SCDR)
See page 110.
Read:
R7/T7 R6/T6 R5/T5 R4/T4 R3/T3 R2/T2 R1/T1 R0/T0
Write:
Reset: Indeterminate after reset
$1030
Analog-to-Digital Control Status
Register (ADCTL)
See page 62.
Read: CCF SCAN MULT CD CC CB CA
Write:
Reset: 0 0 Indeterminate after reset
Addr. Register Name Bit 7 6 5 4 3 2 1 Bit 0
= Unimplemented R = Reserved U = Unaffected
I = Indeterminate after reset
Figure 2-7. Register and Control Bit Assignments (Sheet 4 of 6)
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
38 Freescale Semiconductor
$1031
Analog-to-Digital Results
Register 1 (ADR1)
See page 64.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
$1032
Analog-to-Digital Results
Register 2 (ADR2)
See page 64.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
$1033
Analog-to-Digital Results
Register 3 (ADR3)
See page 64.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
$1034
Analog-to-Digital Results
Register 4 (ADR4)
See page 64.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
$1035
Block Protect Register
(BPROT)
See page 52.
Read:
PTCON BPRT3 BPRT2 BPRT1 BPRT0
Write:
Reset: 0 0 0 1 1 1 1 1
$1036
EPROM Programming Control
Register (EPROG)(1)
See page 53.
Read:
MBE ELAT EXCOL EXROW T1 T0 PGM
Write:
Reset: 0 0 0 0 0 0 0 0
$1037 Reserved R R R R R R R R
1. MC68HC711E20 only
$1038 Reserved R R R R R R R R
$1039
System Configuration Options
Register (OPTION)
See page 46.
Read:
ADPU CSEL IRQE(1) DLY(1) CME CR1(1) CR0(1)
Write:
Reset: 0 0 0 1 0 0 0 0
$103A
Arm/Reset COP Timer Circuitry
Register (COPRST)
See page 81.
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 0 0 0 0 0 0 0 0
$103B
EPROM and EEPROM Program-
ming Control Register (PPROG)
See page 49.
Read:
ODD EVEN ELAT(2) BYTE ROW ERASE EELAT EPGM
Write:
Reset: 0 0 0 0 0 0 0 0
$103C
Highest Priority I Bit Interrupt and
Miscellaneous Register (HPRIO)
See page 41.
Read:
RBOOT SMOD MDA IRV(NE) PSEL3 PSEL2 PSEL1 PSEL0
Write:
Reset: 0 0 0 0 0 1 1 0
$103D
RAM and I/O Mapping Register
(INIT)
See page 45.
Read:
RAM3 RAM2 RAM1 RAM0 REG3 REG2 REG1 REG0
Write:
Reset: 0 0 0 0 0 0 0 1
Addr. Register Name Bit 7 6 5 4 3 2 1 Bit 0
= Unimplemented R = Reserved U = Unaffected
I = Indeterminate after reset
Figure 2-7. Register and Control Bit Assignments (Sheet 5 of 6)
Memory Map
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 39
2.3.1 RAM and Input/Output Mapping
Hardware priority is built into RAM and I/O mapping. Registers have priority over RAM and RAM has
priority over ROM. When a lower priority resource is mapped at the same location as a higher priority
resource, a read/write of a location results in a read/write of the higher priority resource only. For example,
if both the register block and the RAM are mapped to the same location, only the register block will be
accessed. If RAM and ROM are located at the same position, RAM has priority.
The fully static RAM can be used to store instructions, variables, and temporary data. The direct
addressing mode can access RAM locations using a 1-byte address operand, saving program memory
space and execution time, depending on the application.
RAM contents can be preserved during periods of processor inactivity by two methods, both of which
reduce power consumption. They are:
1. In the software-based stop mode, the clocks are stopped while VDD powers the MCU. Because
power supply current is directly related to operating frequency in CMOS integrated circuits, only a
very small amount of leakage exists when the clocks are stopped.
2. In the second method, the MODB/VSTBY pin can supply RAM power from a battery backup or from
a second power supply. Figure 2-8 shows a typical standby voltage circuit for a standard 5-volt
device. Adjustments to the circuit must be made for devices that operate at lower voltages. Using
the MODB/VSTBY pin may require external hardware, but can be justified when a significant amount
of external circuitry is operating from VDD. If VSTBY is used to maintain RAM contents, reset must
be held low whenever VDD is below normal operating level. Refer to Chapter 5 Resets and
Interrupts.
$103E Reserved R R R R R R R R
$103F
System Configuration Register
(CONFIG)
See page 43.
Read:
NOSEC NOCOP ROMON EEON
Write:
Reset: 0 0 0 0 U U 1 U
$103F
System Configuration Register
(CONFIG)(3)
See page 43.
Read:
EE3 EE2 EE1 EE0 NOSEC NOCOP EEON
Write:
Reset: 1 1 1 1 U U 1 1
1. Can be written only once in first 64 cycles out of reset in normal modes or at any time during special modes.
2. MC68HC711E9 only
3. MC68HC811E2 only
Addr. Register Name Bit 7 6 5 4 3 2 1 Bit 0
= Unimplemented R = Reserved U = Unaffected
I = Indeterminate after reset
Figure 2-7. Register and Control Bit Assignments (Sheet 6 of 6)
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
40 Freescale Semiconductor
Figure 2-8. RAM Standby MODB/VSTBY Connections
The bootloader program is contained in the internal bootstrap ROM. This ROM, which appears as internal
memory space at locations $BF00–$BFFF, is enabled only if the MCU is reset in special bootstrap mode.
In expanded modes, the ROM/EPROM/OTPROM (if present) is enabled out of reset and located at the
top of the memory map if the ROMON bit in the CONFIG register is set. ROM or EPROM is enabled out
of reset in single-chip and bootstrap modes, regardless of the state of ROMON.
For devices with 512 bytes of EEPROM, the EEPROM is located at $B600–$B7FF and has the same read
cycle time as the internal ROM. The 512 bytes of EEPROM cannot be remapped to other locations.
For the MC68HC811E2, EEPROM is located at $F800–$FFFF and can be remapped to any 4-Kbyte
boundary. EEPROM mapping control bits (EE[3:0] in CONFIG) determine the location of the 2048 bytes
of EEPROM and are present only on the MC68HC811E2. Refer to 2.3.3.1 System Configuration Register
for a description of the MC68HC811E2 CONFIG register.
EEPROM can be programmed or erased by software and an on-chip charge pump, allowing EEPROM
changes using the single VDD supply.
2.3.2 Mode Selection
The four mode variations are selected by the logic states of the MODA and MODB pins during reset. The
MODA and MODB logic levels determine the logic state of SMOD and the MDA control bits in the highest
priority I-bit interrupt and miscellaneous (HPRIO) register.
After reset is released, the mode select pins no longer influence the MCU operating mode. In single-chip
operating mode, the MODA pin is connected to a logic level 0. In expanded mode, MODA is normally
connected to VDD through a pullup resistor of 4.7 kΩ. The MODA pin also functions as the load instruction
register LIR pin when the MCU is not in reset. The open-drain active low LIR output pin drives low during
the first E cycle of each instruction. The MODB pin also functions as standby power input (VSTBY), which
allows RAM contents to be maintained in absence of VDD.
Refer to Table 2-1, which is a summary of mode pin operation, the mode control bits, and the four
operating modes.
4.7 k
MAX
690
VBATT
+
4.8-V
NiCd
VDD
VDD
VOUT
TO MODB/VSTBY
OF M68HC11
Memory Map
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 41
A normal mode is selected when MODB is logic 1 during reset. One of three reset vectors is fetched from
address $FFFA–$FFFF, and program execution begins from the address indicated by this vector. If
MODB is logic 0 during reset, the special mode reset vector is fetched from addresses $BFFA–$BFFF,
and software has access to special test features. Refer to Chapter 5 Resets and Interrupts.
RBOOT — Read Bootstrap ROM Bit
Valid only when SMOD is set (bootstrap or special test mode); can be written only in special modes
0 = Bootloader ROM disabled and not in map
1 = Bootloader ROM enabled and in map at $BE00–$BFFF
SMOD and MDA — Special Mode Select and Mode Select A Bits
The initial value of SMOD is the inverse of the logic level present on the MODB pin at the rising edge
of reset. The initial value of MDA equals the logic level present on the MODA pin at the rising edge of
reset. These two bits can be read at any time. They can be written anytime in special modes. MDA can
be written only once in normal modes. SMOD cannot be set once it has been cleared.
Table 2-1. Hardware Mode Select Summary
Input Levels
at Reset Mode
Control Bits in HPRIO
(Latched at Reset)
MODB MODA RBOOT SMOD MDA
1 0 Single chip 0 0 0
1 1 Expanded 0 0 1
00Bootstrap110
01Special test011
Address: $103C
Bit 7 6 5 4 3 2 1 Bit 0
Read:
RBOOT(1) SMOD(1) MDA(1) IRV(NE)(1) PSEL3 PSEL2 PSEL1 PSEL0
Write:
Resets:
Single chip:0000 0110
Expanded:00100110
Bootstrap:1100 0110
Test:0111 0110
1. The reset values depend on the mode selected at the RESET pin rising edge.
Figure 2-9. Highest Priority I-Bit Interrupt and Miscellaneous
Register (HPRIO)
Input Mode Latched at Reset
MODB MODA SMOD MDA
1 0 Single chip 0 0
1 1 Expanded 0 1
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
42 Freescale Semiconductor
IRV(NE) — Internal Read Visibility (Not E) Bit
IRVNE can be written once in any mode. In expanded modes, IRVNE determines whether IRV is on
or off. In special test mode, IRVNE is reset to 1. In all other modes, IRVNE is reset to 0. For the
MC68HC811E2, this bit is IRV and only controls the internal read visibility function.
0 = No internal read visibility on external bus
1 = Data from internal reads is driven out the external data bus.
In single-chip modes this bit determines whether the E clock drives out from the chip. For the
MC68HC811E2, this bit has no meaning or effect in single-chip and bootstrap modes.
0 = E is driven out from the chip.
1 = E pin is driven low. Refer to the following table.
PSEL[3:0] — Priority Select Bits
Refer to Chapter 5 Resets and Interrupts.
2.3.3 System Initialization
Registers and bits that control initialization and the basic operation of the MCU are protected against
writes except under special circumstances. Table 2-2 lists registers that can be written only once after
reset or that must be written within the first 64 cycles after reset.
0 0 Bootstrap 1 0
0 1 Special test 1 1
Mode IRVNE Out
of Reset
E Clock Out
of Reset
IRV Out
of Reset
IRVNE
Affects Only
IRVNE Can
Be Written
Single chip 0 On Off E Once
Expanded 0 On Off IRV Once
Bootstrap 0 On Off E Once
Special test 1 On On IRV Once
Table 2-2. Write Access Limited Registers
Operating
Mode
Register
Address Register Name Must be Written
in First 64 Cycles
Write
Anytime
SMOD = 0 $x024 Timer interrupt mask 2 (TMSK2) Bits [1:0], once only Bits [7:2]
$x035 Block protect register (BPROT) Clear bits, once only Set bits only
$x039 System configuration options (OPTION) Bits [5:4], bits [2:0], once only Bits [7:6], bit 3
$x03C Highest priority I-bit interrupt
and miscellaneous (HPRIO) See HPRIO description See HPRIO description
$x03D RAM and I/O map register (INIT) Yes, once only —
SMOD = 1 $x024 Timer interrupt mask 2 (TMSK2) — All, set or clear
$x035 Block protect register (BPROT) — All, set or clear
$x039 System configuration options (OPTION) — All, set or clear
$x03C Highest priority I-bit interrupt and
miscellaneous (HPRIO) See HPRIO description See HPRIO description
$x03D RAM and I/O map register (INIT) — All, set or clear
Memory Map
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 43
2.3.3.1 System Configuration Register
The system configuration register (CONFIG) consists of an EEPROM byte and static latches that control
the startup configuration of the MCU. The contents of the EEPROM byte are transferred into static
working latches during reset sequences. The operation of the MCU is controlled directly by these latches
and not by CONFIG itself. In normal modes, changes to CONFIG do not affect operation of the MCU until
after the next reset sequence. When programming, the CONFIG register itself is accessed. When the
CONFIG register is read, the static latches are accessed. See 2.5.1 EEPROM and CONFIG
Programming and Erasure for information on modifying CONFIG.
To take full advantage of the MCU’s functionality, customers can program the CONFIG register in
bootstrap mode. This can be accomplished by setting the mode pins to logic 0 and downloading a small
program to internal RAM. For more information, Freescale application note AN1060 entitled M68HC11
Bootstrap Mode has been included at the back of this document. The downloadable talker will consist of:
• Bulk erase
• Byte programming
• Communication server
All of this functionality is provided by PCbug11 which can be found on the Freescale Web site at
http://www.freescale.com. For more information on using PCbug11 to program an E-series device,
Freescale engineering bulletin EB296 entitled Programming MC68HC711E9 Devices with PCbug11 and
the M68HC11EVBU has been included at the back of this document.
NOTE
The CONFIG register on the 68HC11 is an EEPROM cell and must be
programmed accordingly.
Operation of the CONFIG register in the MC68HC811E2 differs from other devices in the M68HC11 E
series. See Figure 2-10 and Figure 2-11.
Address: $103F
Bit 7654321Bit 0
Read:
NOSEC NOCOP ROMON EEON
Write:
Resets:
Single chip:
Bootstrap:
Expanded:
Test:
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
U
U
1
1
U
U(L)
U
U(L)
1
U
U
U
U
U
U
U
= Unimplemented
U indicates a previously programmed bit. U(L) indicates that the bit resets to the logic level held in the latch prior to reset,
but the function of COP is controlled by the DISR bit in TEST1 register.
Figure 2-10. System Configuration Register (CONFIG)
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
44 Freescale Semiconductor
EE[3:0] — EEPROM Mapping Bits
EE[3:0] apply only to MC68HC811E2 and allow the 2048 bytes of EEPROM to be remapped to any
4-Kbyte boundary. See Table 2-3.
Address: $103F
Bit 7654321Bit 0
Read:
EE3 EE2 EE1 EE0 NOSEC NOCOP EEON
Write:
Resets:
Single chip:
Bootstrap:
Expanded:
Test:
1
1
U
U
1
1
U
U
1
1
U
U
1
1
U
U
U
U
1
1
U
U(L)
U
U(L)
1
1
1
1
1
1
U
0
= Unimplemented
U indicates a previously programmed bit. U(L) indicates that the bit resets to the logic level held in the latch prior to reset,
but the function of COP is controlled by the DISR bit in TEST1 register.
Figure 2-11. MC68HC811E2 System Configuration Register (CONFIG)
Table 2-3. EEPROM Mapping
EE[3:0] EEPROM Location
0 0 0 0 $0800–$0FFF
0 0 0 1 $1800–$1FFF
0 0 1 0 $2800–$2FFF
0 0 1 1 $3800–$3FFF
0 1 0 0 $4800–$4FFF
0 1 0 1 $5800–$5FFF
0 1 1 0 $6800–$6FFF
0 1 1 1 $7800–$7FFF
1 0 0 0 $8800–$8FFF
1 0 0 1 $9800–$9FFF
1 0 1 0 $A800–$AFFF
1 0 1 1 $B800–$BFFF
1 1 0 0 $C800–$CFFF
1 1 0 1 $D800–$DFFF
1 1 1 0 $E800–$EFFF
1 1 1 1 $F800–$FFFF
Memory Map
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 45
NOSEC — Security Disable Bit
NOSEC is invalid unless the security mask option is specified before the MCU is manufactured. If the
security mask option is omitted NOSEC always reads 1. The enhanced security feature is available in
the MC68S711E9 MCU. The enhancement to the standard security feature protects the EPROM as
well as RAM and EEPROM.
0 = Security enabled
1 = Security disabled
NOCOP — COP System Disable Bit
Refer to Chapter 5 Resets and Interrupts.
1 = COP disabled
0 = COP enabled
ROMON — ROM/EPROM/OTPROM Enable Bit
When this bit is 0, the ROM or EPROM is disabled and that memory space becomes externally
addressed. In single-chip mode, ROMON is forced to 1 to enable ROM/EPROM regardless of the state
of the ROMON bit.
0 = ROM disabled from the memory map
1 = ROM present in the memory map
EEON — EEPROM Enable Bit
When this bit is 0, the EEPROM is disabled and that memory space becomes externally addressed.
0 = EEPROM removed from the memory map
1 = EEPROM present in the memory map
2.3.3.2 RAM and I/O Mapping Register
The internal registers used to control the operation of the MCU can be relocated on 4-Kbyte boundaries
within the memory space with the use of the RAM and I/O mapping register (INIT). This 8-bit
special-purpose register can change the default locations of the RAM and control registers within the
MCU memory map. It can be written only once within the first 64 E-clock cycles after a reset in normal
modes, and then it becomes a read-only register.
RAM[3:0] — RAM Map Position Bits
These four bits, which specify the upper hexadecimal digit of the RAM address, control position of RAM
in the memory map. RAM can be positioned at the beginning of any 4-Kbyte page in the memory map.
It is initialized to address $0000 out of reset. Refer to Table 2-4.
REG[3:0] — 64-Byte Register Block Position
These four bits specify the upper hexadecimal digit of the address for the 64-byte block of internal
registers. The register block, positioned at the beginning of any 4-Kbyte page in the memory map, is
initialized to address $1000 out of reset. Refer to Table 2-5.
Address: $103D
Bit 7654321Bit 0
Read:
RAM3 RAM2 RAM1 RAM0 REG3 REG2 REG1 REG0
Write:
Reset: 00000001
Figure 2-12. RAM and I/O Mapping Register (INIT)
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
46 Freescale Semiconductor
2.3.3.3 System Configuration Options Register
The 8-bit, special-purpose system configuration options register (OPTION) sets internal system
configuration options during initialization. The time protected control bits, IRQE, DLY, and CR[1:0], can
be written only once after a reset and then they become read-only. This minimizes the possibility of any
accidental changes to the system configuration.
ADPU — Analog-to-Digital Converter Power-Up Bit
Refer to Chapter 3 Analog-to-Digital (A/D) Converter.
CSEL — Clock Select Bit
Selects alternate clock source for on-chip EEPROM charge pump. Refer to 2.5.1 EEPROM and
CONFIG Programming and Erasure for more information on EEPROM use.
CSEL also selects the clock source for the A/D converter, a function discussed in Chapter 3
Analog-to-Digital (A/D) Converter.
Table 2-4. RAM Mapping Table 2-5. Register Mapping
RAM[3:0] Address REG[3:0] Address
0000 $0000–$0xFF 0000 $0000–$003F
0001 $1000–$1xFF 0001 $1000–$103F
0010 $2000–$2xFF 0010 $2000–$203F
0011 $3000–$3xFF 0011 $3000–$303F
0100 $4000–$4xFF 0100 $4000–$403F
0101 $5000–$5xFF 0101 $5000–$503F
0110 $6000–$6xFF 0110 $6000–$603F
0111 $7000–$7xFF 0111 $7000–$703F
1000 $8000–$8xFF 1000 $8000–$803F
1001 $9000–$9xFF 1001 $9000–$903F
1010 $A000–$AxFF 1010 $A000–$A03F
1011 $B000–$BxFF 1011 $B000–$B03F
1100 $C000–$CxFF 1100 $C000–$C03F
1101 $D000–$DxFF 1101 $D000–$D03F
1110 $E000–$ExFF 1110 $E000–$E03F
1111 $F000–$FxFF 1111 $F000–$F03F
Address: $1039
Bit 7654321Bit 0
Read:
ADPU CSEL IRQE(1) DLY(1) CME CR1(1) CR0(1)
Write:
Reset: 00010000
1. Can be written only once in first 64 cycles out of reset in normal modes or at any time during
special modes.
= Unimplemented
Figure 2-13. System Configuration Options Register (OPTION)
EPROM/OTPROM
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 47
IRQE — Configure IRQ for Edge-Sensitive Only Operation Bit
Refer to Chapter 5 Resets and Interrupts.
DLY — Enable Oscillator Startup Delay Bit
0 = The oscillator startup delay coming out of stop mode is bypassed and the MCU resumes
processing within about four bus cycles.
1 = A delay of approximately 4000 E-clock cycles is imposed as the MCU is started up from the stop
power-saving mode. This delay allows the crystal oscillator to stabilize.
CME — Clock Monitor Enable Bit
Refer to Chapter 5 Resets and Interrupts.
Bit 2 — Not implemented
Always reads 0
CR[1:0] — COP Timer Rate Select Bits
The internal E clock is divided by 215 before it enters the COP watchdog system. These control bits
determine a scaling factor for the watchdog timer. Refer to Chapter 5 Resets and Interrupts.
2.4 EPROM/OTPROM
Certain devices in the M68HC11 E series include on-chip EPROM/OTPROM. For instance:
• The MC68HC711E9 devices contain 12 Kbytes of on-chip EPROM (OTPROM in non-windowed
package).
• The MC68HC711E20 has 20 Kbytes of EPROM (OTPROM in non-windowed package).
• The MC68HC711E32 has 32 Kbytes of EPROM (OTPROM in non-windowed package).
Standard MC68HC71E9 and MC68HC711E20 devices are shipped with the EPROM/OTPROM contents
erased (all 1s). The programming operation programs zeros. Windowed devices must be erased using a
suitable ultraviolet light source before reprogramming. Depending on the light source, erasing can take
from 15 to 45 minutes.
Using the on-chip EPROM/OTPROM programming feature requires an external 12-volt nominal power
supply (VPPE). Normal programming is accomplished using the EPROM/OTPROM programming register
(PPROG).
PPROG is the combined EPROM/OTPROM and EEPROM programming register on all devices with
EPROM/OTPROM except the MC68HC711E20. For the MC68HC711E20, there is a separate register for
EPROM/OTPROM programming called the EPROG register.
As described in the following subsections, these two methods of programming and verifying EPROM are
possible:
1. Programming an individual EPROM address
2. Programming the EPROM with downloaded data
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
48 Freescale Semiconductor
2.4.1 Programming an Individual EPROM Address
• In this method, the MCU programs its own EPROM by controlling the PPROG register (EPROG in
MC68HC711E20). Use these procedures to program the EPROM through the MCU with:
• The ROMON bit set in the CONFIG register
• The 12-volt nominal programming voltage present on the XIRQ/VPPE pin
• The IRQ pin must be pulled high.
NOTE
Any operating mode can be used.
This example applies to all devices with EPROM/OTPROM except for the MC68HC711E20.
EPROG LDAB #$20
STAB $103B Set ELAT bit in (EPGM = 0) to enable
EPROM latches.
STAA $0,X Store data to EPROM address
LDAB #$21
STAB $103B Set EPGM bit with ELAT = 1 to enable
EPROM programming voltage
JSR DLYEP Delay 2–4 ms
CLR $103B Turn off programming voltage and set
to READ mode
This example applies only to MC68HC711E20.
EPROG LDAB #$20
STAB $1036 Set ELAT bit (EPGM = 0) to enable
EPROM latches.
STAA $0,X Store data to EPROM address
LDAB #$21
STAB $1036 Set EPGM bit with ELAT = 1 to enable
EPROM programming voltage
JSR DLYEP Delay 2–4 ms
CLR $1036 Turn off programming voltage and set
to READ mode
2.4.2 Programming the EPROM with Downloaded Data
When using this method, the EPROM is programmed by software while in the special test or bootstrap
modes. User-developed software can be uploaded through the SCI or a ROM-resident EPROM
programming utility can be used. The 12-volt nominal programming voltage must be present on the
XIRQ/VPPE pin. To use the resident utility, bootload a 3-byte program consisting of a single jump
instruction to $BF00. $BF00 is the starting address of a resident EPROM programming utility. The utility
program sets the X and Y index registers to default values, then receives programming data from an
external host, and puts it in EPROM. The value in IX determines programming delay time. The value in
IY is a pointer to the first address in EPROM to be programmed (default = $D000).
When the utility program is ready to receive programming data, it sends the host the $FF character. Then
it waits. When the host sees the $FF character, the EPROM programming data is sent, starting with the
first location in the EPROM array. After the last byte to be programmed is sent and the corresponding
verification data is returned, the programming operation is terminated by resetting the MCU.
For more information, Freescale application note AN1060 entitled M68HC11 Bootstrap Mode has been
included at the back of this document.
EPROM/OTPROM
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 49
2.4.3 EPROM and EEPROM Programming Control Register
The EPROM and EEPROM programming control register (PPROG) enables the EPROM programming
voltage and controls the latching of data to be programmed.
• For MC68HC711E9, PPROG is also the EEPROM programming control register.
• For the MC68HC711E20, EPROM programming is controlled by the EPROG register and
EEPROM programming is controlled by the PPROG register.
ODD — Program Odd Rows in Half of EEPROM (Test) Bit
Refer to 2.5 EEPROM.
EVEN — Program Even Rows in Half of EEPROM (Test) Bit
Refer to 2.5 EEPROM.
ELAT — EPROM/OTPROM Latch Control Bit
When ELAT = 1, writes to EPROM cause address and data to be latched and the EPROM/OTPROM
cannot be read. ELAT can be read any time. ELAT can be written any time except when EPGM = 1;
then the write to ELAT is disabled.
0 = EPROM address and data bus configured for normal reads
1 = EPROM address and data bus configured for programming
For the MC68HC711E9:
a. EPGM enables the high voltage necessary for both EEPROM and EPROM/OTPROM
programming.
b. ELAT and EELAT are mutually exclusive and cannot both equal 1.
BYTE — Byte/Other EEPROM Erase Mode Bit
Refer to 2.5 EEPROM.
ROW — Row/All EEPROM Erase Mode Bit
Refer to 2.5 EEPROM.
ERASE — Erase Mode Select Bit
Refer to 2.5 EEPROM.
EELAT — EEPROM Latch Control Bit
Refer to 2.5 EEPROM.
EPGM —EPROM/OTPROM/EEPROM Programming Voltage Enable Bit
EPGM can be read any time and can be written only when ELAT = 1 (for EPROM/OTPROM
programming) or when EELAT = 1 (for EEPROM programming).
0 = Programming voltage to EPROM/OTPROM/EEPROM array disconnected
1 = Programming voltage to EPROM/OTPROM/EEPROM array connected
Address: $103B
Bit 7654321Bit 0
Read:
ODD EVEN ELAT(1) BYTE ROW ERASE EELAT EPGM
Write:
Reset: 00000000
1. MC68HC711E9 only
Figure 2-14. EPROM and EEPROM Programming
Control Register (PPROG)
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
50 Freescale Semiconductor
MBE — Multiple-Byte Programming Enable Bit
When multiple-byte programming is enabled, address bit 5 is considered a don’t care so that bytes with
address bit 5 = 0 and address bit 5 = 1 both get programmed. MBE can be read in any mode and
always reads 0 in normal modes. MBE can be written only in special modes.
0 = EPROM array configured for normal programming
1 = Program two bytes with the same data
Bit 6 — Unimplemented
Always reads 0
ELAT — EPROM/OTPROM Latch Control Bit
When ELAT = 1, writes to EPROM cause address and data to be latched and the EPROM/OTPROM
cannot be read. ELAT can be read any time. ELAT can be written any time except when PGM = 1; then
the write to ELAT is disabled.
0 = EPROM/OTPROM address and data bus configured for normal reads
1 = EPROM/OTPROM address and data bus configured for programming
EXCOL — Select Extra Columns Bit
0 = User array selected
1 = User array is disabled and extra columns are accessed at bits [7:0]. Addresses use bits [13:5]
and bits [4:0] are don’t care. EXCOL can be read and written only in special modes and always
returns 0 in normal modes.
EXROW — Select Extra Rows Bit
0 = User array selected
1 = User array is disabled and two extra rows are available. Addresses use bits [7:0] and bits [13:8]
are don’t care. EXROW can be read and written only in special modes and always returns 0 in
normal modes.
T[1:0] — EPROM Test Mode Select Bits
These bits allow selection of either gate stress or drain stress test modes. They can be read and written
only in special modes and always read 0 in normal modes.
Address: $1036
Bit 7654321Bit 0
Read:
MBE ELAT EXCOL EXROW T1 T0 PGM
Write:
Reset: 00000000
= Unimplemented
Figure 2-15. MC68HC711E20 EPROM Programming
Control Register (EPROG)
T1 T0 Function Selected
0 0 Normal mode
01 Reserved
1 0 Gate stress
1 1 Drain stress
EEPROM
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 51
PGM — EPROM Programming Voltage Enable Bit
PGM can be read any time and can be written only when ELAT = 1.
0 = Programming voltage to EPROM array disconnected
1 = Programming voltage to EPROM array connected
2.5 EEPROM
Some E-series devices contain 512 bytes of on-chip EEPROM. The MC68HC811E2 contains 2048 bytes
of EEPROM with selectable base address. All E-series devices contain the EEPROM-based CONFIG
register.
2.5.1 EEPROM and CONFIG Programming and Erasure
The erased state of an EEPROM bit is 1. During a read operation, bit lines are precharged to 1. The
floating gate devices of programmed bits conduct and pull the bit lines to 0. Unprogrammed bits remain
at the precharged level and are read as ones. Programming a bit to 1 causes no change. Programming
a bit to 0 changes the bit so that subsequent reads return 0.
When appropriate bits in the BPROT register are cleared, the PPROG register controls programming and
erasing the EEPROM. The PPROG register can be read or written at any time, but logic enforces defined
programming and erasing sequences to prevent unintentional changes to EEPROM data. When the
EELAT bit in the PPROG register is cleared, the EEPROM can be read as if it were a ROM.
The on-chip charge pump that generates the EEPROM programming voltage from VDD uses MOS
capacitors, which are relatively small in value. The efficiency of this charge pump and its drive capability
are affected by the level of VDD and the frequency of the driving clock. The load depends on the number
of bits being programmed or erased and capacitances in the EEPROM array.
The clock source driving the charge pump is software selectable. When the clock select (CSEL) bit in the
OPTION register is 0, the E clock is used; when CSEL is 1, an on-chip resistor-capacitor (RC) oscillator
is used.
The EEPROM programming voltage power supply voltage to the EEPROM array is not enabled until there
has been a write to PPROG with EELAT set and PGM cleared. This must be followed by a write to a valid
EEPROM location or to the CONFIG address, and then a write to PPROG with both the EELAT and
EPGM bits set. Any attempt to set both EELAT and EPGM during the same write operation results in
neither bit being set.
2.5.1.1 Block Protect Register
This register prevents inadvertent writes to both the CONFIG register and EEPROM. The active bits in
this register are initialized to 1 out of reset and can be cleared only during the first 64 E-clock cycles after
reset in the normal modes. When these bits are cleared, the associated EEPROM section and the
CONFIG register can be programmed or erased. EEPROM is only visible if the EEON bit in the CONFIG
register is set. The bits in the BPROT register can be written to 1 at any time to protect EEPROM and the
CONFIG register. In test or bootstrap modes, write protection is inhibited and BPROT can be written
repeatedly. Address ranges for protected areas of EEPROM differ significantly for the MC68HC811E2.
Refer to Figure 2-16.
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
52 Freescale Semiconductor
Bits [7:5] — Unimplemented
Always read 0
PTCON — Protect CONFIG Register Bit
0 = CONFIG register can be programmed or erased normally.
1 = CONFIG register cannot be programmed or erased.
BPRT[3:0] — Block Protect Bits for EEPROM
When set, these bits protect a block of EEPROM from being programmed or electronically erased.
Ultraviolet light, however, can erase the entire EEPROM contents regardless of BPRT[3:0] (windowed
packages only). Refer to Table 2-6 and Table 2-7.
When cleared, BPRT[3:0] allow programming and erasure of the associated block.
Address: $1035
Bit 7654321Bit 0
Read:
PTCON BPRT3 BPRT2 BPRT1 BPRT0
Write:
Reset: 00011111
= Unimplemented
Figure 2-16. Block Protect Register (BPROT)
Table 2-6. EEPROM Block Protect
Bit Name Block Protected Block Size
BPRT0 $B600–$B61F 32 bytes
BPRT1 $B620–$B65F 64 bytes
BPRT2 $B660–$B6DF 128 bytes
BPRT3 $B6E0–$B7FF 288 bytes
Table 2-7. EEPROM Block Protect in MC68HC811E2 MCUs
Bit Name Block Protected Block Size
BPRT0 $x800–$x9FF(1)
1. x is determined by the value of EE[3:0] in CONFIG register. Refer to Figure
2-13.
512 bytes
BPRT1 $xA00–$xBFF(1) 512 bytes
BPRT2 $xC00–$xDFF(1) 512 bytes
BPRT3 $xE00–$xFFF(1) 512 bytes
EEPROM
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 53
2.5.1.2 EPROM and EEPROM Programming Control Register
The EPROM and EEPROM programming control register (PPROG) selects and controls the EEPROM
programming function. Bits in PPROG enable the programming voltage, control the latching of data to be
programmed, and select the method of erasure (for example, byte, row, etc.).
ODD — Program Odd Rows in Half of EEPROM (Test) Bit
EVEN — Program Even Rows in Half of EEPROM (Test) Bit
ELAT — EPROM/OTPROM Latch Control Bit
For the MC68HC711E9, EPGM enables the high voltage necessary for both EPROM/OTPROM and
EEPROM programming.
For MC68HC711E9, ELAT and EELAT are mutually exclusive and cannot both equal 1.
0 = EPROM address and data bus configured for normal reads
1 = EPROM address and data bus configured for programming
BYTE — Byte/Other EEPROM Erase Mode Bit
This bit overrides the ROW bit.
0 = Row or bulk erase
1 = Erase only one byte
ROW — Row/All EEPROM Erase Mode Bit
If BYTE is 1, ROW has no meaning.
0 = Bulk erase
1 = Row erase
ERASE — Erase Mode Select Bit
0 = Normal read or program mode
1 = Erase mode
EELAT — EEPROM Latch Control Bit
0 = EEPROM address and data bus configured for normal reads and cannot be programmed
1 = EEPROM address and data bus configured for programming or erasing and cannot be read
Address: $103B
Bit 7654321Bit 0
Read:
ODD EVEN ELAT(1) BYTE ROW ERASE EELAT EPGM
Write:
Reset: 00000000
1. MC68HC711E9 only
Figure 2-17. EPROM and EEPROM Programming
Control Register (PPROG)
Table 2-8. EEPROM Erase
BYTE ROW Action
0 0 Bulk erase (entire array)
0 1 Row erase (16 bytes)
1 0 Byte erase
1 1 Byte erase
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
54 Freescale Semiconductor
EPGM — EPROM/OTPROM/EEPROM Programming Voltage Enable Bit
0 = Programming voltage to EEPROM array switched off
1 = Programming voltage to EEPROM array switched on
During EEPROM programming, the ROW and BYTE bits of PPROG are not used. If the frequency of the
E clock is 1 MHz or less, set the CSEL bit in the OPTION register. Recall that 0s must be erased by a
separate erase operation before programming. The following examples of how to program an EEPROM
byte assume that the appropriate bits in BPROT are cleared.
PROG LDAB #$02 EELAT = 1
STAB $103B Set EELAT bit
STAA $XXXX Store data to EEPROM address
(for valid EEPROM address see memory
map for each device)
LDAB #$03 EELAT = 1, EPGM = 1
STAB $103B Turn on programming voltage
JSR DLY10 Delay 10 ms
CLR $103B Turn off high voltage and set
to READ mode
2.5.1.3 EEPROM Bulk Erase
This is an example of how to bulk erase the entire EEPROM. The CONFIG register is not affected in this
example.
BULKE LDAB #$06 EELAT = 1, ERASE = 1
STAB $103B Set to BULK erase mode
STAA $XXXX Store data to any EEPROM address (for
valid EEPROM address see memory map
for each device)
LDAB #$07 EELAT = 1, EPGM = 1, ERASE = 1
STAB $103B Turn on high voltage
JSR DLY10 Delay 10 ms
CLR $103B Turn off high voltage and set
to READ mode
2.5.1.4 EEPROM Row Erase
This example shows how to perform a fast erase of large sections of EEPROM.
ROWE LDAB #$0E ROW = 1, ERASE = 1, EELAT = 1
STAB $103B Set to ROW erase mode
STAB 0,X Write any data to any address in ROW
LDAB #$0F ROW = 1, ERASE = 1, EELAT = 1, EPGM = 1
STAB $103B Turn on high voltage
JSR DLY10 Delay 10 ms
CLR $103B Turn off high voltage and set
to READ mode
EEPROM
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 55
2.5.1.5 EEPROM Byte Erase
This is an example of how to erase a single byte of EEPROM.
BYTEE LDAB #$16 BYTE = 1, ERASE = 1, EELAT = 1
STAB $103B Set to BYTE erase mode
STAB 0,X Write any data to address to be erased
LDAB #$17 BYTE = 1, ERASE = 1, EELAT = 1,
EPGM = 1
STAB $103B Turn on high voltage
JSR DLY10 Delay 10 ms
CLR $103B Turn off high voltage and set
to READ mode
2.5.1.6 CONFIG Register Programming
Because the CONFIG register is implemented with EEPROM cells, use EEPROM procedures to erase
and program this register. The procedure for programming is the same as for programming a byte in the
EEPROM array, except that the CONFIG register address is used. CONFIG can be programmed or
erased (including byte erase) while the MCU is operating in any mode, provided that PTCON in BPROT
is clear.
To change the value in the CONFIG register, complete this procedure.
1. Erase the CONFIG register.
2. Program the new value to the CONFIG address.
3. Initiate reset.
NOTE
Do not initiate a reset until the procedure is complete.
2.5.2 EEPROM Security
The optional security feature, available only on ROM-based MCUs, protects the EEPROM and RAM
contents from unauthorized access. A program, or a key portion of a program, can be protected against
unauthorized duplication. To accomplish this, the protection mechanism restricts operation of protected
devices to the single-chip modes. This prevents the memory locations from being monitored externally
because single-chip modes do not allow visibility of the internal address and data buses. Resident
programs, however, have unlimited access to the internal EEPROM and RAM and can read, write, or
transfer the contents of these memories.
An enhanced security feature which protects EPROM contents, RAM, and EEPROM from unauthorized
accesses is available in MC68S711E9. Refer to Chapter 11 Ordering Information and Mechanical
Specifications for the exact part number.
For further information, these engineering bulletins have been included at the back of this data book:
• EB183 — Enabling the Security Feature on the MC68HC711E9 Devices with PCbug11 on the
M68HC711E9PGMR
• EB188 — Enabling the Security Feature on M68HC811E2 Devices with PCbug11 on the
M68HC711E9PGMR
Operating Modes and On-Chip Memory
M68HC11E Family Data Sheet, Rev. 5.1
56 Freescale Semiconductor
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 57
Chapter 3
Analog-to-Digital (A/D) Converter
3.1 Introduction
The analog-to-digital (A/D) system, a successive approximation converter, uses an all-capacitive charge
redistribution technique to convert analog signals to digital values.
3.2 Overview
The A/D system is an 8-channel, 8-bit, multiplexed-input converter. The converter does not require
external sample and hold circuits because of the type of charge redistribution technique used. A/D
converter timing can be synchronized to the system E clock or to an internal resistor capacitor (RC)
oscillator.
The A/D converter system consists of four functional blocks: multiplexer, analog converter, digital control,
and result storage. Refer to Figure 3-1.
3.2.1 Multiplexer
The multiplexer selects one of 16 inputs for conversion. Input selection is controlled by the value of bits
CD:CA in the ADCTL register. The eight port E pins are fixed-direction analog inputs to the multiplexer,
and additional internal analog signal lines are routed to it.
Port E pins also can be used as digital inputs. Digital reads of port E pins are not recommended during
the sample portion of an A/D conversion cycle, when the gate signal to the N-channel input gate is on.
Because no P-channel devices are directly connected to either input pins or reference voltage pins,
voltages above VDD do not cause a latchup problem, although current should be limited according to
maximum ratings. Refer to Figure 3-2, which is a functional diagram of an input pin.
3.2.2 Analog Converter
Conversion of an analog input selected by the multiplexer occurs in this block. It contains a
digital-to-analog capacitor (DAC) array, a comparator, and a successive approximation register (SAR).
Each conversion is a sequence of eight comparison operations, beginning with the most significant bit
(MSB). Each comparison determines the value of a bit in the successive approximation register.
The DAC array performs two functions. It acts as a sample and hold circuit during the entire conversion
sequence and provides comparison voltage to the comparator during each successive comparison.
The result of each successive comparison is stored in the SAR. When a conversion sequence is
complete, the contents of the SAR are transferred to the appropriate result register.
A charge pump provides switching voltage to the gates of analog switches in the multiplexer. Charge
pump output must stabilize between 7 and 8 volts within up to 100 µs before the converter can be used.
The charge pump is enabled by the ADPU bit in the OPTION register.
Analog-to-Digital (A/D) Converter
M68HC11E Family Data Sheet, Rev. 5.1
58 Freescale Semiconductor
Figure 3-1. A/D Converter Block Diagram
Figure 3-2. Electrical Model of an A/D Input Pin (Sample Mode)
8-BIT CAPACITIVE DAC
WITH SAMPLE AND HOLD
SUCCESSIVE APPROXIMATION
REGISTER AND CONTROL
RESULT
PE0
AN0
PE1
AN1
PE2
AN2
PE3
AN3
PE4
AN4
PE5
AN5
PE6
AN6
PE7
AN7
ANALOG
MUX
VRH
VRl
ADCTL A/D CONTROL
CCF
SCAN
MULT
CD
CC
CB
CA
INTERNAL
DATA BUS
ADR1 A/D RESULT 1 ADR2 A/D RESULT 2 ADR3 A/D RESULT 3 ADR4 A/D RESULT 4
RESULT REGISTER INTERFACE
DIFFUSION/POLY
< 2 pF
COUPLER
400 nA
JUNCTION
LEAKAGE
+ ~20 V
– ~0.7 V
*
* THIS ANALOG SWITCH IS CLOSED ONLY DURING THE 12-CYCLE SAMPLE TIME.
VRL
INPUT
+ ~12V
– ~0.7V
PROTECTION
DEVICE
ð 4 kΩ
DUMMY N-CHANNEL
OUTPUT DEVICE
ANALOG
INPUT
PIN
~ 20 pF
DAC
CAPACITANCE
Overview
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 59
3.2.3 Digital Control
All A/D converter operations are controlled by bits in register ADCTL. In addition to selecting the analog
input to be converted, ADCTL bits indicate conversion status and control whether single or continuous
conversions are performed. Finally, the ADCTL bits determine whether conversions are performed on
single or multiple channels.
3.2.4 Result Registers
Four 8-bit registers ADR[4:1] store conversion results. Each of these registers can be accessed by the
processor in the CPU. The conversion complete flag (CCF) indicates when valid data is present in the
result registers. The result registers are written during a portion of the system clock cycle when reads do
not occur, so there is no conflict.
3.2.5 A/D Converter Clocks
The CSEL bit in the OPTION register selects whether the A/D converter uses the system E clock or an
internal RC oscillator for synchronization. When E-clock frequency is below 750 kHz, charge leakage in
the capacitor array can cause errors, and the internal oscillator should be used. When the RC clock is
used, additional errors can occur because the comparator is sensitive to the additional system clock
noise.
3.2.6 Conversion Sequence
A/D converter operations are performed in sequences of four conversions each. A conversion sequence
can repeat continuously or stop after one iteration. The conversion complete flag (CCF) is set after the
fourth conversion in a sequence to show the availability of data in the result registers. Figure 3-3 shows
the timing of a typical sequence. Synchronization is referenced to the system E clock.
Figure 3-3. A/D Conversion Sequence
032 64 96 128 — E CYCLES
SAMPLE ANALOG INPUT SUCCESSIVE APPROXIMATION SEQUENCE
MSB
4
CYCLES
BIT 6
2
CYC
BIT 5
2
CYC
BIT 4
2
CYC
BIT 3
2
CYC
BIT 2
2
CYC
BIT 1
2
CYC
LSB
2
CYC
2
CYC
END
REPEAT SEQUENCE, SCAN = 1
SET CC FLAG
CONVERT FIRST
CHANNEL, UPDATE
ADR1
CONVERT SECOND
CHANNEL, UPDATE
ADR2
CONVERT THIRD
CHANNEL, UPDATE
ADR3
CONVERT FOURTH
CHANNEL, UPDATE
ADR4
12 E CYCLES
WRITE TO ADCTL
E CLOCK
Analog-to-Digital (A/D) Converter
M68HC11E Family Data Sheet, Rev. 5.1
60 Freescale Semiconductor
3.3 A/D Converter Power-Up and Clock Select
Bit 7 of the OPTION register controls A/D converter power-up. Clearing ADPU removes power from and
disables the A/D converter system. Setting ADPU enables the A/D converter system. Stabilization of the
analog bias voltages requires a delay of as much as 100 µs after turning on the A/D converter. When the
A/D converter system is operating with the MCU E clock, all switching and comparator operations are
inherently synchronized to the main MCU clocks. This allows the comparator output to be sampled at
relatively quiet times during MCU clock cycles. Since the internal RC oscillator is asynchronous to the
MCU clock, there is more error attributable to internal system clock noise. A/D converter accuracy is
reduced slightly while the internal RC oscillator is being used (CSEL = 1).
ADPU — A/D Power-Up Bit
0 = A/D powered down
1 = A/D powered up
CSEL — Clock Select Bit
0 = A/D and EEPROM use system E clock.
1 = A/D and EEPROM use internal RC clock.
IRQE — Configure IRQ for Edge-Sensitive Only Operation
Refer to Chapter 5 Resets and Interrupts.
DLY — Enable Oscillator Startup Delay Bit
0 = The oscillator startup delay coming out of stop is bypassed and the MCU resumes processing
within about four bus cycles.
1 = A delay of approximately 4000 E-clock cycles is imposed as the MCU is started up from the stop
power-saving mode. This delay allows the crystal oscillator to stabilize.
CME — Clock Monitor Enable Bit
Refer to Chapter 5 Resets and Interrupts.
Bit 2 — Not implemented
Always reads 0
CR[1:0] — COP Timer Rate Select Bits
Refer to Chapter 5 Resets and Interrupts and Chapter 9 Timing Systems.
Address: $1039
Bit 7654321Bit 0
Read:
ADPU CSEL IRQE(1) DLY(1) CME CR1(1) CR0(1)
Write:
Reset:00010000
1. Can be written only once in first 64 cycles out of reset in normal modes or at any time in special modes
= Unimplemented
Figure 3-4. System Configuration Options Register (OPTION)
Conversion Process
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 61
3.4 Conversion Process
The A/D conversion sequence begins one E-clock cycle after a write to the A/D control/status register,
ADCTL. The bits in ADCTL select the channel and the mode of conversion.
An input voltage equal to VRL converts to $00 and an input voltage equal to VRH converts to $FF (full
scale), with no overflow indication. For ratiometric conversions of this type, the source of each analog
input should use VRH as the supply voltage and be referenced to VRL.
3.5 Channel Assignments
The multiplexer allows the A/D converter to select one of 16 analog signals. Eight of these channels
correspond to port E input lines to the MCU, four of the channels are internal reference points or test
functions, and four channels are reserved. Refer to Table 3-1.
3.6 Single-Channel Operation
The two types of single-channel operation are:
1. When SCAN = 0, the single selected channel is converted four consecutive times. The first result
is stored in A/D result register 1 (ADR1), and the fourth result is stored in ADR4. After the fourth
conversion is complete, all conversion activity is halted until a new conversion command is written
to the ADCTL register.
2. When SCAN = 1, conversions continue to be performed on the selected channel with the fifth
conversion being stored in register ADR1 (overwriting the first conversion result), the sixth
conversion overwriting ADR2, and so on.
Table 3-1. Converter Channel Assignments
Channel
Number
Channel
Signal
Result in ADRx
if MULT = 1
1 AN0 ADR1
2 AN1 ADR2
3 AN2 ADR3
4 AN3 ADR4
5 AN4 ADR1
6 AN5 ADR2
7 AN6 ADR3
8 AN7 ADR4
9 – 12 Reserved —
13 VRH(1)
1. Used for factory testing
ADR1
14 VRL(1) ADR2
15 (VRH)/2(1) ADR3
16 Reserved(1) ADR4
Analog-to-Digital (A/D) Converter
M68HC11E Family Data Sheet, Rev. 5.1
62 Freescale Semiconductor
3.7 Multiple-Channel Operation
The two types of multiple-channel operation are:
1. When SCAN = 0, a selected group of four channels is converted one time each. The first result is
stored in A/D result register 1 (ADR1), and the fourth result is stored in ADR4. After the fourth
conversion is complete, all conversion activity is halted until a new conversion command is written
to the ADCTL register.
2. When SCAN = 1, conversions continue to be performed on the selected group of channels with the
fifth conversion being stored in register ADR1 (replacing the earlier conversion result for the first
channel in the group), the sixth conversion overwriting ADR2, and so on.
3.8 Operation in Stop and Wait Modes
If a conversion sequence is in progress when either the stop or wait mode is entered, the conversion of
the current channel is suspended. When the MCU resumes normal operation, that channel is resampled
and the conversion sequence is resumed. As the MCU exits wait mode, the A/D circuits are stable and
valid results can be obtained on the first conversion. However, in stop mode, all analog bias currents are
disabled and it is necessary to allow a stabilization period when leaving stop mode. If stop mode is exited
with a delay (DLY = 1), there is enough time for these circuits to stabilize before the first conversion. If
stop mode is exited with no delay (DLY bit in OPTION register = 0), allow 10 ms for the A/D circuitry to
stabilize to avoid invalid results.
3.9 A/D Control/Status Register
All bits in this register can be read or written, except bit 7, which is a read-only status indicator, and bit 6,
which always reads as 0. Write to ADCTL to initiate a conversion. To quit a conversion in progress, write
to this register and a new conversion sequence begins immediately.
CCF — Conversion Complete Flag
A read-only status indicator, this bit is set when all four A/D result registers contain valid conversion
results. Each time the ADCTL register is overwritten, this bit is automatically cleared to 0 and a
conversion sequence is started. In the continuous mode, CCF is set at the end of the first conversion
sequence.
Bit 6 — Unimplemented
Always reads 0
SCAN — Continuous Scan Control Bit
Address: $1030
Bit 7654321Bit 0
Read: CCF
SCAN MULT CD CC CB CA
Write:
Reset: 0 0 Indeterminate after reset
= Unimplemented
Figure 3-5. A/D Control/Status Register (ADCTL)
A/D Control/Status Register
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 63
When this control bit is clear, the four requested conversions are performed once to fill the four result
registers. When this control bit is set, conversions are performed continuously with the result registers
updated as data becomes available.
MULT — Multiple Channel/Single Channel Control Bit
When this bit is clear, the A/D converter system is configured to perform four consecutive conversions
on the single channel specified by the four channel select bits CD:CA (bits [3:0] of the ADCTL register).
When this bit is set, the A/D system is configured to perform a conversion on each of four channels
where each result register corresponds to one channel.
NOTE
When the multiple-channel continuous scan mode is used, extra care is
needed in the design of circuitry driving the A/D inputs. The charge on the
capacitive DAC array before the sample time is related to the voltage on the
previously converted channel. A charge share situation exists between the
internal DAC capacitance and the external circuit capacitance. Although
the amount of charge involved is small, the rate at which it is repeated is
every 64 µs for an E clock of 2 MHz. The RC charging rate of the external
circuit must be balanced against this charge sharing effect to avoid errors
in accuracy. Refer to M68HC11 Reference Manual, Freescale document
order number M68HC11RM/AD, for further information.
CD:CA — Channel Selects D:A Bits
Refer to Table 3-2. When a multiple channel mode is selected (MULT = 1), the two least significant
channel select bits (CB and CA) have no meaning and the CD and CC bits specify which group of four
channels is to be converted.
Table 3-2. A/D Converter Channel Selection
Channel Select
Control Bits Channel Signal Result in ADRx
if MULT = 1
CD:CC:CB:CA
0000 AN0 ADR1
0001 AN1 ADR2
0010 AN2 ADR3
0011 AN3 ADR4
0100 AN4 ADR1
0101 AN5 ADR2
0110 AN6 ADR3
0111 AN7 ADR4
10XX Reserved —
1100 VRH(1)
1. Used for factory testing
ADR1
1101 VRL(1) ADR2
1110 (VRH)/2(1) ADR3
1111 Reserved(1) ADR4
Analog-to-Digital (A/D) Converter
M68HC11E Family Data Sheet, Rev. 5.1
64 Freescale Semiconductor
3.10 A/D Converter Result Registers
These read-only registers hold an 8-bit conversion result. Writes to these registers have no effect. Data
in the A/D converter result registers is valid when the CCF flag in the ADCTL register is set, indicating a
conversion sequence is complete. If conversion results are needed sooner, refer to Figure 3-3, which
shows the A/D conversion sequence diagram.
Register name: Analog-to-Digital Converter Result Register 1 Address: $1031
Bit 7654321Bit 0
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
Register name: Analog-to-Digital Converter Result Register 2 Address: $1032
Bit 7654321Bit 0
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
Register name: Analog-to-Digital Converter Result Register 3 Address: $1033
Bit 7654321Bit 0
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
Register name: Analog-to-Digital Converter Result Register 4 Address: $1034
Bit 7654321Bit 0
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
= Unimplemented
Figure 3-6. Analog-to-Digital Converter
Result Registers (ADR1–ADR4)
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 65
Chapter 4
Central Processor Unit (CPU)
4.1 Introduction
Features of the M68HC11 Family include:
• Central processor unit (CPU) architecture
• Data types
• Addressing modes
• Instruction set
• Special operations such as subroutine calls and interrupts
The CPU is designed to treat all peripheral, input/output (I/O), and memory locations identically as
addresses in the 64-Kbyte memory map. This is referred to as memory-mapped I/O. There are no special
instructions for I/O that are separate from those used for memory. This architecture also allows accessing
an operand from an external memory location with no execution time penalty.
4.2 CPU Registers
M68HC11 CPU registers are an integral part of the CPU and are not addressed as if they were memory
locations. The seven registers, discussed in the following paragraphs, are shown in Figure 4-1.
Figure 4-1. Programming Model
8-BIT ACCUMULATORS A & B
7070
15 0
AB
D
IX
IY
SP
PC
70
CVZNIHXS
OR 16-BIT DOUBLE ACCUMULATOR D
INDEX REGISTER X
INDEX REGISTER Y
STACK POINTER
PROGRAM COUNTER
CARRY/BORROW FROM MSB
OVERFLOW
ZERO
NEGATIVE
I-INTERRUPT MASK
HALF CARRY (FROM BIT 3)
X-INTERRUPT MASK
STOP DISABLE
CONDITION CODES
Central Processor Unit (CPU)
M68HC11E Family Data Sheet, Rev. 5.1
66 Freescale Semiconductor
4.2.1 Accumulators A, B, and D
Accumulators A and B are general-purpose 8-bit registers that hold operands and results of arithmetic
calculations or data manipulations. For some instructions, these two accumulators are treated as a single
double-byte (16-bit) accumulator called accumulator D. Although most instructions can use accumulators
A or B interchangeably, these exceptions apply:
• The ABX and ABY instructions add the contents of 8-bit accumulator B to the contents of 16-bit
register X or Y, but there are no equivalent instructions that use A instead of B.
• The TAP and TPA instructions transfer data from accumulator A to the condition code register or
from the condition code register to accumulator A. However, there are no equivalent instructions
that use B rather than A.
• The decimal adjust accumulator A (DAA) instruction is used after binary-coded decimal (BCD)
arithmetic operations, but there is no equivalent BCD instruction to adjust accumulator B.
• The add, subtract, and compare instructions associated with both A and B (ABA, SBA, and CBA)
only operate in one direction, making it important to plan ahead to ensure that the correct operand
is in the correct accumulator.
4.2.2 Index Register X (IX)
The IX register provides a 16-bit indexing value that can be added to the 8-bit offset provided in an
instruction to create an effective address. The IX register can also be used as a counter or as a temporary
storage register.
4.2.3 Index Register Y (IY)
The 16-bit IY register performs an indexed mode function similar to that of the IX register. However, most
instructions using the IY register require an extra byte of machine code and an extra cycle of execution
time because of the way the opcode map is implemented. Refer to 4.4 Opcodes and Operands for further
information.
4.2.4 Stack Pointer (SP)
The M68HC11 CPU has an automatic program stack. This stack can be located anywhere in the address
space and can be any size up to the amount of memory available in the system. Normally, the SP is
initialized by one of the first instructions in an application program. The stack is configured as a data
structure that grows downward from high memory to low memory. Each time a new byte is pushed onto
the stack, the SP is decremented. Each time a byte is pulled from the stack, the SP is incremented. At
any given time, the SP holds the 16-bit address of the next free location in the stack. Figure 4-2 is a
summary of SP operations.
When a subroutine is called by a jump-to-subroutine (JSR) or branch-to- subroutine (BSR) instruction, the
address of the instruction after the JSR or BSR is automatically pushed onto the stack, least significant
byte first. When the subroutine is finished, a return-from-subroutine (RTS) instruction is executed. The
RTS pulls the previously stacked return address from the stack and loads it into the program counter.
Execution then continues at this recovered return address.
When an interrupt is recognized, the current instruction finishes normally, the return address (the current
value in the program counter) is pushed onto the stack, all of the CPU registers are pushed onto the stack,
and execution continues at the address specified by the vector for the interrupt.
CPU Registers
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 67
At the end of the interrupt service routine, an return-from interrupt (RTI) instruction is executed. The RTI
instruction causes the saved registers to be pulled off the stack in reverse order. Program execution
resumes at the return address.
Certain instructions push and pull the A and B accumulators and the X and Y index registers and are often
used to preserve program context. For example, pushing accumulator A onto the stack when entering a
subroutine that uses accumulator A and then pulling accumulator A off the stack just before leaving the
subroutine ensures that the contents of a register will be the same after returning from the subroutine as
it was before starting the subroutine.
Figure 4-2. Stacking Operations
È SP–2
STACK
RTNH
SP–1
RTNL
SP
70
PC
MAIN PROGRAM
$9D = JSR
JSR, JUMP TO SUBROUTINE
dd
NEXT MAIN INSTR.
RTN
DIRECT
PC
MAIN PROGRAM
$AD = JSR
ff
NEXT MAIN INSTR.
RTN
INDEXED, X
PC
MAIN PROGRAM
$18 = PRE
ff
NEXT MAIN INSTR.
RTN
INDEXED, Y $AD = JSR
PC
MAIN PROGRAM
$BD = PRE
ll
NEXT MAIN INSTR.
RTN
INDEXED, Y hh
SP
STACK
CCR
SP+1
ACCB
SP+2
ACCA
SP+3
IXH
SP+4
IXL
SP+5
IYH
SP+6
IYL
SP+7
RTNH
SP+8
È SP+9
70
RTNL
PC
INTERRUPT ROUTINE
$3B = RTI
È SP–9
STACK
CCR
SP–8
ACCB
SP–7
ACCA
SP–6
IXH
SP–5
IXL
SP–4
IYH
SP–3
IYL
SP–2
RTNH
SP–1
SP
70
RTNL
PC
MAIN PROGRAM
$3F = SWI
PC
MAIN PROGRAM
$3E = WAI
SWI, SOFTWARE INTERRUPT
WAI, WAIT FOR INTERRUPT
RTI, RETURN FROM INTERRUPT
È SP–2
STACK
RTNH
SP–1
RTNL
SP
70
PC
MAIN PROGRAM
$8D = BSR
PC
MAIN PROGRAM
$39 = RTS
BSR, BRANCH TO SUBROUTINE
RTS, RETURN FROM
SUBROUTINE
SP
STACK
RTNH
SP+1
RTNL
È SP+2
70
LEGEND:
RTN = ADDRESS OF NEXT INSTRUCTION IN MAIN PROGRAM TO
BE EXECUTED UPON RETURN FROM SUBROUTINE
RTNH = MOST SIGNIFICANT BYTE OF RETURN ADDRESS
RTNL = LEAST SIGNIFICANT BYTE OF RETURN ADDRESS
È = STACK POINTER POSITION AFTER OPERATION IS COMPLETE
dd = 8-BIT DIRECT ADDRESS ($0000–$00FF) (HIGH BYTE ASSUMED
TO BE $00)
ff = 8-BIT POSITIVE OFFSET $00 (0) TO $FF (255) IS ADDED TO INDEX
hh = HIGH-ORDER BYTE OF 16-BIT EXTENDED ADDRESS
ll = LOW-ORDER BYTE OF 16-BIT EXTENDED ADDRESS
rr= SIGNED RELATIVE OFFSET $80 (–128) TO $7F (+127) (OFFSET
RELATIVE TO THE ADDRESS FOLLOWING THE MACHINE CODE
OFFSET BYTE)
Central Processor Unit (CPU)
M68HC11E Family Data Sheet, Rev. 5.1
68 Freescale Semiconductor
4.2.5 Program Counter (PC)
The program counter, a 16-bit register, contains the address of the next instruction to be executed. After
reset, the program counter is initialized from one of six possible vectors, depending on operating mode
and the cause of reset. See Table 4-1.
4.2.6 Condition Code Register (CCR)
This 8-bit register contains:
• Five condition code indicators (C, V, Z, N, and H),
• Two interrupt masking bits (IRQ and XIRQ)
• A stop disable bit (S)
In the M68HC11 CPU, condition codes are updated automatically by most instructions. For example, load
accumulator A (LDAA) and store accumulator A (STAA) instructions automatically set or clear the N, Z,
and V condition code flags. Pushes, pulls, add B to X (ABX), add B to Y (ABY), and transfer/exchange
instructions do not affect the condition codes. Refer to Table 4-2, which shows what condition codes are
affected by a particular instruction.
4.2.6.1 Carry/Borrow (C)
The C bit is set if the arithmetic logic unit (ALU) performs a carry or borrow during an arithmetic operation.
The C bit also acts as an error flag for multiply and divide operations. Shift and rotate instructions operate
with and through the carry bit to facilitate multiple-word shift operations.
4.2.6.2 Overflow (V)
The overflow bit is set if an operation causes an arithmetic overflow. Otherwise, the V bit is cleared.
4.2.6.3 Zero (Z)
The Z bit is set if the result of an arithmetic, logic, or data manipulation operation is 0. Otherwise, the Z
bit is cleared. Compare instructions do an internal implied subtraction and the condition codes, including
Z, reflect the results of that subtraction. A few operations (INX, DEX, INY, and DEY) affect the Z bit and
no other condition flags. For these operations, only = and ≠ conditions can be determined.
4.2.6.4 Negative (N)
The N bit is set if the result of an arithmetic, logic, or data manipulation operation is negative (MSB = 1).
Otherwise, the N bit is cleared. A result is said to be negative if its most significant bit (MSB) is a 1. A quick
way to test whether the contents of a memory location has the MSB set is to load it into an accumulator
and then check the status of the N bit.
Table 4-1. Reset Vector Comparison
Mode POR or RESET Pin Clock Monitor COP Watchdog
Normal $FFFE, F $FFFC, D $FFFA, B
Test or Boot $BFFE, F $BFFC, D $BFFA, B
Data Types
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 69
4.2.6.5 Interrupt Mask (I)
The interrupt request (IRQ) mask (I bit) is a global mask that disables all maskable interrupt sources.
While the I bit is set, interrupts can become pending, but the operation of the CPU continues uninterrupted
until the I bit is cleared. After any reset, the I bit is set by default and can only be cleared by a software
instruction. When an interrupt is recognized, the I bit is set after the registers are stacked, but before the
interrupt vector is fetched. After the interrupt has been serviced, a return-from-interrupt instruction is
normally executed, restoring the registers to the values that were present before the interrupt occurred.
Normally, the I bit is 0 after a return from interrupt is executed. Although the I bit can be cleared within an
interrupt service routine, "nesting" interrupts in this way should only be done when there is a clear
understanding of latency and of the arbitration mechanism. Refer to Chapter 5 Resets and Interrupts.
4.2.6.6 Half Carry (H)
The H bit is set when a carry occurs between bits 3 and 4 of the arithmetic logic unit during an ADD, ABA,
or ADC instruction. Otherwise, the H bit is cleared. Half carry is used during BCD operations.
4.2.6.7 X Interrupt Mask (X)
The XIRQ mask (X) bit disables interrupts from the XIRQ pin. After any reset, X is set by default and must
be cleared by a software instruction. When an XIRQ interrupt is recognized, the X and I bits are set after
the registers are stacked, but before the interrupt vector is fetched. After the interrupt has been serviced,
an RTI instruction is normally executed, causing the registers to be restored to the values that were
present before the interrupt occurred. The X interrupt mask bit is set only by hardware (RESET or XIRQ
acknowledge). X is cleared only by program instruction (TAP, where the associated bit of A is 0; or RTI,
where bit 6 of the value loaded into the CCR from the stack has been cleared). There is no hardware
action for clearing X.
4.2.6.8 STOP Disable (S)
Setting the STOP disable (S) bit prevents the STOP instruction from putting the M68HC11 into a
low-power stop condition. If the STOP instruction is encountered by the CPU while the S bit is set, it is
treated as a no-operation (NOP) instruction, and processing continues to the next instruction. S is set by
reset; STOP is disabled by default.
4.3 Data Types
The M68HC11 CPU supports four data types:
1. Bit data
2. 8-bit and 16-bit signed and unsigned integers
3. 16-bit unsigned fractions
4. 16-bit addresses
A byte is eight bits wide and can be accessed at any byte location. A word is composed of two consecutive
bytes with the most significant byte at the lower value address. Because the M68HC11 is an 8-bit CPU,
there are no special requirements for alignment of instructions or operands.
Central Processor Unit (CPU)
M68HC11E Family Data Sheet, Rev. 5.1
70 Freescale Semiconductor
4.4 Opcodes and Operands
The M68HC11 Family of microcontrollers uses 8-bit opcodes. Each opcode identifies a particular
instruction and associated addressing mode to the CPU. Several opcodes are required to provide each
instruction with a range of addressing capabilities. Only 256 opcodes would be available if the range of
values were restricted to the number able to be expressed in 8-bit binary numbers.
A 4-page opcode map has been implemented to expand the number of instructions. An additional byte,
called a prebyte, directs the processor from page 0 of the opcode map to one of the other three pages.
As its name implies, the additional byte precedes the opcode.
A complete instruction consists of a prebyte, if any, an opcode, and zero, one, two, or three operands.
The operands contain information the CPU needs for executing the instruction. Complete instructions can
be from one to five bytes long.
4.5 Addressing Modes
Six addressing modes can be used to access memory:
•Immediate
•Direct
• Extended
• Indexed
• Inherent
• Relative
These modes are detailed in the following paragraphs. All modes except inherent mode use an effective
address. The effective address is the memory address from which the argument is fetched or stored or
the address from which execution is to proceed. The effective address can be specified within an
instruction, or it can be calculated.
4.5.1 Immediate
In the immediate addressing mode, an argument is contained in the byte(s) immediately following the
opcode. The number of bytes following the opcode matches the size of the register or memory location
being operated on. There are 2-, 3-, and 4- (if prebyte is required) byte immediate instructions. The
effective address is the address of the byte following the instruction.
4.5.2 Direct
In the direct addressing mode, the low-order byte of the operand address is contained in a single byte
following the opcode, and the high-order byte of the address is assumed to be $00. Addresses $00–$FF
are thus accessed directly, using 2-byte instructions. Execution time is reduced by eliminating the
additional memory access required for the high-order address byte. In most applications, this
256-byte area is reserved for frequently referenced data. In M68HC11 MCUs, the memory map can be
configured for combinations of internal registers, RAM, or external memory to occupy these addresses.
Instruction Set
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 71
4.5.3 Extended
In the extended addressing mode, the effective address of the argument is contained in two bytes
following the opcode byte. These are 3-byte instructions (or 4-byte instructions if a prebyte is required).
One or two bytes are needed for the opcode and two for the effective address.
4.5.4 Indexed
In the indexed addressing mode, an 8-bit unsigned offset contained in the instruction is added to the value
contained in an index register (IX or IY). The sum is the effective address. This addressing mode allows
referencing any memory location in the 64-Kbyte address space. These are 2- to 5-byte instructions,
depending on whether or not a prebyte is required.
4.5.5 Inherent
In the inherent addressing mode, all the information necessary to execute the instruction is contained in
the opcode. Operations that use only the index registers or accumulators, as well as control instructions
with no arguments, are included in this addressing mode. These are
1- or 2-byte instructions.
4.5.6 Relative
The relative addressing mode is used only for branch instructions. If the branch condition is true, an 8-bit
signed offset included in the instruction is added to the contents of the program counter to form the
effective branch address. Otherwise, control proceeds to the next instruction. These are usually 2-byte
instructions.
4.6 Instruction Set
Refer to Table 4-2, which shows all the M68HC11 instructions in all possible addressing modes. For each
instruction, the table shows the operand construction, the number of machine code bytes, and execution
time in CPU E-clock cycles.
Central Processor Unit (CPU)
M68HC11E Family Data Sheet, Rev. 5.1
72 Freescale Semiconductor
Table 4-2. Instruction Set (Sheet 1 of 7)
Mnemonic Operation Description Addressing Instruction Condition Codes
Mode Opcode Operand Cycles S X H I N Z V C
ABA Add
Accumulators
A + B ⇒ AINH1B—2——∆—∆∆∆∆
ABX Add B to X IX + (00 : B) ⇒ IX INH 3A — 3 ————————
ABY Add B to Y IY + (00 : B) ⇒ IY INH 18 3A — 4 ————————
ADCA (opr) Add with Carry
to A
A + M + C ⇒ AA IMM
ADIR
AEXT
AIND,X
AIND,Y
89
99
B9
A9
18 A9
ii
dd
hh ll
ff
ff
2
3
4
4
5
—— ∆—∆∆∆∆
ADCB (opr) Add with Carry
to B
B + M + C ⇒ BB IMM
BDIR
BEXT
BIND,X
BIND,Y
C9
D9
F9
E9
18 E9
ii
dd
hh ll
ff
ff
2
3
4
4
5
—— ∆—∆∆∆∆
ADDA (opr) Add Memory to
A
A + M ⇒ A A IMM
ADIR
AEXT
AIND,X
AIND,Y
8B
9B
BB
AB
18 AB
ii
dd
hh ll
ff
ff
2
3
4
4
5
—— ∆—∆∆∆∆
ADDB (opr) Add Memory to
B
B + M ⇒ BBIMM
BDIR
BEXT
BIND,X
BIND,Y
CB
DB
FB
EB
18 EB
ii
dd
hh ll
ff
ff
2
3
4
4
5
—— ∆—∆∆∆∆
ADDD (opr) Add 16-Bit to D D + (M : M + 1) ⇒ DIMM
DIR
EXT
IND,X
IND,Y
C3
D3
F3
E3
18 E3
jj kk
dd
hh ll
ff
ff
4
5
6
6
7
———— ∆∆∆∆
ANDA (opr) AND A with
Memory
A • M ⇒ AA IMM
A DIR
A EXT
AIND,X
AIND,Y
84
94
B4
A4
18 A4
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆0—
ANDB (opr) AND B with
Memory
B • M ⇒ BBIMM
BDIR
BEXT
BIND,X
BIND,Y
C4
D4
F4
E4
18 E4
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆0—
ASL (opr) Arithmetic Shift
Left
EXT
IND,X
IND,Y
78
68
18 68
hh ll
ff
ff
6
6
7
———— ∆∆∆∆
ASLA Arithmetic Shift
Left A
A INH 48 — 2 ———— ∆∆∆∆
ASLB Arithmetic Shift
Left B
B INH 58 — 2 ———— ∆∆∆∆
ASLD Arithmetic Shift
Left D
INH 05 — 3 — — — — ∆∆∆∆
ASR Arithmetic Shift
Right
EXT
IND,X
IND,Y
77
67
18 67
hh ll
ff
ff
6
6
7
———— ∆∆∆∆
ASRA Arithmetic Shift
Right A
A INH 47 — 2 ———— ∆∆∆∆
ASRB Arithmetic Shift
Right B
B INH 57 — 2 ———— ∆∆∆∆
BCC (rel) Branch if Carry
Clear
? C = 0 REL 24 rr 3 ————————
BCLR (opr)
(msk)
Clear Bit(s) M • (mm) ⇒ M DIR
IND,X
IND,Y
15
1D
18 1D
dd mm
ff mm
ff mm
6
7
8
———— ∆∆0—
BCS (rel) Branch if Carry
Set
? C = 1 REL 25 rr 3 ————————
BEQ (rel) Branch if = Zero ? Z = 1 REL 27 rr 3 — — — — — — — —
BGE (rel) Branch if ∆ Zero ? N ⊕ V = 0 REL 2C rr 3 ————————
C
0
b7 b0
C
0
b7 b0
C
0
b7 b0
C
0
b7 b0AB
b7
b0
C
b7 b0
C
b7 b0
C
b7 b0
Instruction Set
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 73
BGT (rel) Branch if > Zero ? Z + (N ⊕ V) = 0 REL 2E rr 3 ————————
BHI (rel) Branch if
Higher
? C + Z = 0 REL 22 rr 3 ————————
BHS (rel) Branch if
Higher or Same
? C = 0 REL 24 rr 3 ————————
BITA (opr) Bit(s) Test A
with Memory
A • M A IMM
ADIR
AEXT
AIND,X
AIND,Y
85
95
B5
A5
18 A5
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆0—
BITB (opr) Bit(s) Test B
with Memory
B • M B IMM
BDIR
BEXT
BIND,X
BIND,Y
C5
D5
F5
E5
18 E5
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆0—
BLE (rel) Branch if ∆ Zero ? Z + (N ⊕ V) = 1 REL 2F rr 3 ————————
BLO (rel) Branch if Lower ? C = 1 REL 25 rr 3 ————————
BLS (rel) Branch if Lower
or Same
? C + Z = 1 REL 23 rr 3 ————————
BLT (rel) Branch if < Zero ? N ⊕ V = 1 REL 2D rr 3 ————————
BMI (rel) Branch if Minus ? N = 1 REL 2B rr 3 ————————
BNE (rel) Branch if not =
Zero
? Z = 0 REL 26 rr 3 ————————
BPL (rel) Branch if Plus ? N = 0 REL 2A rr 3 ————————
BRA (rel) Branch Always ? 1 = 1 REL 20 rr 3 ————————
BRCLR(opr)
(msk)
(rel)
Branch if
Bit(s) Clear
? M • mm = 0 DIR
IND,X
IND,Y
13
1F
18 1F
dd mm
rr
ff mm
rr
ff mm
rr
6
7
8
————————
BRN (rel) Branch Never ? 1 = 0 REL 21 rr 3 ————————
BRSET(opr)
(msk)
(rel)
Branch if Bit(s)
Set
? (M) • mm = 0 DIR
IND,X
IND,Y
12
1E
18 1E
dd mm
rr
ff mm
rr
ff mm
rr
6
7
8
————————
BSET (opr)
(msk)
Set Bit(s) M + mm ⇒ MDIR
IND,X
IND,Y
14
1C
18 1C
dd mm
ff mm
ff mm
6
7
8
———— ∆∆0—
BSR (rel) Branch to
Subroutine
See Figure 3–2 REL 8D rr 6 ————————
BVC (rel) Branch if
Overflow Clear
? V = 0 REL 28 rr 3 ————————
BVS (rel) Branch if
Overflow Set
? V = 1 REL 29 rr 3 ————————
CBA Compare A to B A – B INH 11 — 2 — — — — ∆∆∆∆
CLC Clear Carry Bit 0 ⇒ C INH 0C — 2 ——————— 0
CLI Clear Interrupt
Mask
0 ⇒ I INH 0E — 2 ——— 0 ————
CLR (opr) Clear Memory
Byte
0 ⇒ MEXT
IND,X
IND,Y
7F
6F
18 6F
hh ll
ff
ff
6
6
7
———— 0 1 0 0
CLRA Clear
Accumulator A
0 ⇒ A A INH 4F — 2 — — — — 0 1 0 0
CLRB Clear
Accumulator B
0 ⇒ B B INH 5F — 2 — — — — 0 1 0 0
CLV Clear Overflow
Flag
0 ⇒ V INH 0A — 2 —————— 0 —
CMPA (opr) Compare A to
Memory
A – M A IMM
ADIR
AEXT
AIND,X
AIND,Y
81
91
B1
A1
18 A1
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆∆∆
Table 4-2. Instruction Set (Sheet 2 of 7)
Mnemonic Operation Description Addressing Instruction Condition Codes
Mode Opcode Operand Cycles S X H I N Z V C
Central Processor Unit (CPU)
M68HC11E Family Data Sheet, Rev. 5.1
74 Freescale Semiconductor
CMPB (opr) Compare B to
Memory
B – M B IMM
BDIR
BEXT
BIND,X
BIND,Y
C1
D1
F1
E1
18 E1
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆∆∆
COM (opr) Ones
Complement
Memory Byte
$FF – M ⇒ MEXT
IND,X
IND,Y
73
63
18 63
hh ll
ff
ff
6
6
7
———— ∆∆01
COMA Ones
Complement
A
$FF – A ⇒ AA INH 43 — 2 ————∆∆01
COMB Ones
Complement
B
$FF – B ⇒ BB INH 53 — 2 ————∆∆01
CPD (opr) Compare D to
Memory 16-Bit
D – M : M + 1 IMM
DIR
EXT
IND,X
IND,Y
1A 83
1A 93
1A B3
1A A3
CD A3
jj kk
dd
hh ll
ff
ff
5
6
7
7
7
———— ∆∆∆∆
CPX (opr) Compare X to
Memory 16-Bit
IX – M : M + 1 IMM
DIR
EXT
IND,X
IND,Y
8C
9C
BC
AC
CD AC
jj kk
dd
hh ll
ff
ff
4
5
6
6
7
———— ∆∆∆∆
CPY (opr) Compare Y to
Memory 16-Bit
IY – M : M + 1 IMM
DIR
EXT
IND,X
IND,Y
18 8C
18 9C
18 BC
1A AC
18 AC
jj kk
dd
hh ll
ff
ff
5
6
7
7
7
———— ∆∆∆∆
DAA Decimal Adjust
A
Adjust Sum to BCD INH 19 — 2 — — — — ∆∆∆∆
DEC (opr) Decrement
Memory Byte
M – 1 ⇒ MEXT
IND,X
IND,Y
7A
6A
18 6A
hh ll
ff
ff
6
6
7
———— ∆∆∆—
DECA Decrement
Accumulator
A
A – 1 ⇒ AAINH 4A — 2————∆∆∆—
DECB Decrement
Accumulator
B
B – 1 ⇒ BBINH 5A — 2————∆∆∆—
DES Decrement
Stack Pointer
SP – 1 ⇒ SP INH 34 — 3 ————————
DEX Decrement
Index Register
X
IX – 1 ⇒ IX INH 09 — 3 — — — — — ∆——
DEY Decrement
Index Register
Y
IY – 1 ⇒ IY INH 18 09 — 4 — — — — — ∆——
EORA (opr) Exclusive OR A
with Memory
A ⊕ M ⇒ A A IMM
ADIR
AEXT
AIND,X
AIND,Y
88
98
B8
A8
18 A8
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆0—
EORB (opr) Exclusive OR B
with Memory
B ⊕ M ⇒ B B IMM
BDIR
BEXT
BIND,X
BIND,Y
C8
D8
F8
E8
18 E8
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆0—
FDIV Fractional
Divide 16 by 16
D / IX ⇒ IX; r ⇒ D INH 03 — 41 ————— ∆∆∆
IDIV Integer Divide
16 by 16
D / IX ⇒ IX; r ⇒ D INH 02 — 41 ————— ∆0∆
INC (opr) Increment
Memory Byte
M + 1 ⇒ MEXT
IND,X
IND,Y
7C
6C
18 6C
hh ll
ff
ff
6
6
7
———— ∆∆∆—
INCA Increment
Accumulator
A
A + 1 ⇒ A A INH 4C — 2 — — — — ∆∆∆—
Table 4-2. Instruction Set (Sheet 3 of 7)
Mnemonic Operation Description Addressing Instruction Condition Codes
Mode Opcode Operand Cycles S X H I N Z V C
Instruction Set
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 75
INCB Increment
Accumulator
B
B + 1 ⇒ B B INH 5C — 2 — — — — ∆∆∆—
INS Increment
Stack Pointer
SP + 1 ⇒ SP INH 31 — 3 ————————
INX Increment
Index Register
X
IX + 1 ⇒ IX INH 08 — 3 ————— ∆——
INY Increment
Index Register
Y
IY + 1 ⇒ IY INH 18 08 — 4 ————— ∆——
JMP (opr) Jump See Figure 3–2 EXT
IND,X
IND,Y
7E
6E
18 6E
hh ll
ff
ff
3
3
4
————————
JSR (opr) Jump to
Subroutine
See Figure 3–2 DIR
EXT
IND,X
IND,Y
9D
BD
AD
18 AD
dd
hh ll
ff
ff
5
6
6
7
————————
LDAA (opr) Load
Accumulator
A
M ⇒ A A IMM
A DIR
A EXT
A IND,X
A IND,Y
86
96
B6
A6
18 A6
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆0—
LDAB (opr) Load
Accumulator
B
M ⇒ B B IMM
B DIR
B EXT
B IND,X
B IND,Y
C6
D6
F6
E6
18 E6
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆0—
LDD (opr) Load Double
Accumulator
D
M ⇒ A,M + 1 ⇒ BIMM
DIR
EXT
IND,X
IND,Y
CC
DC
FC
EC
18 EC
jj kk
dd
hh ll
ff
ff
3
4
5
5
6
———— ∆∆0—
LDS (opr) Load Stack
Pointer
M : M + 1 ⇒ SP IMM
DIR
EXT
IND,X
IND,Y
8E
9E
BE
AE
18 AE
jj kk
dd
hh ll
ff
ff
3
4
5
5
6
———— ∆∆0—
LDX (opr) Load Index
Register
X
M : M + 1 ⇒ IX IMM
DIR
EXT
IND,X
IND,Y
CE
DE
FE
EE
CD EE
jj kk
dd
hh ll
ff
ff
3
4
5
5
6
———— ∆∆0—
LDY (opr) Load Index
Register
Y
M : M + 1 ⇒ IY IMM
DIR
EXT
IND,X
IND,Y
18 CE
18 DE
18 FE
1A EE
18 EE
jj kk
dd
hh ll
ff
ff
4
5
6
6
6
———— ∆∆0—
LSL (opr) Logical Shift
Left
EXT
IND,X
IND,Y
78
68
18 68
hh ll
ff
ff
6
6
7
———— ∆∆∆∆
LSLA Logical Shift
Left A
A INH 48 — 2 ———— ∆∆∆∆
LSLB Logical Shift
Left B
B INH 58 — 2 ———— ∆∆∆∆
LSLD Logical Shift
Left Double
INH 05 — 3 — — — — ∆∆∆∆
LSR (opr) Logical Shift
Right
EXT
IND,X
IND,Y
74
64
18 64
hh ll
ff
ff
6
6
7
———— 0 ∆∆∆
LSRA Logical Shift
Right A
A INH 44 — 2 ———— 0 ∆∆∆
LSRB Logical Shift
Right B
B INH 54 — 2 ———— 0 ∆∆∆
Table 4-2. Instruction Set (Sheet 4 of 7)
Mnemonic Operation Description Addressing Instruction Condition Codes
Mode Opcode Operand Cycles S X H I N Z V C
C
0
b7 b0
C0
b7 b0
C0
b7 b0
C
0
b7 b0
AB
b7
b0
C
0
b7 b0
C
0
b7 b0
C
0
b7 b0
Central Processor Unit (CPU)
M68HC11E Family Data Sheet, Rev. 5.1
76 Freescale Semiconductor
LSRD Logical Shift
Right Double
INH 04 — 3 — — — — 0 ∆∆∆
MUL Multiply 8 by 8 A ∗ B ⇒ D INH 3D — 10 ——————— ∆
NEG (opr) Two’s
Complement
Memory Byte
0 – M ⇒ MEXT
IND,X
IND,Y
70
60
18 60
hh ll
ff
ff
6
6
7
———— ∆∆∆∆
NEGA Two’s
Complement
A
0 – A ⇒ AAINH 40 — 2————∆∆∆∆
NEGB Two’s
Complement
B
0 – B ⇒ BBINH 50 — 2————∆∆∆∆
NOP No operation No Operation INH 01 — 2 — — — — — — — —
ORAA (opr) OR
Accumulator
A (Inclusive)
A + M ⇒ A A IMM
ADIR
AEXT
AIND,X
AIND,Y
8A
9A
BA
AA
18 AA
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆0—
ORAB (opr) OR
Accumulator
B (Inclusive)
B + M ⇒ B B IMM
BDIR
BEXT
BIND,X
BIND,Y
CA
DA
FA
EA
18 EA
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆0—
PSHA Push A onto
Stack
A ⇒ Stk,SP = SP – 1 A INH 36 — 3 — — — — — — — —
PSHB Push B onto
Stack
B ⇒ Stk,SP = SP – 1 B INH 37 — 3 — — — — — — — —
PSHX Push X onto
Stack (Lo
First)
IX ⇒ Stk,SP = SP – 2 INH 3C — 4 ————————
PSHY Push Y onto
Stack (Lo
First)
IY ⇒ Stk,SP = SP – 2 INH 18 3C — 5 ————————
PULA Pull A from
Stack
SP = SP + 1, A ⇐ StkA INH 32 — 4 ————————
PULB Pull B from
Stack
SP = SP + 1, B ⇐ StkB INH 33 — 4 ————————
PULX Pull X From
Stack (Hi
First)
SP = SP + 2, IX ⇐ Stk INH 38 — 5 ————————
PULY Pull Y from
Stack (Hi
First)
SP = SP + 2, IY ⇐ Stk INH 18 38 — 6 ————————
ROL (opr) Rotate Left EXT
IND,X
IND,Y
79
69
18 69
hh ll
ff
ff
6
6
7
———— ∆∆∆∆
ROLA Rotate Left A A INH 49 — 2 — — — — ∆∆∆∆
ROLB Rotate Left B B INH 59 — 2 — — — — ∆∆∆∆
ROR (opr) Rotate Right EXT
IND,X
IND,Y
76
66
18 66
hh ll
ff
ff
6
6
7
———— ∆∆∆∆
RORA Rotate Right A A INH 46 — 2 — — — — ∆∆∆∆
RORB Rotate Right B B INH 56 — 2 — — — — ∆∆∆∆
RTI Return from
Interrupt
See Figure 3–2 INH 3B — 12 ∆↓∆∆∆∆∆∆
RTS Return from
Subroutine
See Figure 3–2 INH 39 — 5 — — — — — — — —
SBA Subtract B from
A
A – B ⇒ A INH 10 — 2 ———— ∆∆∆∆
Table 4-2. Instruction Set (Sheet 5 of 7)
Mnemonic Operation Description Addressing Instruction Condition Codes
Mode Opcode Operand Cycles S X H I N Z V C
C
0
b7 b0AB
b7
b0
Cb7 b0
Cb7 b0
Cb7 b0
C
b7 b0
C
b7 b0
C
b7 b0
Instruction Set
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 77
SBCA (opr) Subtract with
Carry from A
A – M – C ⇒ AA IMM
ADIR
AEXT
AIND,X
AIND,Y
82
92
B2
A2
18 A2
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆∆∆
SBCB (opr) Subtract with
Carry from B
B – M – C ⇒ BB IMM
BDIR
BEXT
BIND,X
BIND,Y
C2
D2
F2
E2
18 E2
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆∆∆
SEC Set Carry 1 ⇒ C INH 0D — 2 ——————— 1
SEI Set Interrupt
Mask
1 ⇒ I INH 0F — 2 ——— 1 ————
SEV Set Overflow
Flag
1 ⇒ V INH 0B — 2 —————— 1 —
STAA (opr) Store
Accumulator
A
A ⇒ MADIR
AEXT
AIND,X
AIND,Y
97
B7
A7
18 A7
dd
hh ll
ff
ff
3
4
4
5
———— ∆∆0—
STAB (opr) Store
Accumulator
B
B ⇒ MBDIR
BEXT
BIND,X
BIND,Y
D7
F7
E7
18 E7
dd
hh ll
ff
ff
3
4
4
5
———— ∆∆0—
STD (opr) Store
Accumulator
D
A ⇒ M, B ⇒ M + 1 DIR
EXT
IND,X
IND,Y
DD
FD
ED
18 ED
dd
hh ll
ff
ff
4
5
5
6
———— ∆∆0—
STOP Stop Internal
Clocks
— INH CF — 2 ————————
STS (opr) Store Stack
Pointer
SP ⇒ M : M + 1 DIR
EXT
IND,X
IND,Y
9F
BF
AF
18 AF
dd
hh ll
ff
ff
4
5
5
6
———— ∆∆0—
STX (opr) Store Index
Register X
IX ⇒ M : M + 1 DIR
EXT
IND,X
IND,Y
DF
FF
EF
CD EF
dd
hh ll
ff
ff
4
5
5
6
———— ∆∆0—
STY (opr) Store Index
Register Y
IY ⇒ M : M + 1 DIR
EXT
IND,X
IND,Y
18 DF
18 FF
1A EF
18 EF
dd
hh ll
ff
ff
5
6
6
6
———— ∆∆0—
SUBA (opr) Subtract
Memory from
A
A – M ⇒ AAIMM
ADIR
AEXT
AIND,X
AIND,Y
80
90
B0
A0
18 A0
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆∆∆
SUBB (opr) Subtract
Memory from
B
B – M ⇒ BAIMM
ADIR
AEXT
AIND,X
AIND,Y
C0
D0
F0
E0
18 E0
ii
dd
hh ll
ff
ff
2
3
4
4
5
———— ∆∆∆∆
SUBD (opr) Subtract
Memory from
D
D – M : M + 1 ⇒ DIMM
DIR
EXT
IND,X
IND,Y
83
93
B3
A3
18 A3
jj kk
dd
hh ll
ff
ff
4
5
6
6
7
———— ∆∆∆∆
SWI Software
Interrupt
See Figure 3–2 INH 3F — 14 — — — 1 — — — —
TAB Transfer A to B A ⇒ B INH 16 — 2 ———— ∆∆0—
TAP Transfer A to
CC Register
A ⇒ CCR INH 06 — 2 ∆↓∆∆∆∆∆∆
TBA Transfer B to A B ⇒ A INH 17 — 2 ———— ∆∆0—
TEST TEST (Only in
Test Modes)
Address Bus Counts INH 00 — * — — — — — — — —
TPA Transfer CC
Register to A
CCR ⇒ A INH 07 — 2 ————————
TST (opr) Test for Zero or
Minus
M – 0 EXT
IND,X
IND,Y
7D
6D
18 6D
hh ll
ff
ff
6
6
7
———— ∆∆00
Table 4-2. Instruction Set (Sheet 6 of 7)
Mnemonic Operation Description Addressing Instruction Condition Codes
Mode Opcode Operand Cycles S X H I N Z V C
Central Processor Unit (CPU)
M68HC11E Family Data Sheet, Rev. 5.1
78 Freescale Semiconductor
TSTA Test A for Zero
or Minus
A – 0 A INH 4D — 2 — — — — ∆∆00
TSTB Test B for Zero
or Minus
B – 0 B INH 5D — 2 — — — — ∆∆00
TSX Transfer Stack
Pointer to X
SP + 1 ⇒ IX INH 30 — 3 ————————
TSY Transfer Stack
Pointer to Y
SP + 1 ⇒ IY INH 18 30 — 4 ————————
TXS Transfer X to
Stack Pointer
IX – 1 ⇒ SP INH 35 — 3 ————————
TYS Transfer Y to
Stack Pointer
IY – 1 ⇒ SP INH 18 35 — 4 ————————
WAI Wait for
Interrupt
Stack Regs & WAIT INH 3E — ** — — — — — — — —
XGDX Exchange D
with X
IX ⇒ D, D ⇒ IX INH 8F — 3 ————————
XGDY Exchange D
with Y
IY ⇒ D, D ⇒ IY INH 18 8F — 4 ————————
Cycle
* Infinity or until reset occurs
** 12 cycles are used beginning with the opcode fetch. A wait state is entered which remains in effect for an integer number of MPU E-clock
cycles (n) until an interrupt is recognized. Finally, two additional cycles are used to fetch the appropriate interrupt vector (14 + n total).
Operands
dd = 8-bit direct address ($0000–$00FF) (high byte assumed to be $00)
ff = 8-bit positive offset $00 (0) to $FF (255) (is added to index)
hh = High-order byte of 16-bit extended address
ii = One byte of immediate data
jj = High-order byte of 16-bit immediate data
kk = Low-order byte of 16-bit immediate data
ll = Low-order byte of 16-bit extended address
mm = 8-bit mask (set bits to be affected)
rr = Signed relative offset $80 (–128) to $7F (+127)
(offset relative to address following machine code offset byte))
Operators
( ) Contents of register shown inside parentheses
⇐Is transferred to
⇑Is pulled from stack
⇓Is pushed onto stack
• Boolean AND
+ Arithmetic addition symbol except where used as inclusive-OR symbol
in Boolean formula
⊕Exclusive-OR
∗Multiply
: Concatenation
– Arithmetic subtraction symbol or negation symbol (two’s complement)
Condition Codes
— Bit not changed
0 Bit always cleared
1 Bit always set
∆Bit cleared or set, depending on operation
↓Bit can be cleared, cannot become set
Table 4-2. Instruction Set (Sheet 7 of 7)
Mnemonic Operation Description Addressing Instruction Condition Codes
Mode Opcode Operand Cycles S X H I N Z V C
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 79
Chapter 5
Resets and Interrupts
5.1 Introduction
Resets and interrupt operations load the program counter with a vector that points to a new location from
which instructions are to be fetched. A reset immediately stops execution of the current instruction and
forces the program counter to a known starting address. Internal registers and control bits are initialized
so the MCU can resume executing instructions. An interrupt temporarily suspends normal program
execution while an interrupt service routine is being executed. After an interrupt has been serviced, the
main program resumes as if there had been no interruption.
5.2 Resets
The four possible sources of reset are:
• Power-on reset (POR)
• External reset (RESET)
• Computer operating properly (COP) reset
• Clock monitor reset
POR and RESET share the normal reset vector. COP reset and the clock monitor reset each has its own
vector.
5.2.1 Power-On Reset (POR)
A positive transition on VDD generates a power-on reset (POR), which is used only for power-up
conditions. POR cannot be used to detect drops in power supply voltages. A 4064 tCYC (internal clock
cycle) delay after the oscillator becomes active allows the clock generator to stabilize. If RESET is at
logical 0 at the end of 4064 tCYC, the CPU remains in the reset condition until RESET goes to logical 1.
The POR circuit only initializes internal circuitry during cold starts. Refer to
Figure 1-7. External Reset Circuit.
NOTE
It is important to protect the MCU during power transitions. Most M68HC11
systems need an external circuit that holds the RESET pin low whenever
VDD is below the minimum operating level. This external voltage level
detector, or other external reset circuits, are the usual source of reset in a
system.
Resets and Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
80 Freescale Semiconductor
5.2.2 External Reset (RESET)
The CPU distinguishes between internal and external reset conditions by sensing whether the reset pin
rises to a logic 1 in less than two E-clock cycles after an internal device releases reset. When a reset
condition is sensed, the RESET pin is driven low by an internal device for four E-clock cycles, then
released. Two E-clock cycles later it is sampled. If the pin is still held low, the CPU assumes that an
external reset has occurred. If the pin is high, it indicates that the reset was initiated internally by either
the COP system or the clock monitor.
CAUTION
Do not connect an external resistor capacitor (RC) power-up delay circuit to the reset pin of M68HC11
devices because the circuit charge time constant can cause the device to misinterpret the type of reset
that occurred.
5.2.3 Computer Operating Properly (COP) Reset
The MCU includes a COP system to help protect against software failures. When the COP is enabled, the
software is responsible for keeping a free-running watchdog timer from timing out. When the software is
no longer being executed in the intended sequence, a system reset is initiated.
The state of the NOCOP bit in the CONFIG register determines whether the COP system is enabled or
disabled. To change the enable status of the COP system, change the contents of the CONFIG register
and then perform a system reset. In the special test and bootstrap operating modes, the COP system is
initially inhibited by the disable resets (DISR) control bit in the TEST1 register. The DISR bit can
subsequently be written to 0 to enable COP resets.
The COP timer rate control bits CR[1:0] in the OPTION register determine the COP timeout period. The
system E clock is divided by 215 and then further scaled by a factor shown in Table 5-1. After reset, these
bits are 0, which selects the fastest timeout period. In normal operating modes, these bits can be written
only once within 64 bus cycles after reset.
Table 5-1. COP Timer Rate Select
CR[1:0] Divide
E/215 By
XTAL = 4.0 MHz
Timeout
– 0 ms, + 32.8 ms
XTAL = 8.0 MHz
Timeout
– 0 ms, + 16.4 ms
XTAL = 12.0 MHz
Timeout
– 0 ms, + 10.9 ms
XTAL = 16.0 MHz
Timeout
– 0 ms, + 8.2 ms
0 0 1 32.768 ms 16.384 ms 10.923 ms 8.19 ms
0 1 4 131.072 ms 65.536 ms 43.691 ms 32.8 ms
1 0 16 524.28 ms 262.14 ms 174.76 ms 131 ms
1 1 64 2.098 s 1.049 s 699.05 ms 524 ms
E = 1.0 MHz 2.0 MHz 3.0 MHz 4.0 MHz
Resets
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 81
Complete this 2-step reset sequence to service the COP timer:
1. Write $55 to COPRST to arm the COP timer clearing mechanism.
2. Write $AA to COPRST to clear the COP timer.
Performing instructions between these two steps is possible as long
as both steps are completed in the correct sequence before the timer times out.
5.2.4 Clock Monitor Reset
The clock monitor circuit is based on an internal resistor capacitor (RC) time delay. If no MCU clock edges
are detected within this RC time delay, the clock monitor can optionally generate a system reset. The
clock monitor function is enabled or disabled by the CME control bit in the OPTION register. The presence
of a timeout is determined by the RC delay, which allows the clock monitor to operate without any MCU
clocks.
Clock monitor is used as a backup for the COP system. Because the COP needs a clock to function, it is
disabled when the clock stops. Therefore, the clock monitor system can detect clock failures not detected
by the COP system.
Semiconductor wafer processing causes variations of the RC timeout values between individual devices.
An E-clock frequency below 10 kHz is detected as a clock monitor error. An E-clock frequency of 200 kHz
or more prevents clock monitor errors. Using the clock monitor function when the E-clock is below 200
kHz is not recommended.
Special considerations are needed when a STOP instruction is executed and the clock monitor is enabled.
Because the STOP function causes the clocks to be halted, the clock monitor function generates a reset
sequence if it is enabled at the time the stop mode was initiated. Before executing a STOP instruction,
clear the CME bit in the OPTION register to 0 to disable the clock monitor. After recovery from STOP, set
the CME bit to logic 1 to enable the clock monitor. Alternatively, executing a STOP instruction with the
CME bit set to logic 1 can be used as a software initiated reset.
Address $103A
Bit 7654321Bit 0
Read:
BIT 7 BIT 6 BIT 5 BIT 4 BIT 3 BIT 2 BIT 1 BIT 0
Write:
Reset: 0 0000000
Figure 5-1. Arm/Reset COP Timer Circuitry Register (COPRST)
Resets and Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
82 Freescale Semiconductor
5.2.5 System Configuration Options Register
ADPU — Analog-to-Digital Converter Power-Up Bit
Refer to Chapter 3 Analog-to-Digital (A/D) Converter.
CSEL — Clock Select Bit
Refer to Chapter 3 Analog-to-Digital (A/D) Converter.
IRQE — Configure IRQ for Edge-Sensitive-Only Operation Bit
0 = IRQ is configured for level-sensitive operation.
1 = IRQ is configured for edge-sensitive-only operation.
DLY — Enable Oscillator Startup Delay Bit
Refer to Chapter 2 Operating Modes and On-Chip Memory and Chapter 3 Analog-to-Digital (A/D)
Converter.
CME — Clock Monitor Enable Bit
This control bit can be read or written at any time and controls whether or not the internal clock monitor
circuit triggers a reset sequence when the system clock is slow or absent. When it is clear, the clock
monitor circuit is disabled, and when it is set, the clock monitor circuit is enabled. Reset clears the CME
bit.
0 = Clock monitor circuit disabled
1 = Slow or stopped clocks cause reset
Bit 2 — Unimplemented
Always reads 0
CR[1:0] — COP Timer Rate Select Bit
The internal E clock is first divided by 215 before it enters the COP watchdog system. These control
bits determine a scaling factor for the watchdog timer. See Table 5-1 for specific timeout settings.
Address: $1039
Bit 7654321Bit 0
Read:
ADPU CSEL IRQE(1) DLY(1) CME CR1(1) CR0(1)
Write:
Reset: 0 0010000
1. Can be written only once in first 64 cycles out of reset in normal mode or at any time in special modes
= Unimplemented
Figure 5-2. System Configuration Options Register (OPTION)
Effects of Reset
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 83
5.2.6 Configuration Control Register
EE[3:0] — EEPROM Mapping Bits
EE[3:0] apply only to MC68HC811E2. Refer to Chapter 2 Operating Modes and On-Chip Memory.
NOSEC — Security Mode Disable Bit
Refer to Chapter 2 Operating Modes and On-Chip Memory.
NOCOP — COP System Disable Bit
0 = COP enabled (forces reset on timeout)
1 = COP disabled (does not force reset on timeout)
ROMON — ROM (EPROM) Enable Bit
Refer to Chapter 2 Operating Modes and On-Chip Memory.
EEON — EEPROM Enable Bit
Refer to Chapter 2 Operating Modes and On-Chip Memory.
5.3 Effects of Reset
When a reset condition is recognized, the internal registers and control bits are forced to an initial state.
Depending on the cause of the reset and the operating mode, the reset vector can be fetched from any
of six possible locations. Refer to Table 5-2.
These initial states then control on-chip peripheral systems to force them to known startup states, as
described in the following subsections.
5.3.1 Central Processor Unit (CPU)
After reset, the central processor unit (CPU) fetches the restart vector from the appropriate address during
the first three cycles and begins executing instructions. The stack pointer and other CPU registers are
indeterminate immediately after reset; however, the X and I interrupt mask bits in the condition code
register (CCR) are set to mask any interrupt requests. Also, the S bit in the CCR is set to inhibit stop mode.
Address: $103F
Bit 7654321Bit 0
Read:
EE3 EE2 EE1 EE0 NOSEC NOCOP ROMON EEON
Write:
Reset: 0 0001111
Figure 5-3. Configuration Control Register (CONFIG)
Table 5-2. Reset Cause, Reset Vector, and Operating Mode
Cause of Reset Normal Mode
Vector
Special Test
or Bootstrap
POR or RESET pin $FFFE, FFFF $BFFE, $BFFF
Clock monitor failure $FFFC, FFFD $BFFC, $BFFD
COP Watchdog Timeout $FFFA, FFFB $BFFA, $BFFB
Resets and Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
84 Freescale Semiconductor
5.3.2 Memory Map
After reset, the INIT register is initialized to $01, mapping the RAM at $00 and the control registers at
$1000.
For the MC68HC811E2, the CONFIG register resets to $FF. EEPROM mapping bits (EE[3:0]) place the
EEPROM at $F800. Refer to the memory map diagram for MC68HC811E2 in Chapter 2 Operating Modes
and On-Chip Memory.
5.3.3 Timer
During reset, the timer system is initialized to a count of $0000. The prescaler bits are cleared, and all
output compare registers are initialized to $FFFF. All input capture registers are indeterminate after reset.
The output compare 1 mask (OC1M) register is cleared so that successful OC1 compares do not affect
any I/O pins. The other four output compares are configured so that they do not affect any I/O pins on
successful compares. All input capture edge-detector circuits are configured for capture disabled
operation. The timer overflow interrupt flag and all eight timer function interrupt flags are cleared. All nine
timer interrupts are disabled because their mask bits have been cleared.
The I4/O5 bit in the PACTL register is cleared to configure the I4/O5 function as OC5; however, the
OM5:OL5 control bits in the TCTL1 register are clear so OC5 does not control the PA3 pin.
5.3.4 Real-Time Interrupt (RTI)
The real-time interrupt flag (RTIF) is cleared and automatic hardware interrupts are masked. The rate
control bits are cleared after reset and can be initialized by software before the real-time interrupt (RTI)
system is used.
5.3.5 Pulse Accumulator
The pulse accumulator system is disabled at reset so that the pulse accumulator input (PAI) pin defaults
to being a general-purpose input pin.
5.3.6 Computer Operating Properly (COP)
The COP watchdog system is enabled if the NOCOP control bit in the CONFIG register is cleared and
disabled if NOCOP is set. The COP rate is set for the shortest duration timeout.
5.3.7 Serial Communications Interface (SCI)
The reset condition of the SCI system is independent of the operating mode. At reset, the SCI baud rate
control register (BAUD) is initialized to $04. All transmit and receive interrupts are masked and both the
transmitter and receiver are disabled so the port pins default to being general-purpose I/O lines. The SCI
frame format is initialized to an 8-bit character size. The send break and receiver wakeup functions are
disabled. The TDRE and TC status bits in the SCI status register (SCSR) are both 1s, indicating that there
is no transmit data in either the transmit data register or the transmit serial shift register. The RDRF, IDLE,
OR, NF, FE, PF, and RAF receive-related status bits in the SCI control register 2 (SCCR2) are cleared.
5.3.8 Serial Peripheral Interface (SPI)
The SPI system is disabled by reset. The port pins associated with this function default to being
general-purpose I/O lines.
Reset and Interrupt Priority
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 85
5.3.9 Analog-to-Digital (A/D) Converter
The analog-to-digital (A/D) converter configuration is indeterminate after reset. The ADPU bit is cleared
by reset, which disables the A/D system. The conversion complete flag is indeterminate.
5.3.10 System
The EEPROM programming controls are disabled, so the memory system is configured for normal read
operation. PSEL[3:0] are initialized with the value %0110, causing the external IRQ pin to have the
highest I-bit interrupt priority. The IRQ pin is configured for level-sensitive operation (for wired-OR
systems). The RBOOT, SMOD, and MDA bits in the HPRIO register reflect the status of the MODB and
MODA inputs at the rising edge of reset. MODA and MODB inputs select one of the four operating modes.
After reset, writing SMOD and MDA in special modes causes the MCU to change operating modes. Refer
to the description of HPRIO register in Chapter 2 Operating Modes and On-Chip Memory for a detailed
description of SMOD and MDA. The DLY control bit is set to specify that an oscillator startup delay is
imposed upon recovery from stop mode. The clock monitor system is disabled because CME is cleared.
5.4 Reset and Interrupt Priority
Resets and interrupts have a hardware priority that determines which reset or interrupt is serviced first
when simultaneous requests occur. Any maskable interrupt can be given priority over other maskable
interrupts.
The first six interrupt sources are not maskable. The priority arrangement for these sources is:
1. POR or RESET pin
2. Clock monitor reset
3. COP watchdog reset
4. XIRQ interrupt
5. Illegal opcode interrupt
6. Software interrupt (SWI)
The maskable interrupt sources have this priority arrangement:
1. IRQ
2. Real-time interrupt
3. Timer input capture 1
4. Timer input capture 2
5. Timer input capture 3
6. Timer output compare 1
7. Timer output compare 2
8. Timer output compare 3
9. Timer output compare 4
10. Timer input capture 4/output compare 5
11. Timer overflow
12. Pulse accumulator overflow
13. Pulse accumulator input edge
14. SPI transfer complete
15. SCI system (refer to Figure 5-7)
Resets and Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
86 Freescale Semiconductor
Any one of these interrupts can be assigned the highest maskable interrupt priority by writing the
appropriate value to the PSEL bits in the HPRIO register. Otherwise, the priority arrangement remains the
same. An interrupt that is assigned highest priority is still subject to global masking by the I bit in the CCR,
or by any associated local bits. Interrupt vectors are not affected by priority assignment. To avoid race
conditions, HPRIO can be written only while I-bit interrupts are inhibited.
5.4.1 Highest Priority Interrupt and Miscellaneous Register
RBOOT — Read Bootstrap ROM Bit
Has meaning only when the SMOD bit is a 1 (bootstrap mode or special test mode). At all other times
this bit is clear and cannot be written. Refer to Chapter 2 Operating Modes and On-Chip Memory for
more information.
SMOD — Special Mode Select Bit
This bit reflects the inverse of the MODB input pin at the rising edge of reset. Refer to Chapter 2
Operating Modes and On-Chip Memory for more information.
MDA — Mode Select A Bit
The mode select A bit reflects the status of the MODA input pin at the rising edge of reset. Refer to
Chapter 2 Operating Modes and On-Chip Memory for more information.
IRVNE — Internal Read Visibility/Not E Bit
The IRVNE control bit allows internal read accesses to be available on the external data bus during
operation in expanded modes. In single-chip and bootstrap modes, IRVNE determines whether the E
clock is driven out an external pin. For the MC68HC811E2, this bit is IRV and only controls internal
read visibility. Refer to Chapter 2 Operating Modes and On-Chip Memory for more information.
PSEL[3:0] — Priority Select Bits
These bits select one interrupt source to be elevated above all other I-bit-related sources and can be
written only while the I bit in the CCR is set (interrupts disabled).
Address: $103C
Bit 7654321Bit 0
Read:
RBOOT(1) SMOD(1) MDA(1) IRVNE PSEL2 PSEL2 PSEL1 PSEL0
Write:
Reset:
Single chip:00000110
Expanded:00100110
Bootstrap:11000110
Special test:01110110
1. The values of the RBOOT, SMOD, and MDA reset bits depend on the mode selected at the
RESET pin rising edge. Refer to Table 2-1. Hardware Mode Select Summary.
Figure 5-4. Highest Priority I-Bit Interrupt
and Miscellaneous Register (HPRIO)
Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 87
5.5 Interrupts
The MCU has 18 interrupt vectors that support 22 interrupt sources. The 15 maskable interrupts are
generated by on-chip peripheral systems. These interrupts are recognized when the global interrupt mask
bit (I) in the condition code register (CCR) is clear. The three non-maskable interrupt sources are illegal
opcode trap, software interrupt, and XIRQ pin. Refer to Table 5-4, which shows the interrupt sources and
vector assignments for each source.
For some interrupt sources, such as the SCI interrupts, the flags are automatically cleared during the
normal course of responding to the interrupt requests. For example, the RDRF flag in the SCI system is
cleared by the automatic clearing mechanism consisting of a read of the SCI status register while RDRF
is set, followed by a read of the SCI data register. The normal response to an RDRF interrupt request
would be to read the SCI status register to check for receive errors, then to read the received data from
the SCI data register. These steps satisfy the automatic clearing mechanism without requiring special
instructions.
Table 5-3. Highest Priority Interrupt Selection
PSEL[3:0] Interrupt Source Promoted
0 0 0 0 Timer overflow
0 0 0 1 Pulse accumulator overflow
0 0 1 0 Pulse accumulator input edge
0 0 1 1 SPI serial transfer complete
0 1 0 0 SCI serial system
0 1 0 1 Reserved (default to IRQ)
0 1 1 0 IRQ (external pin or parallel I/O)
0 1 1 1 Real-time interrupt
1 0 0 0 Timer input capture 1
1 0 0 1 Timer input capture 2
1 0 1 0 Timer input capture 3
1 0 1 1 Timer output compare 1
1 1 0 0 Timer output compare 2
1 1 0 1 Timer output compare 3
1 1 1 0 Timer output compare 4
1 1 1 1 Timer input capture 4/output compare 5
Resets and Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
88 Freescale Semiconductor
5.5.1 Interrupt Recognition and Register Stacking
An interrupt can be recognized at any time after it is enabled by its local mask, if any, and by the global
mask bit in the CCR. Once an interrupt source is recognized, the CPU responds at the completion of the
instruction being executed. Interrupt latency varies according to the number of cycles required to
complete the current instruction. When the CPU begins to service an interrupt, the contents of the CPU
registers are pushed onto the stack in the order shown in Table 5-5. After the CCR value is stacked, the
I bit and the X bit, if XIRQ is pending, are set to inhibit further interrupts. The interrupt vector for the highest
priority pending source is fetched and execution continues at the address specified by the vector. At the
Table 5-4. Interrupt and Reset Vector Assignments
Vector Address Interrupt Source CCR
Mask Bit
Local
Mask
FFC0, C1 – FFD4, D5 Reserved — —
FFD6, D7
SCI serial system
• SCI receive data register full
• SCI receiver overrun
• SCI transmit data register empty
• SCI transmit complete
• SCI idle line detect
I
RIE
RIE
TIE
TCIE
ILIE
FFD8, D9 SPI serial transfer complete I SPIE
FFDA, DB Pulse accumulator input edge I PAII
FFDC, DD Pulse accumulator overflow I PAOVI
FFDE, DF Timer overflow I TOI
FFE0, E1 Timer input capture 4/output compare 5 I I4/O5I
FFE2, E3 Timer output compare 4 I OC4I
FFE4, E5 Timer output compare 3 I OC3I
FFE6, E7 Timer output compare 2 I OC2I
FFE8, E9 Timer output compare 1 I OC1I
FFEA, EB Timer input capture 3 I IC3I
FFEC, ED Timer input capture 2 I IC2I
FFEE, EF Timer input capture 1 I IC1I
FFF0, F1 Real-time interrupt I RTII
FFF2, F3 IRQ (external pin) I None
FFF4, F5 XIRQ pin X None
FFF6, F7 Software interrupt None None
FFF8, F9 Illegal opcode trap None None
FFFA, FB COP failure None NOCOP
FFFC, FD Clock monitor fail None CME
FFFE, FF RESET None None
Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 89
end of the interrupt service routine, the return-from-interrupt instruction is executed and the saved
registers are pulled from the stack in reverse order so that normal program execution can resume. Refer
to Chapter 4 Central Processor Unit (CPU).
5.5.2 Non-Maskable Interrupt Request (XIRQ)
Non-maskable interrupts are useful because they can always interrupt CPU operations. The most
common use for such an interrupt is for serious system problems, such as program runaway or power
failure. The XIRQ input is an updated version of the NMI (non-maskable interrupt) input of earlier MCUs.
Upon reset, both the X bit and I bit of the CCR are set to inhibit all maskable interrupts and XIRQ. After
minimum system initialization, software can clear the X bit by a TAP instruction, enabling XIRQ interrupts.
Thereafter, software cannot set the X bit. Thus, an XIRQ interrupt is a non-maskable interrupt. Because
the operation of the I-bit-related interrupt structure has no effect on the X bit, the internal XIRQ pin remains
unmasked. In the interrupt priority logic, the XIRQ interrupt has a higher priority than any source that is
maskable by the I bit. All I-bit-related interrupts operate normally with their own priority relationship.
When an I-bit-related interrupt occurs, the I bit is automatically set by hardware after stacking the CCR
byte. The X bit is not affected. When an X-bit-related interrupt occurs, both the X and I bits are
automatically set by hardware after stacking the CCR. A return-from-interrupt instruction restores the X
and I bits to their pre-interrupt request state.
5.5.3 Illegal Opcode Trap
Because not all possible opcodes or opcode sequences are defined, the MCU includes an illegal opcode
detection circuit, which generates an interrupt request. When an illegal opcode is detected and the
interrupt is recognized, the current value of the program counter is stacked. After interrupt service is
complete, reinitialize the stack pointer so repeated execution of illegal opcodes does not cause stack
underflow. Left uninitialized, the illegal opcode vector can point to a memory location that contains an
illegal opcode. This condition causes an infinite loop that causes stack underflow. The stack grows until
the system crashes.
The illegal opcode trap mechanism works for all unimplemented opcodes on all four opcode map pages.
The address stacked as the return address for the illegal opcode interrupt is the address of the first byte
of the illegal opcode. Otherwise, it would be almost impossible to determine whether the illegal opcode
had been one or two bytes. The stacked return address can be used as a pointer to the illegal opcode so
the illegal opcode service routine can evaluate the offending opcode.
Table 5-5. Stacking Order on Entry to Interrupts
Memory Location CPU Registers
SP PCL
SP–1 PCH
SP–2 IYL
SP–3 IYH
SP–4 IXL
SP–5 IXH
SP–6 ACCA
SP–7 ACCB
SP–8 CCR
Resets and Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
90 Freescale Semiconductor
5.5.4 Software Interrupt (SWI)
SWI is an instruction, and thus cannot be interrupted until complete. SWI is not inhibited by the global
mask bits in the CCR. Because execution of SWI sets the I mask bit, once an SWI interrupt begins, other
interrupts are inhibited until SWI is complete, or until user software clears the I bit in the CCR.
5.5.5 Maskable Interrupts
The maskable interrupt structure of the MCU can be extended to include additional external interrupt
sources through the IRQ pin. The default configuration of this pin is a low-level sensitive wired-OR
network. When an event triggers an interrupt, a software accessible interrupt flag is set. When enabled,
this flag causes a constant request for interrupt service. After the flag is cleared, the service request is
released.
5.5.6 Reset and Interrupt Processing
Figure 5-5 and Figure 5-6 illustrate the reset and interrupt process. Figure 5-5 illustrates how the CPU
begins from a reset and how interrupt detection relates to normal opcode fetches. Figure 5-6 is an
expansion of a block in Figure 5-5 and illustrates interrupt priorities. Figure 5-7 shows the resolution of
interrupt sources within the SCI subsystem.
5.6 Low-Power Operation
Both stop mode and wait mode suspend CPU operation until a reset or interrupt occurs. Wait mode
suspends processing and reduces power consumption to an intermediate level. Stop mode turns off all
on-chip clocks and reduces power consumption to an absolute minimum while retaining the contents of
the entire RAM array.
5.6.1 Wait Mode
The WAI opcode places the MCU in wait mode, during which the CPU registers are stacked and CPU
processing is suspended until a qualified interrupt is detected. The interrupt can be an external IRQ, an
XIRQ, or any of the internally generated interrupts, such as the timer or serial interrupts. The on-chip
crystal oscillator remains active throughout the wait standby period.
The reduction of power in the wait condition depends on how many internal clock signals driving on-chip
peripheral functions can be shut down. The CPU is always shut down during wait. While in the wait state,
the address/data bus repeatedly runs read cycles to the address where the CCR contents were stacked.
The MCU leaves the wait state when it senses any interrupt that has not been masked.
The free-running timer system is shut down only if the I bit is set to 1 and the COP system is disabled by
NOCOP being set to 1. Several other systems also can be in a reduced power-consumption state
depending on the state of software-controlled configuration control bits. Power consumption by the
analog-to-digital (A/D) converter is not affected significantly by the wait condition. However, the A/D
converter current can be eliminated by writing the ADPU bit to 0. The SPI system is enabled or disabled
by the SPE control bit. The SCI transmitter is enabled or disabled by the TE bit, and the SCI receiver is
enabled or disabled by the RE bit. Therefore, the power consumption in wait is dependent on the
particular application.
Low-Power Operation
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 91
Figure 5-5. Processing Flow Out of Reset (Sheet 1 of 2)
2A
BIT X IN
Y
N
XIRQ Y
N
PIN LOW?
CCR = 1?
BEGIN INSTRUCTION
SEQUENCE
1A
STACK CPU
REGISTERS
SET BITS I AND X
FETCH VECTOR
$FFF4, $FFF5
SET BITS S, I, AND X
RESET MCU
HARDWARE
POWER-ON RESET
(POR)
EXTERNAL RESET
CLOCK MONITOR FAIL
(WITH CME = 1)
COP WATCHDOG
TIMEOUT
(WITH NOCOP = 0)
DELAY 4064 E CYCLES
LOAD PROGRAM COUNTER
WITH CONTENTS OF
$FFFE, $FFFF
(VECTOR FETCH)
LOAD PROGRAM COUNTER
WITH CONTENTS OF
$FFFC, $FFFD
(VECTOR FETCH)
LOAD PROGRAM COUNTER
WITH CONTENTS OF
$FFFA, $FFFB
(VECTOR FETCH)
HIGHEST
PRIORITY
LOWEST
PRIORITY
Resets and Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
92 Freescale Semiconductor
Figure 5-5. Processing Flow Out of Reset (Sheet 2 of 2)
BIT I IN
CCR = 1?
2A
Y
N
ANY I-BIT
INTERRUPT Y
N
PENDING?
FETCH OPCODE
ILLEGAL
OPCODE?
Y
N
WAI Y
N
INSTRUCTION?
SWI
INSTRUCTION?
Y
N
RTI
INSTRUCTION?
Y
N
EXECUTE THIS
INSTRUCTION
STACK CPU
REGISTERS
ANY
N
Y
INTERRUPT
PENDING?
SET BIT I IN CCR
RESOLVE INTERRUPT
PRIORITY AND FETCH
VECTOR FOR HIGHEST
PENDING SOURCE
STACK CPU
REGISTERS
SET BIT I IN CCR
FETCH VECTOR
$FFF8, $FFF9
STACK CPU
REGISTERS
SET BIT I IN CCR
FETCH VECTOR
$FFF6, $FFF7
RESTORE CPU
REGISTERS
FROM STACK
1A
STACK CPU
REGISTERS
SEE FIGURE 5–2
Low-Power Operation
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 93
Figure 5-6. Interrupt Priority Resolution (Sheet 1 of 2)
2A
BEGIN
SET X BIT IN CCR
FETCH VECTOR
$FFF4, FFF5
X BIT
IN CCR
SET ?
YES
NO
XIRQ PIN
LOW ?
YES
NO
HIGHEST
PRIORITY
INTERRUPT
?
YES
NO
IRQ ? YES
NO
FETCH VECTOR
$FFF2, FFF3
FETCH VECTOR
$FFF0, FFF1
RTII = 1 ? YES
NO
REAL-TIME
INTERRUPT
?
YES
NO
FETCH VECTOR
$FFEE, FFEF
IC1I = 1 ?
YES
NO
TIMER
IC1F ?
YES
NO
FETCH VECTOR
$FFEC, FFED
IC2I = 1 ?
YES
NO
TIMER
IC2F ?
YES
NO
FETCH VECTOR
$FFEA, FFEB
IC3I = 1 ?
YES
NO
TIMER
IC3F ?
YES
NO
FETCH VECTOR
$FFE8, FFE9
OC1I = 1 ?
YES
NO
TIMER
OC1F ?
YES
NO
2B
FETCH VECTOR
Resets and Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
94 Freescale Semiconductor
Figure 5-6. Interrupt Priority Resolution (Sheet 2 of 2)
TOI = 1?
Y
N
Y
N
PAOVI = 1?
PAII = 1?
Y
N
SPIE = 1?
Y
N
Y
N
FLAG Y
N
Y
N
FLAG
FLAG Y
N
FLAGS Y
N
PAIF = 1?
SPIF = 1? OR
TOF = 1?
PAOVF = 1
FETCH VECTOR
$FFDE, $FFDF
FETCH VECTOR
$FFDC, $FFDD
FETCH VECTOR
$FFDA, $FFDB
FETCH VECTOR
$FFD6, $FFD7
FETCH VECTOR
$FFD8, $FFD9
OC2I = 1?
Y
N
Y
N
OC3I = 1?
OC4I = 1?
Y
N
I4/O5I = 1?
Y
N
FLAG Y
N
Y
N
FLAG
FLAG Y
N
FLAG Y
N
OC4F = 1?
I4/O5IF = 1?
OC2F = 1?
OC3F = 1
FETCH VECTOR
$FFE6, $FFE7
FETCH VECTOR
$FFE4, $FFE5
FETCH VECTOR
$FFE2, $FFE3
FETCH VECTOR
$FFE0, $FFE1
MODF = 1?
INTERRUPT?
SEE FIGURE
5–3
2A 2B
END
FETCH VECTOR
$FFF2, $FFF3
SCI
Low-Power Operation
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 95
Figure 5-7. Interrupt Source Resolution Within SCI
5.6.2 Stop Mode
Executing the STOP instruction while the S bit in the CCR is equal to 0 places the MCU in stop mode. If
the S bit is not 0, the stop opcode is treated as a no-op (NOP). Stop mode offers minimum power
consumption because all clocks, including the crystal oscillator, are stopped while in this mode. To exit
stop and resume normal processing, a logic low level must be applied to one of the external interrupts
(IRQ or XIRQ) or to the RESET pin. A pending edge-triggered IRQ can also bring the CPU out of stop.
Because all clocks are stopped in this mode, all internal peripheral functions also stop. The data in the
internal RAM is retained as long as VDD power is maintained. The CPU state and I/O pin levels are static
and are unchanged by stop. Therefore, when an interrupt comes to restart the system, the MCU resumes
processing as if there were no interruption. If reset is used to restart the system, a normal reset sequence
results in which all I/O pins and functions are also restored to their initial states.
To use the IRQ pin as a means of recovering from stop, the I bit in the CCR must be clear (IRQ not
masked). The XIRQ pin can be used to wake up the MCU from stop regardless of the state of the X bit in
the CCR, although the recovery sequence depends on the state of the X bit. If X is set to 0 (XIRQ not
FLAG Y
N
OR = 1? Y
N
Y
N
TDRE = 1?
TC = 1?
Y
N
IDLE = 1?
Y
N
Y
N
Y
N
Y
N
ILIE = 1?
RIE = 1?
TIE = 1?
BEGIN
RE = 1? Y
N
Y
N
TE = 1?
TCIE = 1?
Y
N
RE = 1?
Y
N
RDRF = 1?
VALID SCI REQUEST
NO
VALID SCI REQUEST
Resets and Interrupts
M68HC11E Family Data Sheet, Rev. 5.1
96 Freescale Semiconductor
masked), the MCU starts up, beginning with the stacking sequence leading to normal service of the XIRQ
request. If X is set to 1 (XIRQ masked or inhibited), then processing continues with the instruction that
immediately follows the STOP instruction, and no XIRQ interrupt service is requested or pending.
Because the oscillator is stopped in stop mode, a restart delay may be imposed to allow oscillator
stabilization upon leaving stop. If the internal oscillator is being used, this delay is required; however, if a
stable external oscillator is being used, the DLY control bit can be used to bypass this startup delay. The
DLY control bit is set by reset and can be optionally cleared during initialization. If the DLY equal to 0
option is used to avoid startup delay on recovery from stop, then reset should not be used as the means
of recovering from stop, as this causes DLY to be set again by reset, imposing the restart delay. This same
delay also applies to power-on reset, regardless of the state of the DLY control bit, but does not apply to
a reset while the clocks are running.
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 97
Chapter 6
Parallel Input/Output (I/O) Ports
6.1 Introduction
All M68HC11 E-series MCUs have five input/output (I/O) ports and up to 38 I/O lines, depending on the
operating mode. Refer to Table 6-1 for a summary of the ports and their shared functions.
Port pin function is mode dependent. Do not confuse pin function with the electrical state of the pin at
reset. Port pins are either driven to a specified logic level or are configured as high-impedance inputs. I/O
pins configured as high-impedance inputs have port data that is indeterminate.
In port descriptions, an I indicates this condition. Port pins that are driven to a known logic level during
reset are shown with a value of either 1 or 0. Some control bits are unaffected by reset. Reset states for
these bits are indicated with a U.
Table 6-1. Input/Output Ports
Port Input
Pins
Output
Pins
Bidirectional
Pins Shared Functions
Port A 3 3 2 Timer
Port B — 8 — High-order address
Port C — — 8 Low-order address and data bus
Port D — — 6 Serial communications interface (SCI)
and serial peripheral interface (SPI)
Port E 8 — — Analog-to-digital (A/D) converter
Parallel Input/Output (I/O) Ports
M68HC11E Family Data Sheet, Rev. 5.1
98 Freescale Semiconductor
6.2 Port A
Port A shares functions with the timer system and has:
• Three input-only pins
• Three output-only pins
• Two bidirectional I/O pins
DDRA7 — Data Direction for Port A Bit 7
Overridden if an output compare function is configured to control the PA7 pin
0 = Input
1 = Output
The pulse accumulator uses port A bit 7 as the PAI input, but the pin can also be used as
general-purpose I/O or as an output compare.
NOTE
Even when port A bit 7 is configured as an output, the pin still drives the
input to the pulse accumulator.
PAEN — Pulse Accumulator System Enable Bit
Refer to Chapter 9 Timing Systems.
PAMOD — Pulse Accumulator Mode Bit
Refer to Chapter 9 Timing Systems.
PEDGE — Pulse Accumulator Edge Control Bit
Refer to Chapter 9 Timing Systems.
DDRA3 — Data Direction for Port A Bit 3
This bit is overridden if an output compare function is configured to control the PA3 pin.
0 = Input
1 = Output
I4/O5 — Input Capture 4/Output Compare 5 Bit
Refer to Chapter 9 Timing Systems.
RTR[1:0] — RTI Interrupt Rate Select Bits
Refer to Chapter 9 Timing Systems.
Address: $1000
Bit 7654321Bit 0
Read: PA7 PA6 PA5 PA4 PA3 PA2 PA1 PA0
Write:
Reset:I000IIII
Alternate function: PAI OC2 OC3 OC4 IC4/OC5 IC1 IC2 IC3
And/or: OC1 OC1 OC1 OC1 OC1 — — —
I = Indeterminate after reset
Figure 6-1. Port A Data Register (PORTA)
Address: $1026
Bit 7654321Bit 0
Read: DDRA7 PAEWN PAMOD PEDGE DDRA3 I4/O5 RTR1 RTR0
Write:
Reset:00000000
Figure 6-2. Pulse Accumulator Control Register (PACTL)
Port B
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 99
6.3 Port B
In single-chip or bootstrap modes, port B pins are general-purpose outputs. In expanded or special test
modes, port B pins are high-order address outputs.
6.4 Port C
In single-chip and bootstrap modes, port C pins reset to high-impedance inputs. (DDRC bits are set to 0.)
In expanded and special test modes, port C pins are multiplexed address/data bus and the port C register
address is treated as an external memory location.
Address: $1004
Bit 7654321Bit 0
Single-chip or bootstrap modes:
Read:
PB7 PB6 PB5 PB4 PB3 PB2 PB1 PB0
Write:
Reset:00000000
Expanded or special test modes:
Read:
ADDR15 ADDR14 ADDR13 ADDR12 ADDR11 ADDR10 ADDR9 ADDR8
Write:
Reset:00000000
Figure 6-3. Port B Data Register (PORTB)
Address: $1003
Bit 7654321Bit 0
Single-chip or bootstrap modes:
Read:
PC7 PC6 PC5 PC4 PC3 PC2 PC1 PC0
Write:
Reset: Indeterminate after reset
Expanded or special test modes:
Read: ADDR7
DATA7
ADDR6
DATA6
ADDR5
DATA5
ADDR4
DATA4
ADDR3
DATA3
ADDR2
DATA2
ADDR1
DATA1
ADDR0
DATA0
Write:
Reset: Indeterminate after reset
Figure 6-4. Port C Data Register (PORTC)
Address: $1005
Bit 7654321Bit 0
Read:
PCL7 PCL6 PCL5 PCL4 PCL3 PCL2 PCL1 PCL0
Write:
Reset: Indeterminate after reset
Figure 6-5. Port C Latched Register (PORTCL)
Parallel Input/Output (I/O) Ports
M68HC11E Family Data Sheet, Rev. 5.1
100 Freescale Semiconductor
PORTCL is used in the handshake clearing mechanism. When an active edge occurs on the STRA pin,
port C data is latched into the PORTCL register. Reads of this register return the last value latched into
PORTCL and clear STAF flag (following a read of PIOC with STAF set).
DDRC[7:0] — Port C Data Direction Bits
In the 3-state variation of output handshake mode, clear the corresponding DDRC bits. Refer to Figure
10-13. 3-State Variation of Output Handshake Timing Diagram (STRA Enables Output Buffer).
0 = Input
1 = Output
6.5 Port D
In all modes, port D bits [5:0] can be used either for general-purpose I/O or with the serial communications
interface (SCI) and serial peripheral interface (SPI) subsystems. During reset, port D pins PD[5:0] are
configured as high-impedance inputs (DDRD bits cleared).
Bits [7:6] — Unimplemented
Always read 0
DDRD[5:0] — Port D Data Direction Bits
When DDRD bit 5 is 1 and MSTR = 1 in SPCR, PD5/SS is a general-purpose output and mode fault
logic is disabled.
0 = Input
1 = Output
Address: $1007
Bit 7654321Bit 0
Read: DDRC7 DDRC6 DDRC5 DDRC4 DDRC3 DDRC2 DDRC1 DDRC0
Write:
Reset:00000000
Figure 6-6. Port C Data Direction Register (DDRC)
Address: $1008
Bit 7654321Bit 0
Read: 0 0 PD5 PD4 PD3 PD2 PD1 PD0
Write:
Reset:——IIIIII
Alternate Function: — — PD5
SS
PD4
SCK
PD3
MOSI
PD2
MISO
PD1
Tx
PD0
RxD
I = Indeterminate after reset
Figure 6-7. Port D Data Register (PORTD)
Address: $1009
Bit 7654321Bit 0
Read: DDRD5 DDRD4 DDRD3 DDRD2 DDRD1 DDRD0
Write:
Reset:00000000
= Unimplemented
Figure 6-8. Port D Data Direction Register (DDRD)
Port E
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 101
6.6 Port E
Port E is used for general-purpose static inputs or pins that share functions with the analog-to-digital (A/D)
converter system. When some port E pins are being used for general-purpose input and others are being
used as A/D inputs, PORTE should not be read during the sample portion of an A/D conversion.
6.7 Handshake Protocol
Simple and full handshake input and output functions are available on ports B and C pins in single-chip
mode. In simple strobed mode, port B is a strobed output port and port C is a latching input port. The two
activities are available simultaneously.
The STRB output is pulsed for two E-clock periods each time there is a write to the PORTB register. The
INVB bit in the PIOC register controls the polarity of STRB pulses. Port C levels are latched into the
alternate port C latch (PORTCL) register on each assertion of the STRA input. STRA edge select, flag,
and interrupt enable bits are located in the PIOC register. Any or all of the port C lines can still be used
as general-purpose I/O while in strobed input mode.
Full handshake modes use port C pins and the STRA and STRB lines. Input and output handshake
modes are supported, and output handshake mode has a 3-stated variation. STRA is an edge-detecting
input and STRB is a handshake output. Control and enable bits are located in the PIOC register.
In full input handshake mode, the MCU asserts STRB to signal an external system that it is ready to latch
data. Port C logic levels are latched into PORTCL when the STRA line is asserted by the external system.
The MCU then negates STRB. The MCU reasserts STRB after the PORTCL register is read. In this mode,
a mix of latched inputs, static inputs, and static outputs is allowed on port C, differentiated by the data
direction bits and use of the PORTC and PORTCL registers.
In full output handshake mode, the MCU writes data to PORTCL which, in turn, asserts the STRB output
to indicate that data is ready. The external system reads port C data and asserts the STRA input to
acknowledge that data has been received.
In the 3-state variation of output handshake mode, lines intended as 3-state handshake outputs are
configured as inputs by clearing the corresponding DDRC bits. The MCU writes data to PORTCL and
asserts STRB. The external system responds by activating the STRA input, which forces the MCU to drive
the data in PORTC out on all of the port C lines. After the trailing edge of the active signal on STRA, the
MCU negates the STRB signal. The 3-state mode variation does not allow part of port C to be used for
static inputs while other port C pins are being used for handshake outputs. Refer to the 6.8 Parallel I/O
Control Register for further information.
Address: $100A
Bit 7654321Bit 0
Read:
PE7 PE6 PE5 PE4 PE3 PE2 PE1 PE0
Write:
Reset: Indeterminate after reset
Alternate Function: AN7 AN6 AN5 AN4 AN3 AN2 AN1 AN0
Figure 6-9. Port E Data Register (PORTE)
Parallel Input/Output (I/O) Ports
M68HC11E Family Data Sheet, Rev. 5.1
102 Freescale Semiconductor
6.8 Parallel I/O Control Register
The parallel handshake functions are available only in the single-chip operating mode. PIOC is a
read/write register except for bit 7, which is read only. Table 6-2 shows a summary of handshake
operations.
STAF — Strobe A Interrupt Status Flag
STAF is set when the selected edge occurs on strobe A. This bit can be cleared by a read of PIOC with
STAF set followed by a read of PORTCL (simple strobed or full input handshake mode) or a write to
PORTCL (output handshake mode).
0 = No edge on strobe A
1 = Selected edge on strobe A
STAI — Strobe A Interrupt Enable Mask Bit
0 = STAF does not request interrupt
1 = STAF requests interrupt
Table 6-2. Parallel I/O Control
STAF
Clearing
Sequence
HNDS OIN PLS EGA Port B Port C
Simple
strobed
mode
Read
PIOC with
STAF = 1
then read
PORTCL
0X X
Inputs latched into
PORTCL on any
active edge on
STRA
STRB pulses
on writes
to PORTB
Full-input
hand-
shake
mode
Read
PIOC with
STAF = 1
then read
PORTCL
10
0 = STRB
active level
1 = STRB
active pulse
Inputs latched into
PORTCL on any
active edge on
STRA
Normal output
port, unaffected
in handshake
modes
Full-
output
hand-
shake
mode
Read
PIOC with
STAF = 1
then write
PORTCL
11
0 = STRB
active level
1 = STRB
active pulse
Driven as outputs if
STRA at active
level; follows
DDRC
if STRA not at
active level
Normal output
port, unaffected
in handshake
modes
Address: $1002
Bit 7654321Bit 0
Read:
STAF STAI CWOM HNDS OIN PLS EGA INVB
Write:
Reset:00000U11
U = Unaffected
Figure 6-10. Parallel I/O Control Register (PIOC)
1
0
0
1
0
1
Port C
Driven
STRA
Active Edge
Follow
DDRC
Follow
DDRC
Parallel I/O Control Register
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 103
CWOM — Port C Wired-OR Mode Bit (affects all eight port C pins)
It is customary to have an external pullup resistor on lines that are driven by open-drain devices.
0 = Port C outputs are normal CMOS outputs.
1 = Port C outputs are open-drain outputs.
HNDS — Handshake Mode Bit
0 = Simple strobe mode
1 = Full input or output handshake mode
OIN — Output or Input Handshake Select Bit
HNDS must be set to 1 for this bit to have meaning.
0 = Input handshake
1 = Output handshake
PLS — Pulsed/Interlocked Handshake Operation Bit
HNDS must be set to 1 for this bit to have meaning. When interlocked handshake is selected, strobe
B is active until the selected edge of strobe A is detected.
0 = Interlocked handshake
1 = Pulsed handshake (Strobe B pulses high for two E-clock cycles.)
EGA — Active Edge for Strobe A Bit
0 = STRA falling edge selected, high level activates port C outputs (output handshake)
1 = STRA rising edge selected, low level activates port C outputs (output handshake)
INVB — Invert Strobe B Bit
0 = Active level is logic 0.
1 = Active level is logic 1.
Parallel Input/Output (I/O) Ports
M68HC11E Family Data Sheet, Rev. 5.1
104 Freescale Semiconductor
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 105
Chapter 7
Serial Communications Interface (SCI)
7.1 Introduction
The serial communications interface (SCI) is a universal asynchronous receiver transmitter (UART), one
of two independent serial input/output (I/O) subsystems in the M68HC11 E series of microcontrollers. It
has a standard non-return-to-zero (NRZ) format (one start bit , eight or nine data bits, and one stop bit).
Several baud rates are available. The SCI transmitter and receiver are independent, but use the same
data format and bit rate.
All members of the E series contain the same SCI, with one exception. The SCI system in the
MC68HC11E20 and MC68HC711E20 MCUs have an enhanced SCI baud rate generator. A divide-by-39
stage has been added that is enabled by an extra bit in the BAUD register. This increases the available
SCI baud rate selections. Refer to Figure 7-8 and 7.7.5 Baud Rate Register.
7.2 Data Format
The serial data format requires these conditions:
1. An idle line in the high state before transmission or reception of a message
2. A start bit, logic 0, transmitted or received, that indicates the start of each character
3. Data that is transmitted and received least significant bit (LSB) first
4. A stop bit, logic 1, used to indicate the end of a frame. A frame consists of a start bit, a character
of eight or nine data bits, and a stop bit.
5. A break, defined as the transmission or reception of a logic 0 for some multiple number of frames
Selection of the word length is controlled by the M bit of SCI control register (SCCR1).
7.3 Transmit Operation
The SCI transmitter includes a parallel transmit data register (SCDR) and a serial shift register. The
contents of the serial shift register can be written only through the SCDR. This double buffered operation
allows a character to be shifted out serially while another character is waiting in the SCDR to be
transferred into the
serial shift register. The output of the serial shift register is applied to TxD as long as transmission is in
progress or the transmit enable (TE) bit of serial communication control register 2 (SCCR2) is set. The
block diagram, Figure 7-1, shows the transmit serial shift register and the buffer logic at the top of the
figure.
Serial Communications Interface (SCI)
M68HC11E Family Data Sheet, Rev. 5.1
106 Freescale Semiconductor
Figure 7-1. SCI Transmitter Block Diagram
FE
NF
OR
IDLE
RDRF
TC
TDRE
SCSR
INTERRUPT STATUS
SBK
RWU
RE
TE
ILIE
RIE
TCIE
TIE
SCCR2
SCI CONTROL 2
TRANSMITTER
CONTROL LOGIC
TCIE
TC
TIE
TDRE
SCI Rx
REQUESTS
SCI INTERRUPT
REQUEST
INTERNAL
DATA BUS
PIN BUFFER
AND CONTROL
H(8)76543210L
10 (11) - BIT Tx SHIFT REGISTER
DDD1
PD1
TxD
SCDR
Tx BUFFER
TRANSFER Tx BUFFER
SHIFT ENABLE
JAM ENABLE
PREAMBLE—JAM 1s
BREAK—JAM 0s
WRITE ONLY
FORCE PIN
DIRECTION (OUT)
SIZE 8/9
WAKE
M
T8
R8
SCCR1
SCI CONTROL 1
TRANSMITTER
BAUD RATE
CLOCK
8
8
8
SEE NOTE
Note: Refer to Figure B-1. EVBU Schematic Diagram for an example of connecting TxD to a PC.
Receive Operation
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 107
7.4 Receive Operation
During receive operations, the transmit sequence is reversed. The serial shift register receives data and
transfers it to a parallel receive data register (SCDR) as a complete word. This double buffered operation
allows a character to be shifted in serially while another character is already in the SCDR. An advanced
data recovery scheme distinguishes valid data from noise in the serial data stream. The data input is
selectively sampled to detect receive data, and a majority voting circuit determines the value and integrity
of each bit. See Figure 7-2.
7.5 Wakeup Feature
The wakeup feature reduces SCI service overhead in multiple receiver systems. Software for each
receiver evaluates the first character of each message. The receiver is placed in wakeup mode by writing
a 1 to the RWU bit in the SCCR2 register. While RWU is 1, all of the receiver-related status flags (RDRF,
IDLE, OR, NF, and FE) are inhibited (cannot become set). Although RWU can be cleared by a software
write to SCCR2, to do so would be unusual. Normally, RWU is set by software and is cleared
automatically with hardware. Whenever a new message begins, logic alerts the sleeping receivers to
wake up and evaluate the initial character of the new message.
Two methods of wakeup are available:
• Idle-line wakeup
• Address-mark wakeup
During idle-line wakeup, a sleeping receiver awakens as soon as the RxD line becomes idle. In the
address-mark wakeup, logic 1 in the most significant bit (MSB) of a character wakes up all sleeping
receivers.
7.5.1 Idle-Line Wakeup
To use the receiver wakeup method, establish a software addressing scheme to allow the transmitting
devices to direct a message to individual receivers or to groups of receivers. This addressing scheme can
take any form as long as all transmitting and receiving devices are programmed to understand the same
scheme. Because the addressing information is usually the first frame(s) in a message, receivers that are
not part of the current task do not become burdened with the entire set of addressing frames. All receivers
are awake (RWU = 0) when each message begins. As soon as a receiver determines that the message
is not intended for it, software sets the RWU bit (RWU = 1), which inhibits further flag setting until the RxD
line goes idle at the end of the message. As soon as an idle line is detected by receiver logic, hardware
automatically clears the RWU bit so that the first frame of the next message can be received. This type
of receiver wakeup requires a minimum of one idle-line frame time between messages and no idle time
between frames in a message.
Serial Communications Interface (SCI)
M68HC11E Family Data Sheet, Rev. 5.1
108 Freescale Semiconductor
Figure 7-2. SCI Receiver Block Diagram
FE
NF
OR
IDLE
RDRF
TC
TDRE
SCSR SCI STATUS 1
SBK
RWU
RE
TE
ILIE
RIE
TCIE
TIE
SCCR2 SCI CONTROL 2
WAKE
M
T8
R8
WAKEUP
LOGIC
RIE
OR
ILIE
IDLE
SCI Tx
REQUESTS
SCI INTERRUPT
REQUEST INTERNAL
DATA BUS
PIN BUFFER
AND CONTROL
DDD0
PD0
RxD
SCDR Rx BUFFER
STOP
(8)76543210
10 (11) - BIT
Rx SHIFT REGISTER
READ ONLY
SCCR1 SCI CONTROL 1
RIE
RDRF
START
MSB ALL 1s
DATA
RECOVERY
÷16
RWU
RE
M
DISABLE
DRIVER
RECEIVER
BAUD RATE
CLOCK
8
8
8
SEE NOTE
Note: Refer to Figure B-1. EVBU Schematic Diagram for an example of connecting RxD to a PC.
SCI Error Detection
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 109
7.5.2 Address-Mark Wakeup
The serial characters in this type of wakeup consist of seven (eight if M = 1) information bits and an MSB,
which indicates an address character (when set to 1, or mark). The first character of each message is an
addressing character (MSB = 1). All receivers in the system evaluate this character to determine if the
remainder of the message is directed toward this particular receiver. As soon as a receiver determines
that a message is not intended for it, the receiver activates the RWU function by using a software write to
set the RWU bit. Because setting RWU inhibits receiver-related flags, there is no further software
overhead for the rest of this message.
When the next message begins, its first character has its MSB set, which automatically clears the RWU
bit and enables normal character reception. The first character whose MSB is set is also the first character
to be received after wakeup because RWU gets cleared before the stop bit for that frame is serially
received. This type of wakeup allows messages to include gaps of idle time, unlike the idle-line method,
but there is a loss of efficiency because of the extra bit time for each character (address bit) required for
all characters.
7.6 SCI Error Detection
Three error conditions – SCDR overrun, received bit noise, and framing – can occur during generation of
SCI system interrupts. Three bits (OR, NF, and FE) in the serial communications status register (SCSR)
indicate if one of these error conditions exists.
The overrun error (OR) bit is set when the next byte is ready to be transferred from the receive shift
register to the SCDR and the SCDR is already full (RDRF bit is set). When an overrun error occurs, the
data that caused the overrun is lost and the data that was already in SCDR is not disturbed. The OR is
cleared when the SCSR is read (with OR set), followed by a read of the SCDR.
The noise flag (NF) bit is set if there is noise on any of the received bits, including the start and stop bits.
The NF bit is not set until the RDRF flag is set. The NF bit is cleared when the SCSR is read (with FE
equal to 1) followed by a read of the SCDR.
When no stop bit is detected in the received data character, the framing error (FE) bit is set. FE is set at
the same time as the RDRF. If the byte received causes both framing and overrun errors, the processor
only recognizes the overrun error. The framing error flag inhibits further transfer of data into the SCDR
until it is cleared. The FE bit is cleared when the SCSR is read (with FE equal to 1) followed by a read of
the SCDR.
7.7 SCI Registers
Five addressable registers are associated with the SCI:
• Four control and status registers:
– Serial communications control register 1 (SCCR1)
– Serial communications control register 2 (SCCR2)
– Baud rate register (BAUD)
– Serial communications status register (SCSR)
• One data register:
– Serial communications data register (SCDR)
The SCI registers are the same for all M68HC11 E-series devices with one exception. The SCI system
for MC68HC(7)11E20 contains an extra bit in the BAUD register that provides a greater selection of baud
prescaler rates. Refer to 7.7.5 Baud Rate Register, Figure 7-8, and Figure 7-9.
Serial Communications Interface (SCI)
M68HC11E Family Data Sheet, Rev. 5.1
110 Freescale Semiconductor
7.7.1 Serial Communications Data Register
SCDR is a parallel register that performs two functions:
• The receive data register when it is read
• The transmit data register when it is written
Reads access the receive data buffer and writes access the transmit data buffer. Receive and transmit
are double buffered.
7.7.2 Serial Communications Control Register 1
The SCCR1 register provides the control bits that determine word length and select the method used for
the wakeup feature.
R8 — Receive Data Bit 8
If M bit is set, R8 stores the ninth bit in the receive data character.
T8 — Transmit Data Bit 8
If M bit is set, T8 stores the ninth bit in the transmit data character.
Bit 5 — Unimplemented
Always reads 0
M — Mode Bit (select character format)
0 = Start bit, 8 data bits, 1 stop bit
1 = Start bit, 9 data bits, 1 stop bit
WAKE — Wakeup by Address Mark/Idle Bit
0 = Wakeup by IDLE line recognition
1 = Wakeup by address mark (most significant data bit set)
Bits [2:0] — Unimplemented
Always read 0
Address: $102F
Bit 7654321Bit 0
Read:
R7/T7 R6/T6 R5/T5 R4/T4 R3/T3 R2/T2 R1/T1 R0/T0
Write:
Reset: Indeterminate after reset
Figure 7-3. Serial Communications Data Register (SCDR)
Address: $102C
Bit 7654321Bit 0
Read:
R8 T8 M WAKE
Write:
Reset:I I 000000
I = Indeterminate after reset
= Unimplemented
Figure 7-4. Serial Communications Control Register 1 (SCCR1)
SCI Registers
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 111
7.7.3 Serial Communications Control Register 2
The SCCR2 register provides the control bits that enable or disable individual SCI functions.
TIE — Transmit Interrupt Enable Bit
0 = TDRE interrupts disabled
1 = SCI interrupt requested when TDRE status flag is set
TCIE — Transmit Complete Interrupt Enable Bit
0 = TC interrupts disabled
1 = SCI interrupt requested when TC status flag is set
RIE — Receiver Interrupt Enable Bit
0 = RDRF and OR interrupts disabled
1 = SCI interrupt requested when RDRF flag or the OR status flag is set
ILIE — Idle-Line Interrupt Enable Bit
0 = IDLE interrupts disabled
1 = SCI interrupt requested when IDLE status flag is set
TE — Transmitter Enable Bit
When TE goes from 0 to 1, one unit of idle character time (logic 1) is queued as a preamble.
0 = Transmitter disabled
1 = Transmitter enabled
RE — Receiver Enable Bit
0 = Receiver disabled
1 = Receiver enabled
RWU — Receiver Wakeup Control Bit
0 = Normal SCI receiver
1 = Wakeup enabled and receiver interrupts inhibited
SBK — Send Break
At least one character time of break is queued and sent each time SBK is written to 1. As long as the
SBK bit is set, break characters are queued and sent. More than one break may be sent if the
transmitter is idle at the time the SBK bit is toggled on and off, as the baud rate clock edge could occur
between writing the 1 and writing the 0 to SBK.
0 = Break generator off
1 = Break codes generated
Address: $102D
Bit 7654321Bit 0
Read:
TIE TCIE RIE ILIE TE RE RWU SBK
Write:
Reset:00000000
Figure 7-5. Serial Communications Control Register 2 (SCCR2)
Serial Communications Interface (SCI)
M68HC11E Family Data Sheet, Rev. 5.1
112 Freescale Semiconductor
7.7.4 Serial Communication Status Register
The SCSR provides inputs to the interrupt logic circuits for generation of the SCI system interrupt.
TDRE — Transmit Data Register Empty Flag
This flag is set when SCDR is empty. Clear the TDRE flag by reading SCSR with TDRE set and then
writing to SCDR.
0 = SCDR busy
0 = SCDR empty
TC — Transmit Complete Flag
This flag is set when the transmitter is idle (no data, preamble, or break transmission in progress).
Clear the TC flag by reading SCSR with TC set and then writing to SCDR.
0 = Transmitter busy
1 = Transmitter idle
RDRF — Receive Data Register Full Flag
This flag is set if a received character is ready to be read from SCDR. Clear the RDRF flag by reading
SCSR with RDRF set and then reading SCDR.
0 = SCDR empty
1 = SCDR full
IDLE — Idle Line Detected Flag
This flag is set if the RxD line is idle. Once cleared, IDLE is not set again until the RxD line has been
active and becomes idle again. The IDLE flag is inhibited when RWU = 1. Clear IDLE by reading SCSR
with IDLE set and then reading SCDR.
0 = RxD line active
1 = RxD line idle
OR — Overrun Error Flag
OR is set if a new character is received before a previously received character is read from SCDR.
Clear the OR flag by reading SCSR with OR set and then reading SCDR.
0 = No overrun
1 = Overrun detected
NF — Noise Error Flag
NF is set if majority sample logic detects anything other than a unanimous decision. Clear NF by
reading SCSR with NF set and then reading SCDR.
0 = Unanimous decision
1 = Noise detected
Address: $102E
Bit 7654321Bit 0
Read:
TDRE TC RDRF IDLE OR NF FE
Write:
Reset:11000000
= Unimplemented
Figure 7-6. Serial Communications Status Register (SCSR)
SCI Registers
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 113
FE — Framing Error Flag
FE is set when a 0 is detected where a stop bit was expected. Clear the FE flag by reading SCSR with
FE set and then reading SCDR.
0 = Stop bit detected
1 = Zero detected
Bit 0 — Unimplemented
Always reads 0
7.7.5 Baud Rate Register
Use this register to select different baud rates for the SCI system. The SCP[1:0] (SCP[2:0] in
MC68HC(7)11E20) bits function as a prescaler for the SCR[2:0] bits. Together, these five bits provide
multiple baud rate combinations for a given crystal frequency. Normally, this register is written once during
initialization. The prescaler is set to its fastest rate by default out of reset and can be changed at any time.
Refer to Table 7-1 for normal baud rate selections.
TCLR — Clear Baud Rate Counter Bit (Test)
SCP[2:0] — SCI Baud Rate Prescaler Select Bits
NOTE
SCP2 applies to MC68HC(7)11E20 only. When SCP2 = 1, SCP[1:0] must
equal 0s. Any other values for SCP[1:0] are not decoded in the prescaler
and the results are unpredictable. Refer to Figure 7-8 and Figure 7-9.
RCKB — SCI Baud Rate Clock Check Bit (Test)
See Table 7-1.
Address: $102B
Bit 7654321Bit 0
Read:
TCLR SCP2 SCP1 SCP0 RCKB SCR2 SCR1 SCR0
Write:
Reset:00000UUU
U = Unaffected
Figure 7-7. Baud Rate Register (BAUD)
Serial Communications Interface (SCI)
M68HC11E Family Data Sheet, Rev. 5.1
114 Freescale Semiconductor
Table 7-1. Baud Rate Values
Prescale
Divide
Baud
Set
Divide
Crystal Frequency (MHz)
4.00 4.9152 8.00 10.00 12.00 16.00
Prescaler Selects Bus Frequency (MHz)
SCP2 SCP1 SCP0 SCR2 SCR1 SCR0 1.00 1.23 2.00 2.50 3.00 4.00
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
1
1
1
1
1
1
1
1
1
2
4
8
16
32
64
128
62500
31250
15625
7813
3906
1953
977
488
76800
38400
19200
9600
4800
2400
1200
600
125000
62500
31250
15625
7813
3906
1953
977
156250
78125
39063
19531
9766
4883
2441
1221
187500
93750
46875
23438
11719
5859
2930
1465
250000
125000
62500
31250
15625
7813
3906
1953
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
3
3
3
3
3
3
3
3
1
2
4
8
16
32
64
128
20833
10417
5208
2604
1302
651
326
163
25600
12800
6400
3200
1600
800
400
200
41667
20833
10417
5208
2604
1302
651
326
52083
26042
13021
6510
3255
1628
814
407
62500
31250
15625
7813
3906
1953
977
488
83333
41667
20833
10417
5208
2604
1302
651
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
4
4
4
4
4
4
4
4
1
2
4
8
16
32
64
128
15625
7813
3906
1953
977
488
244
122
19200
9600
4800
2400
1200
600
300
150
31250
15625
7813
3906
1953
977
488
244
39063
19531
9766
4883
2441
1221
610
305
46875
23438
11719
5859
2930
1465
732
366
62500
31250
15625
7813
3906
1953
977
488
0
0
0
0
0
0
0
0
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
13
13
13
13
13
13
13
13
1
2
4
8
16
32
64
128
4808
2404
1202
601
300
150
75
38
5908
2954
1477
738
369
185
92
46
9615
4808
2404
1202
601
300
150
75
12019
6010
3005
1502
751
376
188
94
14423
7212
3606
1803
901
451
225
113
19231
9615
4808
2404
1202
601
300
150
1
1
1
1
1
1
1
1
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
0
1
1
1
1
0
0
1
1
0
0
1
1
0
1
0
1
0
1
0
1
39
39
39
39
39
39
39
39
1
2
4
8
16
32
64
128
1603
801
401
200
100
50
25
13
1969
985
492
246
123
62
31
15
3205
1603
801
401
200
100
50
25
4006
2003
1002
501
250
125
63
31
4808
2404
1202
601
300
150
75
38
6410
3205
1603
801
401
200
100
50
Shaded areas reflect standard baud rates.
On MC68HC(7)11E20 do not set SCP1 or SCP0 when SCP2 is 1.
SCI Registers
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 115
SCR[2:0] — SCI Baud Rate Select Bits
Selects receiver and transmitter bit rate based on output from baud rate prescaler stage. Refer to
Figure 7-8 and Figure 7-9.
The prescaler bits, SCP[2:0], determine the highest baud rate, and the SCR[2:0] bits select an
additional binary submultiple (÷1, ÷2, ÷4, through ÷128) of this highest baud rate. The result of these
two dividers in series is the 16X receiver baud rate clock. The SCR[2:0] bits are not affected by reset
and can be changed at any time, although they should not be changed when any SCI transfer is in
progress.
Figure 7-8 and Figure 7-9 illustrate the SCI baud rate timing chain. The prescaler select bits determine
the highest baud rate. The rate select bits determine additional divide by two stages to arrive at the
receiver timing (RT) clock rate. The baud rate clock is the result of dividing the RT clock by 16.
Figure 7-8. SCI Baud Rate Generator Block Diagram
0:0:0
÷ 20:0:1
÷ 20:1:0
÷ 20:1:1
÷ 21:0:0
÷ 21:0:1
÷ 21:1:0
÷ 2
SCI
TRANSMIT
BAUD RATE
(1X)
SCI
RECEIVE
BAUD RATE
(16X)
÷ 16
1:1:1
SCR[2:0]
÷ 3
0:0
÷ 4÷ 13
0:1 1:0 1:1
OSCILLATOR
AND
CLOCK GENERATOR
(÷4)
SCP[1:0]
INTERNAL BUS CLOCK (PH2)
E
AS
EXTAL
XTAL
Serial Communications Interface (SCI)
M68HC11E Family Data Sheet, Rev. 5.1
116 Freescale Semiconductor
Figure 7-9. MC68HC(7)11E20 SCI Baud Rate
Generator Block Diagram
7.8 Status Flags and Interrupts
The SCI transmitter has two status flags. These status flags can be read by software (polled) to tell when
the corresponding condition exists. Alternatively, a local interrupt enable bit can be set to enable each of
these status conditions to generate interrupt requests when the corresponding condition is present.
Status flags are automatically set by hardware logic conditions, but must be cleared by software, which
provides an interlock mechanism that enables logic to know when software has noticed the status
indication. The software clearing sequence for these flags is automatic. Functions that are normally
performed in response to the status flags also satisfy the conditions of the clearing sequence.
0:0:0
÷ 20:0:1
÷ 20:1:0
÷ 20:1:1
÷ 21:0:0
÷ 21:0:1
÷ 21:1:0
÷ 2
SCI
TRANSMIT
BAUD RATE
(1X)
SCI
RECEIVE
BAUD RATE
(16X)
÷ 16
1:1:1
SCR[2:0]
÷ 3
0:0:0
÷ 4÷ 13
0:0:1 0:1:0 0:1:1
OSCILLATOR
AND
CLOCK GENERATOR
(÷4)
SCP[2:0]*
INTERNAL BUS CLOCK (PH2)
E
AS
EXTAL
XTAL ÷ 39
1:0:0
*SCP2 is present only on MC68HC(7)11E20.
Receiver Flags
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 117
TDRE and TC flags are normally set when the transmitter is first enabled (TE set to 1). The TDRE flag
indicates there is room in the transmit queue to store another data character in the TDR. The TIE bit is
the local interrupt mask for TDRE. When TIE is 0, TDRE must be polled. When TIE and TDRE are 1, an
interrupt is requested.
The TC flag indicates the transmitter has completed the queue. The TCIE bit is the local interrupt mask
for TC. When TCIE is 0, TC must be polled. When TCIE is 1 and TC is 1, an interrupt is requested.
Writing a 0 to TE requests that the transmitter stop when it can. The transmitter completes any
transmission in progress before actually shutting down. Only an MCU reset can cause the transmitter to
stop and shut down immediately. If TE is written to 0 when the transmitter is already idle, the pin reverts
to its general-purpose I/O function (synchronized to the bit-rate clock). If anything is being transmitted
when TE is written to 0, that character is completed before the pin reverts to general-purpose I/O, but any
other characters waiting in the transmit queue are lost. The TC and TDRE flags are set at the completion
of this last character, even though TE has been disabled.
7.9 Receiver Flags
The SCI receiver has five status flags, three of which can generate interrupt requests. The status flags
are set by the SCI logic in response to specific conditions in the receiver. These flags can be read (polled)
at any time by software. Refer to Figure 7-10, which shows SCI interrupt arbitration.
When an overrun takes place, the new character is lost, and the character that was in its way in the
parallel RDR is undisturbed. RDRF is set when a character has been received and transferred into the
parallel RDR. The OR flag is set instead of RDRF if overrun occurs. A new character is ready to be
transferred into RDR before a previous character is read from RDR.
The NF and FE flags provide additional information about the character in the RDR, but do not generate
interrupt requests.
The last receiver status flag and interrupt source come from the IDLE flag. The RxD line is idle if it has
constantly been at logic 1 for a full character time. The IDLE flag is set only after the RxD line has been
busy and becomes idle, which prevents repeated interrupts for the whole time RxD remains idle.
Serial Communications Interface (SCI)
M68HC11E Family Data Sheet, Rev. 5.1
118 Freescale Semiconductor
Figure 7-10. Interrupt Source Resolution Within SCI
FLAG Y
N
OR = 1? Y
N
Y
N
TDRE = 1?
TC = 1?
Y
N
IDLE = 1?
Y
N
Y
N
Y
N
Y
N
ILIE = 1?
RIE = 1?
TIE = 1?
BEGIN
RE = 1? Y
N
Y
N
TE = 1?
TCIE = 1?
Y
N
RE = 1?
Y
N
RDRF = 1?
VALID SCI REQUEST
NO
VALID SCI REQUEST
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 119
Chapter 8
Serial Peripheral Interface (SPI)
8.1 Introduction
The serial peripheral interface (SPI), an independent serial communications subsystem, allows the MCU
to communicate synchronously with peripheral devices, such as:
• Frequency synthesizers
• Liquid crystal display (LCD) drivers
• Analog-to-digital (A/D) converter subsystems
• Other microprocessors
The SPI is also capable of inter-processor communication in a multiple master system. The SPI system
can be configured as either a master or a slave device. When configured as a master, data transfer rates
can be as high as one-half the E-clock rate (1.5 Mbits per second for a 3-MHz bus frequency). When
configured as a slave, data transfers can be as fast as the E-clock rate (3 Mbits per second for a 3-MHz
bus frequency).
8.2 Functional Description
The central element in the SPI system is the block containing the shift register and the read data buffer.
The system is single buffered in the transmit direction and double buffered in the receive direction. This
means that new data for transmission cannot be written to the shifter until the previous transfer is
complete; however, received data is transferred into a parallel read data buffer so the shifter is free to
accept a second serial character. As long as the first character is read out of the read data buffer before
the next serial character is ready to be transferred, no overrun condition occurs. A single MCU register
address is used for reading data from the read data buffer and for writing data to the shifter.
The SPI status block represents the SPI status functions (transfer complete, write collision, and mode
fault) performed by the serial peripheral status register (SPSR). The SPI control block represents those
functions that control the SPI system through the serial peripheral control register (SPCR).
Refer to Figure 8-1, which shows the SPI block diagram.
8.3 SPI Transfer Formats
During an SPI transfer, data is simultaneously transmitted and received. A serial clock line synchronizes
shifting and sampling of the information on the two serial data lines. A slave select line allows individual
selection of a slave SPI device; slave devices that are not selected do not interfere with SPI bus activities.
On a master SPI device, the select line can optionally be used to indicate a multiple master bus
contention. Refer to Figure 8-2.
Serial Peripheral Interface (SPI)
M68HC11E Family Data Sheet, Rev. 5.1
120 Freescale Semiconductor
Figure 8-1. SPI Block Diagram
8.4 Clock Phase and Polarity Controls
Software can select one of four combinations of serial clock phase and polarity using two bits in the SPI
control register (SPCR). The clock polarity is specified by the CPOL control bit, which selects an active
high or active low clock, and has no significant effect on the transfer format. The clock phase (CPHA)
control bit selects one of two different transfer formats. The clock phase and polarity should be identical
for the master SPI device and the communicating slave device. In some cases, the phase and polarity
are changed between transfers to allow a master device to communicate with peripheral slaves having
different requirements.
When CPHA equals 0, the SS line must be negated and reasserted between each successive serial byte.
Also, if the slave writes data to the SPI data register (SPDR) while SS is low, a write collision error results.
When CPHA equals 1, the SS line can remain low between successive transfers.
8--BIT SHIFT REGISTER
READ DATA BUFFER
MSB LSB
MISO
PD2
MOSI
PD3
SCK
PD4
SS
PD5
DIVIDER
÷2÷4÷16 ÷32
INTERNAL
MCU CLOCK
SELECT
S
M
M
S
S
M
PIN CONTROL LOGIC
CLOCK
LOGIC
CLOCK
SPIF
SPE
DWOM
INSTR
CPOL
CPHA
SPRI
SPRO
SPI CONTROL REGISTER
MSTD
SEC
DWOM
SPRI
SPRO
MSTR
SPE
SPI CONTROL
SPIF
WCOL
MODE
SPI STATUS REGISTER
SPI INTERRUPT
REQUEST
INTERNAL
DATA BUS
SPI Signals
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 121
Figure 8-2. SPI Transfer Format
8.5 SPI Signals
This subsection contains descriptions of the four SPI signals:
• Master in/slave out (MISO)
• Master out/slave in (MOSI)
• Serial clock (SCK)
• Slave select (SS)
Any SPI output line must have its corresponding data direction bit in DDRD register set. If the DDR bit is
clear, that line is disconnected from the SPI logic and becomes a general-purpose input. All SPI input lines
are forced to act as inputs regardless of the state of the corresponding DDR bits in DDRD register.
8.5.1 Master In/Slave Out
MISO is one of two unidirectional serial data signals. It is an input to a master device and an output from
a slave device. The MISO line of a slave device is placed in the high-impedance state if the slave device
is not selected.
8.5.2 Master Out/Slave In
The MOSI line is the second of the two unidirectional serial data signals. It is an output from a master
device and an input to a slave device. The master device places data on the MOSI line a half-cycle before
the clock edge that the slave device uses to latch the data.
23456781
SCK (CPOL = 1)
SCK (CPOL = 0)
SCK CYCLE #
SS (TO SLAVE)
654321 LSBMSB
MSB654321LSB
1
2
3
5
4
SLAVE CPHA = 1 TRANSFER IN PROGRESS
MASTER TRANSFER IN PROGRESS
SLAVE CPHA = 0 TRANSFER IN PROGRESS
1. SS ASSERTED
2. MASTER WRITES TO SPDR
3. FIRST SCK EDGE
4. SPIF SET
5. SS NEGATED
SAMPLE INPUT
DATA OUT
(CPHA = 0)
SAMPLE INPUT
DATA OUT
(CPHA = 1)
Serial Peripheral Interface (SPI)
M68HC11E Family Data Sheet, Rev. 5.1
122 Freescale Semiconductor
8.5.3 Serial Clock
SCK, an input to a slave device, is generated by the master device and synchronizes data movement in
and out of the device through the MOSI and MISO lines. Master and slave devices are capable of
exchanging a byte of information during a sequence of eight clock cycles.
Four possible timing relationships can be chosen by using control bits CPOL and CPHA in the serial
peripheral control register (SPCR). Both master and slave devices must operate with the same timing.
The SPI clock rate select bits, SPR[1:0], in the SPCR of the master device, select the clock rate. In a slave
device, SPR[1:0] have no effect on the operation of the SPI.
8.5.4 Slave Select
The slave select (SS) input of a slave device must be externally asserted before a master device can
exchange data with the slave device. SS must be low before data transactions and must stay low for the
duration of the transaction.
The SS line of the master must be held high. If it goes low, a mode fault error flag (MODF) is set in the
serial peripheral status register (SPSR). To disable the mode fault circuit, write a 1 in bit 5 of the port D
data direction register. This sets the SS pin to act as a general-purpose output rather than the dedicated
input to the slave select circuit, thus inhibiting the mode fault flag. The other three lines are dedicated to
the SPI whenever the serial peripheral interface is on.
The state of the master and slave CPHA bits affects the operation of SS. CPHA settings should be
identical for master and slave. When CPHA = 0, the shift clock is the OR of SS with SCK. In this clock
phase mode, SS must go high between successive characters in an SPI message. When CPHA = 1, SS
can be left low between successive SPI characters. In cases where there is only one SPI slave MCU, its
SS line can be tied to VSS as long as only CPHA = 1 clock mode is used.
8.6 SPI System Errors
Two system errors can be detected by the SPI system. The first type of error arises in a multiple-master
system when more than one SPI device simultaneously tries to be a master. This error is called a mode
fault. The second type of error, write collision, indicates that an attempt was made to write data to the
SPDR while a transfer was in progress.
When the SPI system is configured as a master and the SS input line goes to active low, a mode fault
error has occurred — usually because two devices have attempted to act as master at the same time. In
cases where more than one device is concurrently configured as a master, there is a chance of contention
between two pin drivers. For push-pull CMOS drivers, this contention can cause permanent damage. The
mode fault mechanism attempts to protect the device by disabling the drivers. The MSTR control bit in the
SPCR and all four DDRD control bits associated with the SPI are cleared and an interrupt is generated
subject to masking by the SPIE control bit and the I bit in the CCR.
Other precautions may need to be taken to prevent driver damage. If two devices are made masters at
the same time, mode fault does not help protect either one unless one of them selects the other as slave.
The amount of damage possible depends on the length of time both devices attempt to act as master.
A write collision error occurs if the SPDR is written while a transfer is in progress. Because the SPDR is
not double buffered in the transmit direction, writes to SPDR cause data to be written directly into the SPI
shift register. Because this write corrupts any transfer in progress, a write collision error is generated. The
transfer continues undisturbed, and the write data that caused the error is not written to the shifter.
SPI Registers
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 123
A write collision is normally a slave error because a slave has no control over when a master initiates a
transfer. A master knows when a transfer is in progress, so there is no reason for a master to generate a
write-collision error, although the SPI logic can detect write collisions in both master and slave devices.
The SPI configuration determines the characteristics of a transfer in progress. For a master, a transfer
begins when data is written to SPDR and ends when SPIF is set. For a slave with CPHA equal to 0, a
transfer starts when SS goes low and ends when SS returns high. In this case, SPIF is set at the middle
of the eighth SCK cycle when data is transferred from the shifter to the parallel data register, but the
transfer is still in progress until SS goes high. For a slave with CPHA equal to 1, transfer begins when the
SCK line goes to its active level, which is the edge at the beginning of the first SCK cycle. The transfer
ends in a slave in which CPHA equals 1 when SPIF is set.
8.7 SPI Registers
The three SPI registers are:
• Serial peripheral control register (SPCR)
• Serial peripheral status register (SPSR)
• Serial peripheral data register (SPDR)
These registers provide control, status, and data storage functions.
8.7.1 Serial Peripheral Control Register
SPIE — Serial Peripheral Interrupt Enable Bit
Set the SPE bit to 1 to request a hardware interrupt sequence each time the SPIF or MODF status flag
is set. SPI interrupts are inhibited if this bit is clear or if the I bit in the condition code register is 1.
0 = SPI system interrupts disabled
1 = SPI system interrupts enabled
SPE — Serial Peripheral System Enable Bit
When the SPE bit is set, the port D bit 2, 3, 4, and 5 pins are dedicated to the SPI function. If the SPI
is in the master mode and DDRD bit 5 is set, then the port D bit 5 pin becomes a general-purpose
output instead of the SS input.
0 = SPI system disabled
1 = SPI system enabled
DWOM — Port D Wired-OR Mode Bit
DWOM affects all port D pins.
0 = Normal CMOS outputs
1 = Open-drain outputs
Address: $1028
Bit 7654321Bit 0
Read:
SPIE SPE DWOM MSTR CPOL CPHA SPR1 SPR0
Write:
Reset:000001UU
U = Unaffected
Figure 8-3. Serial Peripheral Control Register (SPCR)
Serial Peripheral Interface (SPI)
M68HC11E Family Data Sheet, Rev. 5.1
124 Freescale Semiconductor
MSTR — Master Mode Select Bit
It is customary to have an external pullup resistor on lines that are driven by open-drain devices.
0 = Slave mode
1 = Master mode
CPOL — Clock Polarity Bit
When the clock polarity bit is cleared and data is not being transferred, the SCK pin of the master
device has a steady state low value. When CPOL is set, SCK idles high. Refer to Figure 8-2 and 8.4
Clock Phase and Polarity Controls.
CPHA — Clock Phase Bit
The clock phase bit, in conjunction with the CPOL bit, controls the clock-data relationship between
master and slave. The CPHA bit selects one of two different clocking protocols. Refer to Figure 8-2
and 8.4 Clock Phase and Polarity Controls.
SPR[1:0] — SPI Clock Rate Select Bits
These two bits select the SPI clock (SCK) rate when the device is configured as master. When the
device is configured as slave, these bits have no effect. Refer to Table 8-1.
8.7.2 Serial Peripheral Status Register
SPIF — SPI Interrupt Complete Flag
SPIF is set upon completion of data transfer between the processor and the external device. If SPIF
goes high, and if SPIE is set, a serial peripheral interrupt is generated. To clear the SPIF bit, read the
SPSR with SPIF set, then access the SPDR. Unless SPSR is read (with SPIF set) first, attempts to
write SPDR are inhibited.
WCOL — Write Collision Bit
Clearing the WCOL bit is accomplished by reading the SPSR (with WCOL set) followed by an access
of SPDR. Refer to 8.5.4 Slave Select and 8.6 SPI System Errors.
0 = No write collision
1 = Write collision
Table 8-1. SPI Clock Rates
SPR[1:0] Divide
E Clock By
Frequency at
E = 1 MHz
(Baud)
Frequency at
E = 2 MHz
(Baud)
Frequency at
E = 3 MHz (
Baud)
Frequency at
E = 4 MHz
(Baud)
0 0 2 500 kHz 1.0 MHz 1.5 MHz 2 MHz
0 1 4 250 kHz 500 kHz 750 kHz 1 MHz
1 0 16 62.5 kHz 125 kHz 187.5 kHz 250 kHz
1 1 32 31.3 kHz 62.5 kHz 93.8 kHz 125 kHz
Address: $1029
Bit 7654321Bit 0
Read:
SPIF WCOL MODF
Write:
Reset:00000000
= Unimplemented
Figure 8-4. Serial Peripheral Status Register (SPSR)
SPI Registers
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 125
Bit 5 — Unimplemented
Always reads 0
MODF — Mode Fault Bit
To clear the MODF bit, read the SPSR (with MODF set), then write to the SPCR. Refer to 8.5.4 Slave
Select and 8.6 SPI System Errors.
0 = No mode fault
1 = Mode fault
Bits [3:0] — Unimplemented
Always read 0
8.7.3 Serial Peripheral Data I/O Register
The SPDR is used when transmitting or receiving data on the serial bus. Only a write to this register
initiates transmission or reception of a byte, and this only occurs in the master device. At the completion
of transferring a byte of data, the SPIF status bit is set in both the master and slave devices.
A read of the SPDR is actually a read of a buffer. To prevent an overrun and the loss of the byte that
caused the overrun, the first SPIF must be cleared by the time a second transfer of data from the shift
register to the read buffer is initiated.
SPI is double buffered in and single buffered out.
Address: $102A
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
Figure 8-5. Serial Peripheral Data I/O Register (SPDR)
Serial Peripheral Interface (SPI)
M68HC11E Family Data Sheet, Rev. 5.1
126 Freescale Semiconductor
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 127
Chapter 9
Timing Systems
9.1 Introduction
The M68HC11 timing system is composed of five clock divider chains. The main clock divider chain
includes a 16-bit free-running counter, which is driven by a programmable prescaler. The main timer’s
programmable prescaler provides one of the four clocking rates to drive the 16-bit counter. Two prescaler
control bits select the prescale rate.
The prescaler output divides the system clock by 1, 4, 8, or 16. Taps off of this main clocking chain drive
circuitry that generates the slower clocks used by the pulse accumulator, the real-time interrupt (RTI), and
the computer operating properly (COP) watchdog subsystems, also described in this section. Refer to
Figure 9-1.
All main timer system activities are referenced to this free-running counter. The counter begins
incrementing from $0000 as the MCU comes out of reset and continues to the maximum count, $FFFF.
At the maximum count, the counter rolls over to $0000, sets an overflow flag, and continues to increment.
As long as the MCU is running in a normal operating mode, there is no way to reset, change, or interrupt
the counting. The capture/compare subsystem features three input capture channels, four output
compare channels, and one channel that can be selected to perform either input capture or output
compare. Each of the three input capture functions has its own 16-bit input capture register (time capture
latch) and each of the output compare functions has its own 16-bit compare register. All timer functions,
including the timer overflow and RTI, have their own interrupt controls and separate interrupt vectors.
The pulse accumulator contains an 8-bit counter and edge select logic. The pulse accumulator can
operate in either event counting mode or gated time accumulation mode. During event counting mode,
the pulse accumulator’s 8-bit counter increments when a specified edge is detected on an input signal.
During gated time accumulation mode, an internal clock source increments the 8-bit counter while an
input signal has a predetermined logic level.
The real-time interrupt (RTI) is a programmable periodic interrupt circuit that permits pacing the execution
of software routines by selecting one of four interrupt rates.
The COP watchdog clock input (E ÷ 215) is tapped off of the free-running counter chain. The COP
automatically times out unless it is serviced within a specific time by a program reset sequence. If the COP
is allowed to time out, a reset is generated, which drives the RESET pin low to reset the MCU and the
external system. Refer to Table 9-1 for crystal-related frequencies and periods.
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
128 Freescale Semiconductor
Figure 9-1. Timer Clock Divider Chains
E SERIES TIM DIV CHAIN
OSCILLATOR AND
CLOCK GENERATOR AS
E CLOCK
SPI
SCI RECEIVER CLOCK
SCI TRANSMIT CLOCK
E ÷ 26PULSE ACCUMULATOR
TCNT
TOF
REAL-TIME INTERRUPTE ÷ 213
÷ 4
E÷215
RQ
QS
RQ
QS
FORCE
COP
RESET
SYSTEM
RESET
CLEAR COP
TIMER
FF2
FF1
(DIVIDE BY FOUR)
INTERNAL BUS CLOCK (PH2)
IC/OC
÷16
CR[1:0]
PRESCALER
(÷1, 4, 16, 64)
PRESCALER
(÷ 2, 4, 16, 32)
SPR[1:0]
PRESCALER
(÷ 1, 3, 4, 13)
SCP[1:0]
PRESCALER
(÷÷ 1, 2, 4, 8)
RTR[1:0]
PRESCALER
(÷ 1, 2, 4,....128)
SCR[2:0]
PRESCALER
(÷ 1, 4, 8, 16)
PR[1:0]
÷39
SCP2*
* SCP2 present on MC68HC(7)11E20 only
Timer Structure
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 129
9.2 Timer Structure
Figure 9-2 shows the capture/compare system block diagram. The port A pin control block includes logic
for timer functions and for general-purpose I/O. For pins PA3, PA2, PA1, and PA0, this block contains
both the edge-detection logic and the control logic that enables the selection of which edge triggers an
input capture. The digital level on PA[3:0] can be read at any time (read PORTA register), even if the pin
is being used for the input capture function. Pins PA[6:3] are used for either general-purpose I/O, or as
output compare pins. When one of these pins is being used for an output compare function, it cannot be
written directly as if it were a general-purpose output. Each of the output compare functions (OC[5:2]) is
related to one of the port A output pins. Output compare one (OC1) has extra control logic, allowing it
optional control of any combination of the PA[7:3] pins. The PA7 pin can be used as a general-purpose
I/O pin, as an input to the pulse accumulator, or as an OC1 output pin.
9.3 Input Capture
The input capture function records the time an external event occurs by latching the value of the
free-running counter when a selected edge is detected at the associated timer input pin. Software can
store latched values and use them to compute the periodicity and duration of events. For example, by
storing the times of successive edges of an incoming signal, software can determine the period and pulse
width of a signal. To measure period, two successive edges of the same polarity are captured. To
measure pulse width, two alternate polarity edges are captured.
In most cases, input capture edges are asynchronous to the internal timer counter, which is clocked
relative to an internal clock (PH2). These asynchronous capture requests are synchronized to PH2 so that
the latching occurs on the opposite half cycle of PH2 from when the timer counter is being incremented.
This synchronization process introduces a delay from when the edge occurs to when the counter value is
detected. Because these delays offset each other when the time between two edges is being measured,
the delay can be ignored. When an input capture is being used with an output compare, there is a similar
delay between the actual compare point and when the output pin changes state.
Table 9-1. Timer Summary
XTAL Frequencies
Control Bits
PR1, PR0
4.0 MHz 8.0 MHz 12.0 MHz Other Rates
1.0 MHz 2.0 MHz 3.0 MHz (E)
1000 ns 500 ns 333 ns (1/E)
Main Timer Count Rates
0 0
1 count —
overflow —
1000 ns
65.536 ms
500 ns
32.768 ms
333 ns
21.845 ms
(E/1)
(E/216)
0 1
1 count —
overflow —
4.0 µs
262.14 ms
2.0 µs
131.07 ms
1.333 µs
87.381 ms
(E/4)
(E/218)
1 0
1 count —
overflow —
8.0 µs
524.29 ms
4.0 µs
262.14 ms
2.667 µs
174.76 ms
(E/8)
(E/219)
1 1
1 count —
overflow —
16.0 µs
1.049 s
8.0 µs
524.29 ms
5.333 µs
349.52 ms
(E/16)
(E/220)
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
130 Freescale Semiconductor
Figure 9-2. Capture/Compare Block Diagram
CAPTURE COMPARE BLOCK
MCU
E CLK
16-BIT LATCH CLK
PA0/IC3
4
3
5
6
7
8
2
1
BIT 7
BIT 6
BIT 5
BIT 4
BIT 3
BIT 2
BIT 1
BIT 0
PORT A
PIN CONTROL
OC1I
OC2I
OC3I
OC4I
I4/O5I
IC1I
IC2I
IC3I
TFLG 1
STATUS
FLAGS
FOC1
FOC2
FOC3
FOC4
FOC5
OC1F
OC2F
OC3F
OC4F
I4/O5F
IC1F
IC2F
IC3F
PA1/IC2
PA2/IC1
PA3/OC5/
IC4/OC1
PA4/OC4/
OC1
PA5/OC3/
OC1
PA6/OC2/
OC1
PA7/OC1/
PAI
I4/O5
16-BIT COMPARATOR =
TOC1 (HI) TOC1 (LO)
16-BIT COMPARATOR =
TOC2 (HI) TOC2 (LO)
16-BIT COMPARATOR =
TOC3 (HI) TOC3 (LO)
16-BIT COMPARATOR =
TOC4 (HI) TOC4 (LO)
16-BIT LATCH
TIC1 (HI) TIC1 (LO)
CLK
16-BIT LATCH
TIC2 (HI) TIC2 (LO)
CLK
16-BIT LATCH
TIC3 (HI) TIC3 (LO)
CLK
16-BIT COMPARATOR =
TI4/O5 (HI) TI4/O5 (LO)
16-BIT FREE-RUNNING
COUNTER
TCNT (HI) TCNT (LO) 9
TOI
TOF
INTERRUPT REQUESTS
(FURTHER QUALIFIED BY
I BIT IN CCR)
TAPS FOR RTI,
COP WATCHDOG, AND
PULSE ACCUMULATOR
PRESCALER
DIVIDE BY
1, 4, 8, OR 16
PR1 PR0
16-BIT TIMER BUS
OC5
IC4
TO PULSE
ACCUMULATOR
TMSK 1
INTERRUPT
ENABLES
CFORC
FORCE OUTPUT
COMPARE
PIN
FUNCTIONS
Input Capture
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 131
The control and status bits that implement the input capture functions are contained in:
• Pulse accumulator control register (PACTL)
• Timer control 2 register (TCTL2)
• Timer interrupt mask 1 register (TMSK1)
• Timer interrupt flag 2 register (TFLG1)
To configure port A bit 3 as an input capture, clear the DDRA3 bit of the PACTL register. Note that this bit
is cleared out of reset. To enable PA3 as the fourth input capture, set the I4/O5 bit in the PACTL register.
Otherwise, PA3 is configured as a fifth output compare out of reset, with bit I4/O5 being cleared. If the
DDRA3 bit is set (configuring PA3 as an output), and IC4 is enabled, then writes to PA3 cause edges on
the pin to result in input captures. Writing to TI4/O5 has no effect when the TI4/O5 register is acting as IC4.
9.3.1 Timer Control Register 2
Use the control bits of this register to program input capture functions to detect a particular edge polarity
on the corresponding timer input pin. Each of the input capture functions can be independently configured
to detect rising edges only, falling edges only, any edge (rising or falling), or to disable the input capture
function. The input capture functions operate independently of each other and can capture the same
TCNT value if the input edges are detected within the same timer count cycle.
EDGxB and EDGxA — Input Capture Edge Control Bits
There are four pairs of these bits. Each pair is cleared to 0 by reset and must be encoded to configure
the corresponding input capture edge detector circuit. IC4 functions only if the I4/O5 bit in the PACTL
register is set. Refer to Table 9-2 for timer control configuration.
9.3.2 Timer Input Capture Registers
When an edge has been detected and synchronized, the 16-bit free-running counter value is transferred
into the input capture register pair as a single 16-bit parallel transfer. Timer counter value captures and
timer counter incrementing occur on opposite half-cycles of the phase 2 clock so that the count value is
stable whenever a capture occurs. The timer input capture registers are not affected by reset. Input
capture values can be read from a pair of 8-bit read-only registers. A read of the high-order byte of an
Address: $1021
Bit 7654321Bit 0
Read:
EDG4B EDG4A EDG1B EDG1A EDG2B EDG2A EDG3B EDG3A
Write:
Reset:00000000
Figure 9-3. Timer Control Register 2 (TCTL2)
Table 9-2. Timer Control Configuration
EDGxB EDGxA Configuration
0 0 Capture disabled
0 1 Capture on rising edges only
1 0 Capture on falling edges only
1 1 Capture on any edge
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
132 Freescale Semiconductor
input capture register pair inhibits a new capture transfer for one bus cycle. If a double-byte read
instruction, such as load double accumulator D (LDD), is used to read the captured value, coherency is
assured. When a new input capture occurs immediately after a high-order byte read, transfer is delayed
for an additional cycle but the value is not lost.
Register name: Timer Input Capture 1 Register (High) Address: $1010
Bit 7654321Bit 0
Read:
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: Indeterminate after reset
Register name: Timer Input Capture 1 Register (Low) Address: $1011
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
Figure 9-4. Timer Input Capture 1 Register Pair (TIC1)
Register name: Timer Input Capture 2 Register (High) Address: $1012
Bit 7654321Bit 0
Read:
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: Indeterminate after reset
Register name: Timer Input Capture 2 Register (Low) Address: $1013
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
Figure 9-5. Timer Input Capture 2 Register Pair (TIC2)
Register name: Timer Input Capture 3 Register (High) Address: $1014
Bit 7654321Bit 0
Read:
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: Indeterminate after reset
Register name: Timer Input Capture 3 Register (Low) Address: $1015
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
Figure 9-6. Timer Input Capture 3 Register Pair (TIC3)
Output Compare
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 133
9.3.3 Timer Input Capture 4/Output Compare 5 Register
Use TI4/O5 as either an input capture register or an output compare register, depending on the function
chosen for the PA3 pin. To enable it as an input capture pin, set the I4/O5 bit in the pulse accumulator
control register (PACTL) to logic level 1. To use it as an output compare register, set the I4/O5 bit to a
logic level 0. Refer to 9.7 Pulse Accumulator.
9.4 Output Compare
Use the output compare (OC) function to program an action to occur at a specific time — when the 16-bit
counter reaches a specified value. For each of the five output compare functions, there is a separate
16-bit compare register and a dedicated 16-bit comparator. The value in the compare register is
compared to the value of the free-running counter on every bus cycle. When the compare register
matches the counter value, an output compare status flag is set. The flag can be used to initiate the
automatic actions for that output compare function.
To produce a pulse of a specific duration, write a value to the output compare register that represents the
time the leading edge of the pulse is to occur. The output compare circuit is configured to set the
appropriate output either high or low, depending on the polarity of the pulse being produced. After a match
occurs, the output compare register is reprogrammed to change the output pin back to its inactive level
at the next match. A value representing the width of the pulse is added to the original value, and then
written to the output compare register. Because the pin state changes occur at specific values of the
free-running counter, the pulse width can be controlled accurately at the resolution of the free-running
counter, independent of software latencies. To generate an output signal of a specific frequency and duty
cycle, repeat this pulse-generating procedure.
The five 16-bit read/write output compare registers are: TOC1, TOC2, TOC3, and TOC4, and the TI4/O5.
TI4/O5 functions under software control as either IC4 or OC5. Each of the OC registers is set to $FFFF
on reset. A value written to an OC register is compared to the free-running counter value during each
E-clock cycle. If a match is found, the particular output compare flag is set in timer interrupt flag register
1 (TFLG1). If that particular interrupt is enabled in the timer interrupt mask register 1 (TMSK1), an interrupt
is generated. In addition to an interrupt, a specified action can be initiated at one or more timer output
pins. For OC[5:2], the pin action is controlled by pairs of bits (OMx and OLx) in the TCTL1 register. The
output action is taken on each successful compare, regardless of whether or not the OCxF flag in the
TFLG1 register was previously cleared.
Register name: Timer Input Capture 4/Output Compare 5 (High) Address: $101E
Bit 7654321Bit 0
Read:
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 11111111
Register name: Timer Input Capture 4/Output Compare 5 (Low) Address: $101F
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 11111111
Figure 9-7. Timer Input Capture 4/Output
Compare 5 Register Pair (TI4/O5)
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
134 Freescale Semiconductor
OC1 is different from the other output compares in that a successful OC1 compare can affect any or all
five of the OC pins. The OC1 output action taken when a match is found is controlled by two 8-bit registers
with three bits unimplemented: the output compare 1 mask register, OC1M, and the output compare 1
data register, OC1D. OC1M specifies which port A outputs are to be used, and OC1D specifies what data
is placed on these port pins.
9.4.1 Timer Output Compare Registers
All output compare registers are 16-bit read-write. Each is initialized to $FFFF at reset. If an output
compare register is not used for an output compare function, it can be used as a storage location. A write
to the high-order byte of an output compare register pair inhibits the output compare function for one bus
cycle. This inhibition prevents inappropriate subsequent comparisons. Coherency requires a complete
16-bit read or write. However, if coherency is not needed, byte accesses can be used.
For output compare functions, write a comparison value to output compare registers TOC1–TOC4 and
TI4/O5. When TCNT value matches the comparison value, specified pin actions occur.
Register name: Timer Output Compare 1 Register (High) Address: $1016
Bit 7654321Bit 0
Read:
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 11111111
Register name: Timer Output Compare 1 Register (Low) Address: $1017
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 11111111
Figure 9-8. Timer Output Compare 1 Register Pair (TOC1)
Register name: Timer Output Compare 2 Register (High) Address: $1018
Bit 7654321Bit 0
Read:
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 11111111
Register name: Timer Output Compare 2 Register (Low) Address: $1019
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 11111111
Figure 9-9. Timer Output Compare 2 Register Pair (TOC2)
Output Compare
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 135
9.4.2 Timer Compare Force Register
The CFORC register allows forced early compares. FOC[1:5] correspond to the five output compares.
These bits are set for each output compare that is to be forced. The action taken as a result of a forced
compare is the same as if there were a match between the OCx register and the free-running counter,
except that the corresponding interrupt status flag bits are not set. The forced channels trigger their
programmed pin actions to occur at the next timer count transition after the write to CFORC.
The CFORC bits should not be used on an output compare function that is programmed to toggle its
output on a successful compare because a normal compare that occurs immediately before or after the
force can result in an undesirable operation.
Register name: Timer Output Compare 3 Register (High) Address: $101A
Bit 7654321Bit 0
Read:
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 11111111
Register name: Timer Output Compare 3 Register (Low) Address: $101B
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 11111111
Figure 9-10. Timer Output Compare 3 Register Pair (TOC3)
Register name: Timer Output Compare 4 Register (High) Address: $101C
Bit 7654321Bit 0
Read:
Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 11111111
Register name: Timer Output Compare 4 Register (Low) Address: $101D
Bit 7654321Bit 0
Read:
Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 11111111
Figure 9-11. Timer Output Compare 4 Register Pair (TOC4)
Address: $100B
Bit 7654321Bit 0
Read:
FOC1 FOC2 FOC3 FOC4 FOC5
Write:
Reset:00000000
= Unimplemented
Figure 9-12. Timer Compare Force Register (CFORC)
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
136 Freescale Semiconductor
FOC[1:5] — Force Output Comparison Bit
When the FOC bit associated with an output compare circuit is set, the output compare circuit
immediately performs the action it is programmed to do when an output match occurs.
0 = Not affected
1 = Output x action occurs
Bits [2:0] — Unimplemented
Always read 0
9.4.3 Output Compare Mask Register
Use OC1M with OC1 to specify the bits of port A that are affected by a successful OC1 compare. The bits
of the OC1M register correspond to PA[7:3].
OC1M[7:3] — Output Compare Masks
0 = OC1 disabled
1 = OC1 enabled to control the corresponding pin of port A
Bits [2:0] — Unimplemented
Always read 0
9.4.4 Output Compare Data Register
Use this register with OC1 to specify the data that is to be stored on the affected pin of port A after a
successful OC1 compare. When a successful OC1 compare occurs, a data bit in OC1D is stored in the
corresponding bit of port A for each bit that is set in OC1M.
If OC1Mx is set, data in OC1Dx is output to port A bit x on successful OC1 compares.
Bits [2:0] — Unimplemented
Always read 0
Address: $100C
Bit 7654321Bit 0
Read:
OC1M7 OC1M6 OC1M5 OC1M4 OC1M3
Write:
Reset:00000000
= Unimplemented
Figure 9-13. Output Compare 1 Mask Register (OC1M)
Address: $100D
Bit 7654321Bit 0
Read:
OC1D7 OC1D6 OC1D5 OC1D4 OC1D3
Write:
Reset:00000000
= Unimplemented
Figure 9-14. Output Compare 1 Data Register (OC1D)
Output Compare
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 137
9.4.5 Timer Counter Register
The 16-bit read-only TCNT register contains the prescaled value of the 16-bit timer. A full counter read
addresses the most significant byte (MSB) first. A read of this address causes the least significant byte
(LSB) to be latched into a buffer for the next CPU cycle so that a double-byte read returns the full 16-bit
state of the counter at the time of the MSB read cycle.
9.4.6 Timer Control Register 1
The bits of this register specify the action taken as a result of a successful OCx compare.
OM[2:5] — Output Mode Bits
OL[2:5] — Output Level Bits
These control bit pairs are encoded to specify the action taken after a successful OCx compare. OC5
functions only if the I4/O5 bit in the PACTL register is clear. Refer to Table 9-3 for the coding.
Register name: Timer Counter Register (High) Address: $100E
Bit 7654321Bit 0
Read: Bit 15 Bit 14 Bit 13 Bit 12 Bit 11 Bit 10 Bit 9 Bit 8
Write:
Reset: 00000000
Register name: Timer Counter Register (Low) Address: $100F
Bit 7654321Bit 0
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: 00000000
= Unimplemented
Figure 9-15. Timer Counter Register (TCNT)
Address: $1020
Bit 7654321Bit 0
Read:
OM2OL2OM3OL3OM4OL4OM5OL5
Write:
Reset:00000000
Figure 9-16. Timer Control Register 1 (TCTL1)
Table 9-3. Timer Output Compare Actions
OMx OLx Action Taken on Successful Compare
0 0 Timer disconnected from output pin logic
0 1 Toggle OCx output line
1 0 Clear OCx output line to 0
1 1 Set OCx output line to 1
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
138 Freescale Semiconductor
9.4.7 Timer Interrupt Mask 1 Register
Use this 8-bit register to enable or inhibit the timer input capture and output compare interrupts.
OC1I–OC4I — Output Compare x Interrupt Enable Bits
If the OCxI enable bit is set when the OCxF flag bit is set, a hardware interrupt sequence is requested.
I4/O5I — Input Capture 4/Output Compare 5 Interrupt Enable Bit
When I4/O5 in PACTL is 1, I4/O5I is the input capture 4 interrupt enable bit. When I4/O5 in PACTL is
0, I4/O5I is the output compare 5 interrupt enable bit.
IC1I–IC3I — Input Capture x Interrupt Enable Bits
If the ICxI enable bit is set when the ICxF flag bit is set, a hardware interrupt sequence is requested.
NOTE
Bits in TMSK1 correspond bit for bit with flag bits in TFLG1. Bits in TMSK1
enable the corresponding interrupt sources.
9.4.8 Timer Interrupt Flag 1 Register
Bits in this register indicate when timer system events have occurred. Coupled with the bits of TMSK1,
the bits of TFLG1 allow the timer subsystem to operate in either a polled or interrupt driven system. Each
bit of TFLG1 corresponds to a bit in TMSK1 in the same position.
Clear flags by writing a 1 to the corresponding bit position(s).
OC1F–OC4F — Output Compare x Flag
Set each time the counter matches output compare x value
I4/O5F — Input Capture 4/Output Compare 5 Flag
Set by IC4 or OC5, depending on the function enabled by I4/O5 bit in PACTL
IC1F–IC3F — Input Capture x Flag
Set each time a selected active edge is detected on the ICx input line
Address: $1022
Bit 7654321Bit 0
Read: OC1I OC2I OC3I OC4I I4/O5I IC1I IC2I IC3I
Write:
Reset:00000000
Figure 9-17. Timer Interrupt Mask 1 Register (TMSK1)
Address: $1023
Bit 7654321Bit 0
Read: OC1F OC2F OC3F OC4F I4/O5F IC1F IC2F IC3F
Write:
Reset:00000000
Figure 9-18. Timer Interrupt Flag 1 Register (TFLG1)
Output Compare
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 139
9.4.9 Timer Interrupt Mask 2 Register
Use this 8-bit register to enable or inhibit timer overflow and real-time interrupts. The timer prescaler
control bits are included in this register.
TOI — Timer Overflow Interrupt Enable Bit
0 = TOF interrupts disabled
1 = Interrupt requested when TOF is set to 1
RTII — Real-Time Interrupt Enable Bit
Refer to 9.5 Real-Time Interrupt (RTI).
PAOVI — Pulse Accumulator Overflow Interrupt Enable Bit
Refer to 9.7.3 Pulse Accumulator Status and Interrupt Bits.
PAII — Pulse Accumulator Input Edge Interrupt Enable Bit
Refer to 9.7.3 Pulse Accumulator Status and Interrupt Bits.
Bits [3:2] — Unimplemented
Always read 0
PR[1:0] — Timer Prescaler Select Bits
These bits are used to select the prescaler divide-by ratio. In normal modes, PR[1:0] can be written
only once, and the write must be within 64 cycles after reset. Refer to Table 9-1 and Table 9-4 for
specific timing values.
NOTE
Bits in TMSK2 correspond bit for bit with flag bits in TFLG2. Bits in TMSK2
enable the corresponding interrupt sources.
Address: $1024
Bit 7654321Bit 0
Read:
TOI RTII PAOVI PAII PR1 PR0
Write:
Reset:00000000
= Unimplemented
Figure 9-19. Timer Interrupt Mask 2 Register (TMSK2)
Table 9-4. Timer Prescale
PR[1:0] Prescaler
0 0 1
0 1 4
1 0 8
1 1 16
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
140 Freescale Semiconductor
9.4.10 Timer Interrupt Flag Register 2
Bits in this register indicate when certain timer system events have occurred. Coupled with the four
high-order bits of TMSK2, the bits of TFLG2 allow the timer subsystem to operate in either a polled or
interrupt driven system. Each bit of TFLG2 corresponds to a bit in TMSK2 in the same position.
Clear flags by writing a 1 to the corresponding bit position(s).
TOF — Timer Overflow Interrupt Flag
Set when TCNT changes from $FFFF to $0000
RTIF — Real-Time (Periodic) Interrupt Flag
Refer to 9.5 Real-Time Interrupt (RTI).
PAOVF — Pulse Accumulator Overflow Interrupt Flag
Refer to 9.7 Pulse Accumulator.
PAIF — Pulse Accumulator Input Edge Interrupt Flag
Refer to 9.7 Pulse Accumulator.
Bits [3:0] — Unimplemented
Always read 0
9.5 Real-Time Interrupt (RTI)
The real-time interrupt (RTI) feature, used to generate hardware interrupts at a fixed periodic rate, is
controlled and configured by two bits (RTR1 and RTR0) in the pulse accumulator control (PACTL)
register. The RTII bit in the TMSK2 register enables the interrupt capability. The four different rates
available are a product of the MCU oscillator frequency and the value of bits RTR[1:0]. Refer to Table 9-5,
which shows the periodic real-time interrupt rates.
The clock source for the RTI function is a free-running clock that cannot be stopped or interrupted except
by reset. This clock causes the time between successive RTI timeouts to be a constant that is
Address: $1025
Bit 7654321Bit 0
Read:
TOF RTIF PAOVF PAIF
Write:
Reset:00000000
= Unimplemented
Figure 9-20. Timer Interrupt Flag 2 Register (TFLG2)
Table 9-5. RTI Rates
RTR[1:0] E = 3 MHz E = 2 MHz E = 1 MHz E = X MHz
0 0 2.731 ms 4.096 ms 8.192 ms (E/213)
0 1 5.461 ms 8.192 ms 16.384 ms (E/214)
1 0 10.923 ms 16.384 ms 32.768 ms (E/215)
1 1 21.845 ms 32.768 ms 65.536 ms (E/216)
Real-Time Interrupt (RTI)
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 141
independent of the software latencies associated with flag clearing and service. For this reason, an RTI
period starts from the previous timeout, not from when RTIF is cleared.
Every timeout causes the RTIF bit in TFLG2 to be set, and if RTII is set, an interrupt request is generated.
After reset, one entire RTI period elapses before the RTIF is set for the first time. Refer to the 9.4.9 Timer
Interrupt Mask 2 Register, 9.5.2 Timer Interrupt Flag Register 2, and 9.5.3 Pulse Accumulator Control
Register.
9.5.1 Timer Interrupt Mask Register 2
This register contains the real-time interrupt enable bits.
TOI — Timer Overflow Interrupt Enable Bit
0 = TOF interrupts disabled
1 = Interrupt requested when TOF is set to 1
RTII — Real-Time Interrupt Enable Bit
0 = RTIF interrupts disabled
1 = Interrupt requested when RTIF set to 1
PAOVI — Pulse Accumulator Overflow Interrupt Enable Bit
Refer to 9.7 Pulse Accumulator.
PAII — Pulse Accumulator Input Edge Bit
Refer to 9.7 Pulse Accumulator.
Bits [3:2] — Unimplemented
Always read 0
PR[1:0] — Timer Prescaler Select Bits
Refer to Table 9-4.
NOTE
Bits in TMSK2 correspond bit for bit with flag bits in TFLG2. Bits in TMSK2
enable the corresponding interrupt sources.
Address: $1024
Bit 7654321Bit 0
Read:
TOI RTI PAOVI PAII PR1 PR0
Write:
Reset:00000000
= Unimplemented
Figure 9-21. Timer Interrupt Mask 2 Register (TMSK2)
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
142 Freescale Semiconductor
9.5.2 Timer Interrupt Flag Register 2
Bits of this register indicate the occurrence of timer system events. Coupled with the four high-order bits
of TMSK2, the bits of TFLG2 allow the timer subsystem to operate in either a polled or interrupt driven
system. Each bit of TFLG2 corresponds to a bit in TMSK2 in the same position.
Clear flags by writing a 1 to the corresponding bit position(s).
TOF — Timer Overflow Interrupt Flag
Set when TCNT changes from $FFFF to $0000
RTIF — Real-Time Interrupt Flag
The RTIF status bit is automatically set to 1 at the end of every RTI period. To clear RTIF, write a byte
to TFLG2 with bit 6 set.
PAOVF — Pulse Accumulator Overflow Interrupt Flag
Refer to 9.7 Pulse Accumulator.
PAIF — Pulse Accumulator Input Edge Interrupt Flag
Refer to 9.7 Pulse Accumulator.
Bits [3:0] — Unimplemented
Always read 0
9.5.3 Pulse Accumulator Control Register
Bits RTR[1:0] of this register select the rate for the RTI system. The remaining bits control the pulse
accumulator and IC4/OC5 functions.
DDRA7 — Data Direction for Port A Bit 7
Refer to Chapter 6 Parallel Input/Output (I/O) Ports.
PAEN — Pulse Accumulator System Enable Bit
Refer to 9.7 Pulse Accumulator.
PAMOD — Pulse Accumulator Mode Bit
Refer to 9.7 Pulse Accumulator.
Address: $1025
Bit 7654321Bit 0
Read:
TOF RTIF PAOVF PAIF
Write:
Reset:00000000
= Unimplemented
Figure 9-22. Timer Interrupt Flag 2 Register (TFLG2)
Address: $1026
Bit 7654321Bit 0
Read:
DDRA7 PAEN PAMOD PEDGE DDRA3 I4/O5 RTR1 RTR0
Write:
Reset:00000000
Figure 9-23. Pulse Accumulator Control Register (PACTL)
Computer Operating Properly (COP) Watchdog Function
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 143
PEDGE — Pulse Accumulator Edge Control Bit
Refer to 9.7 Pulse Accumulator.
DDRA3 — Data Direction for Port A Bit 3
Refer to Chapter 6 Parallel Input/Output (I/O) Ports.
I4/O5 — Input Capture 4/Output Compare Bit
Refer to 9.7 Pulse Accumulator.
RTR[1:0] — RTI Interrupt Rate Select Bits
These two bits determine the rate at which the RTI system requests interrupts. The RTI system is
driven by an E divided by 213 rate clock that is compensated so it is independent of the timer prescaler.
These two control bits select an additional division factor. Refer to Table 9-5.
9.6 Computer Operating Properly (COP) Watchdog Function
The clocking chain for the COP function, tapped off of the main timer divider chain, is only superficially
related to the main timer system. The CR[1:0] bits in the OPTION register and the NOCOP bit in the
CONFIG register determine the status of the COP function. One additional register, COPRST, is used to
arm and clear the COP watchdog reset system. Refer to Chapter 5 Resets and Interrupts for a more
detailed discussion of the COP function.
9.7 Pulse Accumulator
The M68HC11 Family of MCUs has an 8-bit counter that can be configured to operate either as a simple
event counter or for gated time accumulation, depending on the state of the PAMOD bit in the PACTL
register. Refer to the pulse accumulator block diagram, Figure 9-24. In the event counting mode, the 8-bit
counter is clocked to increasing values by an external pin. The maximum clocking rate for the external
event counting mode is the E clock divided by two. In gated time accumulation mode, a free-running
E-clock divide-by-64 signal drives the 8-bit counter, but only while the external PAI pin is activated. Refer
to Table 9-6. The pulse accumulator counter can be read or written at any time.
Pulse accumulator control bits are also located within two timer registers, TMSK2 and TFLG2, as
described in the following paragraphs.
Table 9-6. Pulse Accumulator Timing
Crystal
Frequency E Clock Cycle Time E ÷ 64 PACNT
Overflow
4.0 MHz 1 MHz 1000 ns 64 µs 16.384 ms
8.0 MHz 2 MHz 500 ns 32 µs 8.192 ms
12.0 MHz 3 MHz 333 ns 21.33 µs 5.461 ms
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
144 Freescale Semiconductor
Figure 9-24. Pulse Accumulator
PEDGE
PAMOD
PAEN
PACTL CONTROL
INTERNAL
DATA BUS
PACNT 8-BIT COUNTER
PA7/
PAI/
OC1
INTERRUPT
REQUESTS
PAIF
PAOVF
TFLG2 INTERRUPT STATUS
PAOVI
PAII
PAOVF
PAOVI
PAIF
PAII
TMSK2 INT ENABLES
1
2
OVERFLOW
ENABLE
DISABLE
FLAG SETTING
CLOCK
PAI EDGE
PAEN
PAEN
2:1
MUX
OUTPUT
BUFFER
INPUT BUFFER
AND
EDGE DETECTOR
FROM
MAIN TIMER
OC1
DATA
BUS
MCU PIN
E ÷ 64 CLOCK
FROM MAIN TIMER
FROM
DDRA7
Pulse Accumulator
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 145
9.7.1 Pulse Accumulator Control Register
Four of this register’s bits control an 8-bit pulse accumulator system. Another bit enables either the OC5
function or the IC4 function, while two other bits select the rate for the real-time interrupt system.
DDRA7 — Data Direction for Port A Bit 7
Refer to Chapter 6 Parallel Input/Output (I/O) Ports.
PAEN — Pulse Accumulator System Enable Bit
0 = Pulse accumulator disabled
1 = Pulse accumulator enabled
PAMOD — Pulse Accumulator Mode Bit
0 = Event counter
1 = Gated time accumulation
PEDGE — Pulse Accumulator Edge Control Bit
This bit has different meanings depending on the state of the PAMOD bit, as shown in Table 9-7.
DDRA3 — Data Direction for Port A Bit 3
Refer to Chapter 6 Parallel Input/Output (I/O) Ports.
I4/O5 — Input Capture 4/Output Compare 5 Bit
0 = Output compare 5 function enable (no IC4)
1 = Input capture 4 function enable (no OC5)
RTR[1:0] — RTI Interrupt Rate Select Bits
Refer to 9.5 Real-Time Interrupt (RTI).
Address: $1026
Bit 7654321Bit 0
Read:
DDRA7 PAEN PAMOD PEDGE DDRA3 I4/O5 RTR1 RTR0
Write:
Reset:00000000
Figure 9-25. Pulse Accumulator Control Register (PACTL)
Table 9-7. Pulse Accumulator Edge Control
PAMOD PEDGE Action on Clock
0 0 PAI falling edge increments the counter.
0 1 PAI rising edge increments the counter.
1 0 A 0 on PAI inhibits counting.
1 1 A 1 on PAI inhibits counting.
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
146 Freescale Semiconductor
9.7.2 Pulse Accumulator Count Register
This 8-bit read/write register contains the count of external input events at the PAI input or the
accumulated count. The PACNT is readable even if PAI is not active in gated time accumulation mode.
The counter is not affected by reset and can be read or written at any time. Counting is synchronized to
the internal PH2 clock so that incrementing and reading occur during opposite half cycles.
9.7.3 Pulse Accumulator Status and Interrupt Bits
The pulse accumulator control bits, PAOVI and PAII, PAOVF and PAIF, are located within timer registers
TMSK2 and TFLG2.
PAOVI and PAOVF — Pulse Accumulator Interrupt Enable and Overflow Flag
The PAOVF status bit is set each time the pulse accumulator count rolls over from $FF to $00. To clear
this status bit, write a 1 in the corresponding data bit position (bit 5) of the TFLG2 register. The PAOVI
control bit allows configuring the pulse accumulator overflow for polled or interrupt-driven operation
and does not affect the state of PAOVF. When PAOVI is 0, pulse accumulator overflow interrupts are
inhibited, and the system operates in a polled mode, which requires that PAOVF be polled by user
software to determine when an overflow has occurred. When the PAOVI control bit is set, a hardware
interrupt request is generated each time PAOVF is set. Before leaving the interrupt service routine,
software must clear PAOVF by writing to the TFLG2 register.
Address: $1027
Bit 7654321Bit 0
Read: Bit 7 Bit 6 Bit 5 Bit 4 Bit 3 Bit 2 Bit 1 Bit 0
Write:
Reset: Indeterminate after reset
Figure 9-26. Pulse Accumulator Count Register (PACNT)
Address: $1024
Bit 7654321Bit 0
Read:
TOI RTII PAOVI PAII PR1 PR0
Write:
Reset:00000000
= Unimplemented
Figure 9-27. Timer Interrupt Mask 2 Register (TMSK2)
Address: $1025
Bit 7654321Bit 0
Read:
TOF RTIF PAOVF PAIF
Write:
Reset:00000000
= Unimplemented
Figure 9-28. Timer Interrupt Flag 2 Register (TFLG2)
Pulse Accumulator
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 147
PAII and PAIF — Pulse Accumulator Input Edge Interrupt Enable Bit and Flag
The PAIF status bit is automatically set each time a selected edge is detected at the PA7/PAI/OC1 pin.
To clear this status bit, write to the TFLG2 register with a 1 in the corresponding data bit position (bit
4). The PAII control bit allows configuring the pulse accumulator input edge detect for polled or
interrupt-driven operation but does not affect setting or clearing the PAIF bit. When PAII is 0, pulse
accumulator input interrupts are inhibited, and the system operates in a polled mode. In this mode, the
PAIF bit must be polled by user software to determine when an edge has occurred. When the PAII
control bit is set, a hardware interrupt request is generated each time PAIF is set. Before leaving the
interrupt service routine, software must clear PAIF by writing to the TFLG2 register.
Timing Systems
M68HC11E Family Data Sheet, Rev. 5.1
148 Freescale Semiconductor
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 149
Chapter 10
Electrical Characteristics
10.1 Introduction
This section contains electrical specifications for the M68HC11 E-series devices.
10.2 Maximum Ratings for Standard and Extended Voltage Devices
Maximum ratings are the extreme limits to which the microcontroller unit (MCU) can be exposed without
permanently damaging it.
NOTE
This device is not guaranteed to operate properly at the maximum ratings.
Refer to 10.5 DC Electrical Characteristics, 10.6 Supply Currents and
Power Dissipation, 10.7 MC68L11E9/E20 DC Electrical Characteristics,
and 10.8 MC68L11E9/E20 Supply Currents and Power Dissipation for
guaranteed operating conditions.
NOTE
This device contains circuitry to protect the inputs against damage due to
high static voltages or electric fields; however, it is advised that normal
precautions be taken to avoid application of any voltage higher than
maximum-rated voltages to this high-impedance circuit. For proper
operation, it is recommended that VIn and VOut be constrained to the range
VSS ≤ (VIn or VOut) ≤ VDD. Reliability of operation is enhanced if unused
inputs are connected to an appropriate logic voltage level (for example,
either VSS or VDD).
Rating Symbol Value Unit
Supply voltage VDD –0.3 to +7.0 V
Input voltage VIn –0.3 to +7.0 V
Current drain per pin(1) excluding VDD, VSS, AVDD, VRH, VRL, and
XIRQ/VPPE
1. One pin at a time, observing maximum power dissipation limits
ID25 mA
Storage temperature TSTG –55 to +150 °C
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
150 Freescale Semiconductor
10.3 Functional Operating Range
10.4 Thermal Characteristics
Rating Symbol Value Unit
Operating temperature range
MC68HC(7)11Ex
MC68HC(7)11ExC
MC68HC(7)11ExV
MC68HC(7)11ExM
MC68HC811E2
MC68HC811E2C
MC68HC811E2V
MC68HC811E2M
MC68L11Ex
TA
TL to TH
0 to +70
–40 to +85
–40 to +105
–40 to +125
0 to +70
–40 to +85
–40 to +105
–40 to +125
–20 to +70
°C
Operating voltage range VDD 5.0 ± 10% V
Characteristic Symbol Value Unit
Average junction temperature TJTA + (PD × ΘJA)°C
Ambient temperature TAUser-determined °C
Package thermal resistance (junction-to-ambient)
48-pin plastic DIP (MC68HC811E2 only)
56-pin plastic SDIP
52-pin plastic leaded chip carrier
52-pin plastic thin quad flat pack (TQFP)
64-pin quad flat pack
ΘJA
50
50
50
85
85
°C/W
Total power dissipation(1)
1. This is an approximate value, neglecting PI/O.
PD
PINT + PI/O
K / TJ + 273°CW
Device internal power dissipation PINT IDD × VDD W
I/O pin power dissipation(2)
2. For most applications, PI/O ≤ PINT and can be neglected.
PI/O User-determined W
A constant(3)
3. K is a constant pertaining to the device. Solve for K with a known TA and a measured PD (at equilibrium). Use this value
of K to solve for PD and TJ iteratively for any value of TA.
KPD × (TA + 273°C)
+ ΘJA × PD2 W/°C
DC Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 151
10.5 DC Electrical Characteristics
Characteristics(1)
1. VDD = 5.0 Vdc ± 10%, VSS = 0 Vdc, TA = TL to TH, unless otherwise noted
Symbol Min Max Unit
Output voltage(2)
ILoad = ±±10.0 µA
All outputs except XTAL
All outputs except XTAL, RESET, and MODA
2. VOH specification for RESET and MODA is not applicable because they are open-drain pins. VOH specification not appli-
cable to ports C and D in wired-OR mode.
VOL, VOH —
VDD –0.1
0.1
—
V
Output high voltage(2)
ILoad = –0.8 mA, VDD = 4.5 V
All outputs except XTAL, RESET
, and MODA
VOH VDD –0.8 —V
Output low voltage
ILoad = 1.6 mA
All outputs except XTAL
VOL —0.4 V
Input high voltage
All inputs except RESET
RESET
VIH
0.7 × VDD
0.8 × VDD
VDD + 0.3
VDD + 0.3 V
Input low voltage, all inputs VIL VSS –0.3 0.2 × VDD V
I/O ports, 3-state leakage
VIn = VIH or VIL
PA7, PA3, PC[7:0], PD[5:0], AS/STRA,
MODA/LIR, RESET
IOZ —±10 µA
Input leakage current(3)
VIn = VDD or VSS
PA[2:0], IRQ, XIRQ
MODB/VSTBY (XIRQ on EPROM-based devices)
3. Refer to 10.13 Analog-to-Digital Converter Characteristics and 10.14 MC68L11E9/E20 Analog-to-Digital Converter Char-
acteristics for leakage current for port E.
IIn —
—
±1
±10
µA
RAM standby voltage, power down VSB 4.0 VDD V
RAM standby current, power down ISB —10µA
Input capacitance
PA[2:0], PE[7:0], IRQ, XIRQ, EXTAL
PA7, PA3, PC[7:0], PD[5:0], AS/STRA, MODA/LIR, RESET
CIn —
—
8
12
pF
Output load capacitance
All outputs except PD[4:1]
PD[4:1]
CL—
—
90
100
pF
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
152 Freescale Semiconductor
10.6 Supply Currents and Power Dissipation
Characteristics(1)
1. VDD = 5.0 Vdc ± 10%, VSS = 0 Vdc, TA = TL to TH, unless otherwise noted
Symbol Min Max Unit
Run maximum total supply current(2)
Single-chip mode2 MHz
3 MHz
Expanded multiplexed mode2 MHz
3 MHz
2. EXTAL is driven with a square wave, and
tCYC= 500 ns for 2 MHz rating
tCYC= 333 ns for 3 MHz rating
VIL ≤ 0.2 V
VIH ≥ VDD – 0.2 V
no dc loads
IDD
—
—
—
—
15
27
27
35
mA
Wait maximum total supply current(2)
(all peripheral functions shut down)
Single-chip mode2 MHz
3 MHz
Expanded multiplexed mode2 MHz
3 MHz
WIDD
—
—
—
—
6
15
10
20
mA
Stop maximum total supply current(2)
Single-chip mode, no clocks–40°C to +85°C
> +85°C to +105°C
> +105°C to +125°C
SIDD —
—
—
25
50
100
µA
Maximum power dissipation
Single-chip mode2 MHz
3 MHz
Expanded multiplexed mode2 MHz
3 MHz
PD
—
—
—
—
85
150
150
195
mW
MC68L11E9/E20 DC Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 153
10.7 MC68L11E9/E20 DC Electrical Characteristics
Characteristics(1)
1. VDD = 3.0 Vdc to 5.5 Vdc, VSS = 0 Vdc, TA = TL to TH, unless otherwise noted
Symbol Min Max Unit
Output voltage(2)
ILoad = ±±10.0 µA
All outputs except XTAL
All outputs except XTAL, RESET, and MODA
2. VOH specification for RESET and MODA is not applicable because they are open-drain pins. VOH specification not appli-
cable to ports C and D in wired-OR mode.
V OL, VOH —
VDD –0.1
0.1
—
V
Output high voltage(2)
ILoad = –0.5 mA, VDD = 3.0 V
ILoad = –0.8 mA, VDD = 4.5 V
All outputs except XTAL, RESET, and MODA
VOH VDD –0.8 —V
Output low voltage
ILoad = 1.6 mA, VDD = 5.0 V
ILoad = 1.0 mA, VDD = 3.0 V
All outputs except XTAL
VOL —0.4 V
Input high voltage
All inputs except RESET
RESET
VIH 0.7 × VDD
0.8 × VDD
VDD + 0.3
VDD + 0.3
V
Input low voltage, all inputs VIL VSS –0.3 0.2 × VDD V
I/O ports, 3-state leakage
VIn = VIH or VIL
PA7, PA3, PC[7:0], PD[5:0], AS/STRA,
MODA/LIR, RESET
IOZ —±10 µA
Input leakage current(3)
VIn = VDD or VSS
PA[2:0], IRQ, XIRQ
MODB/VSTBY (XIRQ on EPROM-based devices)
3. Refer to 10.13 Analog-to-Digital Converter Characteristics and 10.14 MC68L11E9/E20 Analog-to-Digital Converter Char-
acteristics for leakage current for port E.
IIn —
—
±1
±10
µA
RAM standby voltage, power down VSB 2.0 VDD V
RAM standby current, power down ISB —10µA
Input capacitance
PA[2:0], PE[7:0], IRQ, XIRQ, EXTAL
PA7, PA3, PC[7:0], PD[5:0], AS/STRA, MODA/LIR, RESET
l—
—
8
12
pF
Output load capacitance
All outputs except PD[4:1]
PD[4:1]
CL—
—
90
100
pF
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
154 Freescale Semiconductor
10.8 MC68L11E9/E20 Supply Currents and Power Dissipation
Characteristic(1)
1. VDD = 3.0 Vdc to 5.5 Vdc, VSS = 0 Vdc, TA = TL to TH, unless otherwise noted
Symbol 1 MHz 2 MHz Unit
Run maximum total supply current(2)
Single-chip mode
VDD = 5.5 V
VDD = 3.0 V
Expanded multiplexed mode
VDD = 5.5 V
VDD = 5.5 V
2. EXTAL is driven with a square wave, and
tCYC= 500 ns for 2 MHz rating
tCYC= 333 ns for 3 MHz rating
VIL ≤ 0.2 V
VIH ≥ VDD – 0.2 V
no dc loads
IDD
8
4
14
7
15
8
27
14
mA
Wait maximum total supply current(2)
(all peripheral functions shut down)
Single-chip mode
VDD = 5.5 V
VDD = 3.0 V
Expanded multiplexed mode
VDD = 5.5 V
VDD = 3.0 V
WIDD 3
1.5
5
2.5
6
3
10
5
mA
Stop maximum total supply current(2)
Single-chip mode, no clocks
VDD = 5.5 V
VDD = 3.0 V
SIDD 50
25
50
25
µA
Maximum power dissipation
Single-chip mode
2 MHz
3 MHz
Expanded multiplexed mode
2 MHz
3 MHz
PD
44
12
77
21
85
24
150
42
mW
MC68L11E9/E20 Supply Currents and Power Dissipation
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 155
Figure 10-1. Test Methods
Notes:
1. Full test loads are applied during all dc electrical tests and ac timing measurements.
2. During ac timing measurements, inputs are driven to 0.4 volts and VDD – 0.8 volts while timing
CLOCKS,
STROBES
INPUTS
VDD – 0.8 Volts
0.4 Volts
VDD
~
NOMINAL TIMING
NOM
20% of VDD
70% of VDD
VDD – 0.8 VOLTS
0.4 VOLTS
VSS
~
VDD~
NOM
OUTPUTS
0.4 VOLTS
DC TESTING
CLOCKS,
STROBES
INPUTS
20% of VDD
70% of VDD
VSS~
VDD~
SPEC TIMING
VDD – 0.8 VOLTS
20% of VDD
70% of VDD
0.4 VOLTS
VSS~
VDD
~
SPEC
OUTPUTS
AC TESTING
(NOTE 2)
20% of VDD
70% of VDD
20% of VDD
VSS
~
SPEC
measurements are taken at 20% and 70% of VDD points.
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
156 Freescale Semiconductor
10.9 Control Timing
Characteristic(1) (2)
1. VDD = 5.0 Vdc ±10%, VSS = 0 Vdc, TA = TL to TH, all timing is shown with respect to 20% VDD and 70% VDD, unless oth-
erwise noted
2. RESET is recognized during the first clock cycle it is held low. Internal circuitry then drives the pin low for four clock cycles,
releases the pin, and samples the pin level two cycles later to determine the source of the interrupt. Refer to Chapter 5
Resets and Interrupts for further detail.
Symbol 1.0 MHz 2.0 MHz 3.0 MHz Unit
MinMaxMinMaxMinMax
Frequency of operation fodc 1.0 dc 2.0 dc 3.0 MHz
E-clock period tCYC 100
0— 500 — 333 — ns
Crystal frequency fXTAL —4.0—8.0—12.0MHz
External oscillator frequency 4 fodc 4.0 dc 8.0 dc 12.0 MHz
Processor control setup time
tPCSU = 1/4 tCYC+ 50 ns tPCSU 300 — 175 — 133 — ns
Reset input pulse width
To guarantee external reset vector
Minimum input time (can be pre-empted by internal reset)
PWRSTL 8
1
—
—
8
1
—
—
8
1
—
—
tCYC
Mode programming setup time tMPS 2—2—2—
tCYC
Mode programming hold time tMPH 10 — 10 — 10 — ns
Interrupt pulse width, IRQ edge-sensitive mode
PWIRQ = tCYC + 20 ns PWIRQ 102
0— 520 — 353 — ns
Wait recovery startup time tWRS —4—4—4tCYC
Timer pulse width input capture pulse accumulator input
PWTIM = tCYC + 20 ns PWTIM 102
0— 520 — 353 — ns
MC68L11E9/E20 Control Timing
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 157
10.10 MC68L11E9/E20 Control Timing
Figure 10-2. Timer Inputs
Characteristic(1) (2)
1. VDD = 3.0 Vdc to 5.5 Vdc, VSS = 0 Vdc, TA = TL to TH, all timing is shown with respect to 20% VDD and 70% VDD, unless
otherwise noted
2. RESET is recognized during the first clock cycle it is held low. Internal circuitry then drives the pin low for four clock cycles,
releases the pin, and samples the pin level two cycles later to determine the source of the interrupt. Refer to Chapter 5
Resets and Interrupts for further detail.
Symbol 1.0 MHz 2.0 MHz Unit
Min Max Min Max
Frequency of operation fodc 1.0 dc 2.0 MHz
E-clock period tCYC 1000 — 500 — ns
Crystal frequency fXTAL —4.0—8.0MHz
External oscillator frequency 4 fodc 4.0 dc 8.0 MHz
Processor control setup time
tPCSU = 1/4 tCYC+ 75 ns tPCSU 325 — 200 — ns
Reset input pulse width
To guarantee external reset vector
Minimum input time (can be pre-empted by internal reset)
PWRSTL 8
1
—
—
8
1
—
—
tCYC
Mode programming setup time tMPS 2—2—tCYC
Mode programming hold time tMPH 10 — 10 — ns
Interrupt pulse width, IRQ edge-sensitive mode
PWIRQ = tCYC + 20 ns PWIRQ 1020 — 520 — ns
Wait recovery startup time tWRS —4—4tCYC
Timer pulse width input capture pulse accumulator input
PWTIM = tCYC + 20 ns PWTIM 1020 — 520 — ns
Notes:
1. Rising edge sensitive input
2. Falling edge sensitive input
3. Maximum pulse accumulator clocking rate is E-clock frequency divided by 2.
PA7(2) (3)
PA7(1) (3)
PA[2:0](2)
PA[2:0](1)
PWTIM
M68HC11E Family Data Sheet, Rev. 5.1
158 Freescale Semiconductor
Electrical Characteristics
Figure 10-3. POR External Reset Timing Diagram
tPCSU
ADDRESS
MODA, MODB
E
EXTAL
VDD
RESET
4064 tCYC
FFFEFFFEFFFE NEW
PC
FFFE FFFF FFFEFFFEFFFE NEW
PC
FFFE FFFFFFFE
tMPH
PWRSTL
tMPS
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 159
MC68L11E9/E20 Control Timing
Figure 10-4. STOP Recovery Timing Diagram
PWIRQ
tSTOPDELAY
3
IRQ1
IRQ
or XIRQ
E
SP – 8SP – 8 FFF2
(FFF4)
NEW
PC
STOP
ADDR
STOP
ADDR + 1
ADDRESS4STOP
ADDR
STOP
ADDR + 1
STOP
ADDR + 1
STOP
ADDR + 1
STOP
ADDR + 2 SP…SP–7 FFF3
(FFF5)
OPCODE
Resume program with instruction which follows the STOP instruction.
Notes:
1. Edge Sensitive IRQ pin (IRQE bit = 1)
2. Level sensitive IRQ pin (IRQE bit = 0)
4. XIRQ with X bit in CCR = 1.
5. IRQ or (XIRQ with X bit in CCR = 0).
INTERNAL
ADDRESS5
CLOCKS
3. tSTOPDELAY = 4064 tCYC if DLY bit = 1 or 4 tCYC if DLY = 0.
M68HC11E Family Data Sheet, Rev. 5.1
160 Freescale Semiconductor
Electrical Characteristics
Figure 10-5. WAIT Recovery from Interrupt Timing Diagram
tPCSU
PCL PCH, YL, YH, XL, XH, A, B, CCR
STACK REGISTERS
E
R/W
ADDRESS WAIT
ADDR
WAIT
ADDR + 1
IRQ, XIRQ,
OR INTERNAL
INTERRUPTS
Note: RESET also causes recovery from WAIT.
SP SP – 1 SP – 2…SP – 8 SP – 8 SP – 8…SP – 8 SP – 8 SP – 8 SP – 8 VECTOR
ADDR
VECTOR
ADDR + 1
NEW
PC
tWRS
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 161
MC68L11E9/E20 Control Timing
Figure 10-6. Interrupt Timing Diagram
E
PWIRQ
SP – 8SP – 8ADDRESS NEW
PC
NEXT
OPCODE
NEXT
OP + 1
IRQ 1
VECTOR
ADDR
SP – 7
tPCSU
IRQ 2, XIRQ,
OR INTERNAL
INTERRUPT
SP SP – 1 SP – 2 SP – 3 SP – 4 SP – 5 SP – 6 VECTOR
ADDR + 1
OP
CODE – –
Notes:
1. Edge sensitive IRQ pin (IRQE bit = 1)
2. Level sensitive IRQ pin (IRQE bit = 0)
DATA PCL PCH IYL IYH IXL IXH B A CCR – – VECT
MSB
VECT
LSB
OP
CODE
R/W
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
162 Freescale Semiconductor
10.11 Peripheral Port Timing
Characteristic(1) (2)
1. VDD = 5.0 Vdc ± 10%, VSS = 0 Vdc, TA = TL to TH, all timing is shown with respect to 20% VDD and 70% VDD, unless
otherwise noted
2. Ports C and D timing is valid for active drive. (CWOM and DWOM bits are not set in PIOC and SPCR registers, respec-
tively.)
Symbol 1.0 MHz 2.0 MHz 3.0 MHz Unit
Min Max Min Max Min Max
Frequency of operation
E-clock frequency fodc 1.0 dc 2.0 dc 3.0 MHz
E-clock period tCYC 1000 — 500 — 333 — ns
Peripheral data setup time
MCU read of ports A, C, D, and E tPDSU 100 — 100 — 100 — ns
Peripheral data hold time
MCU read of ports A, C, D, and E tPDH 50 — 50 — 50 — ns
Delay time, peripheral data write
tPWD = 1/4 tCYC+ 100 ns
MCU writes to port A
MCU writes to ports B, C, and D
tPWD —
—
200
350
—
—
200
225
—
—
200
183
ns
Port C input data setup time tIS 60 — 60 — 60 — ns
Port C input data hold time tIH 100 — 100 — 100 — ns
Delay time, E fall to STRB
tDEB = 1/4 tCYC+ 100 ns tDEB — 350 — 225 — 183 ns
Setup time, STRA asserted to E fall(3)
3. If this setup time is met, STRB acknowledges in the next cycle. If it is not met, the response may be delayed one more cycle.
tAES 0—0—0—ns
Delay time, STRA asserted to port C data output valid tPCD — 100 — 100 — 100 ns
Hold time, STRA negated to port C data tPCH 10 — 10 — 10 — ns
3-state hold time tPCZ — 150 — 150 — 150 ns
MC68L11E9/E20 Peripheral Port Timing
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 163
10.12 MC68L11E9/E20 Peripheral Port Timing
Figure 10-7. Port Read Timing Diagram
Characteristic(1) (2)
1. VDD = 3.0 Vdc to 5.5 Vdc, VSS = 0 Vdc, TA = TL to TH, all timing is shown with respect to 20% VDD and 70% VDD, unless
otherwise noted
2. Ports C and D timing is valid for active drive. (CWOM and DWOM bits are not set in PIOC and SPCR registers, respec-
tively.)
Symbol 1.0 MHz 2.0 MHz Unit
Min Max Min Max
Frequency of operation
E-clock frequency fodc 1.0 dc 2.0 MHz
E-clock period tCYC 1000 — 500 — ns
Peripheral data setup time
MCU read of ports A, C, D, and E tPDSU 100 — 100 — ns
Peripheral data hold time
MCU read of ports A, C, D, and E tPDH 50 — 50 — ns
Delay time, peripheral data write
tPWD = 1/4 tCYC+ 150 ns
MCU writes to port A
MCU writes to ports B, C, and D
tPWD —
—
250
400
—
—
250
275
ns
Port C input data setup time tIS 60 — 60 — ns
Port C input data hold time tIH 100 — 100 — ns
Delay time, E fall to STRB
tDEB = 1/4 tCYC+ 150 ns tDEB — 400 — 275 ns
Setup time, STRA asserted to E fall(3)
3. If this setup time is met, STRB acknowledges in the next cycle. If it is not met, the response may be delayed one more cycle.
tAES 0—0—ns
Delay time, STRA asserted to port C data output valid tPCD — 100 — 100 ns
Hold time, STRA negated to port C data tPCH 10 — 10 — ns
3-state hold time tPCZ — 150 — 150 ns
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
164 Freescale Semiconductor
Figure 10-8. Port Write Timing Diagram
Figure 10-9. Simple Input Strobe Timing Diagram
Figure 10-10. Simple Output Strobe Timing Diagram
Figure 10-11. Port C Input Handshake Timing Diagram
t
PWD
E
MCU WRITE TO PORT B
PREVIOUS PORT DATA NEW DATA VALI
D
STRB (OUT)
PORT B
t
DEB
MCU WRITE TO PORT B
tPWD
tDEB
NEW DATA VALID
PREVIOUS PORT DATA
E
PORT B
STRB (OUT)
PORT C INPUT HNDSHK TIM
E
PORT C (IN)
t
DEB
STRB (OUT)
READ PORTCL1
STRA (IN)
t
DEB
"READY"
NOTES:
1. After reading PIOC with STAF set
2. Figure shows rising edge STRA (EGA = 1) and high tr ue STRB (INVB = 1).
t
AES
t
IS
t
IH
E
STRB (0UT)
STRA (IN)
PORT C (IN)
Notes:
1. After reading PIOC with STAF set
2. Figure shows rising edge STRA (EGA = 1) and high true STRB (INVB = 1).
“READY”
READ PORTCL(1)
tDEB
tAES
tIS tIH
tDEB
MC68L11E9/E20 Peripheral Port Timing
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 165
Figure 10-12. Port C Output Handshake Timing Diagram
Figure 10-13. 3-State Variation of Output Handshake Timing Diagram
(STRA Enables Output Buffer)
PORT C OUTPUT HNDS HK TIM
t
PWD
E
PREVIOUS PORT DATA NEW DATA VALI
D
STRB (OUT)
PORT C (OUT)
WRITE PORTCL1
"READY"
STRA (IN)
NOTES:
1. After reading PIOC with ST A F set
2. Figure shows rising edge S T RA (EGA = 1) and high true STR B (INVB = 1).
t
DEB
t
DEB
t
AES
E
PORT C (OUT)
STRB (IN)
STRA (IN)
Notes:
1. After reading PIOC with STAF set
2. Figure shows rising edge STRA (EGA = 1) and high true STRB (INVB = 1).
“READY”
WRITE PORTCL(1)
tDEB
tAES
tPWD
tDEB
PREVIOUS PORT DATA NEW DATA VALID
E
t
DEB
PORT C (OUT)
(DDR = 1)
READ PORTCL1
STRB (OUT)
t
PWD
"READY"
NOTES:
1. After reading PIOC with STAF set
2. Figure shows rising edge STRA (EGA = 1) and high true STRB (INVB = 1).
t
AES
OLD DATA NEW DATA VALI
D
PORT C (OUT)
(DDR = 0)
STRA (IN)
a) STRA ACTIVE BEFORE PORTCL WRITE
NEW DATA VALI
D
PORT C (OUT)
(DDR = 0)
STRA (IN)
b) STRA ACTIVE AFTER PORTCL WRITE
t
DEB
t
PCZ
t
PCH
t
PCZ
t
PCH
t
PCD
t
PCD
E
PORT C (OUT)
DDR = 1
STRB (OUT)
STRA (IN)
PORT C (OUT)
DDR = 0
STRA (IN)
PORT C (OUT)
DDR = 0
a) STRA ACTIVE BEFORE PORTCL WRITE
b) STRA ACTIVE AFTER PORTCL WRITE
READ PORTCL(1)
tPWD
tDEB tDEB
“READY”
t
AES
tPCD
tPCD tPCH
tPCZ
tPCH
tPCZ
OLD DATA NEW DATA VALID
NEW DATA VALID
Notes:
1. After reading PIOC with STAF set
2. Figure shows rising edge STRA (EGA = 1) and high true STRB (INVB = 1).
tPCH
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
166 Freescale Semiconductor
10.13 Analog-to-Digital Converter Characteristics
Characteristic(1)
1. VDD = 5.0 Vdc ±10%, VSS = 0 Vdc, TA = TL to TH, 750 kHz ≤ E ≤ 3.0 MHz, unless otherwise noted
Parameter(2)
2. Source impedances greater than 10 kΩ affect accuracy adversely because of input leakage.
Min Absolute 2.0 MHz 3.0 MHz Uni
t
Max Max
Resolution Number of bits resolved by A/D converter — 8 — — Bits
Non-linearity Maximum deviation from the ideal A/D transfer
characteristics ——±1/2 ±1LS
B
Zero error Difference between the output of an ideal and an
actual for 0 input voltage ——±1/2 ±1LS
B
Full scale error Difference between the output of an ideal and an
actual A/D for full-scale input voltage ——±1/2 ±1LS
B
Total unadjusted
error
Maximum sum of non-linearity, zero error, and
full-scale error ——±1/2 ±1/2 LS
B
Quantization
error Uncertainty because of converter resolution — — ±1/2 ±1/2 LS
B
Absolute
accuracy
Difference between the actual input voltage and
the full-scale weighted equivalent of the binary
output code, all error sources included
——±1±2LS
B
Conversion
range Analog input voltage range VRL —VRH VRH V
VRH Maximum analog reference voltage(3)
3. Performance verified down to 2.5 V ∆VR, but accuracy is tested and guaranteed at ∆VR = 5 V ±10%.
VRL —VDD +0.1 VDD +0.1 V
VRL Minimum analog reference voltage(2) VSS –0.1 —VRH VRH V
∆VRMinimum difference between VRH and VRL(2) 3———V
Conversion
time
Total time to perform a single A/D conversion:
E clock
Internal RC oscillator
—
—
32
—
—
tCYC+32
—
tCYC+32
tCY
C
µs
Monotonicity Conversion result never decreases with an
increase in input voltage; has no missing codes — Guaranteed — — —
Zero input reading Conversion result when VIn = VRL 00 — — — Hex
Full scale
reading Conversion result when VIn = VRH — — FF FF Hex
Sample
acquisition
time
Analog input acquisition sampling time:
E clock
Internal RC oscillator
—
—
12
—
—
12
—
12
tCY
C
µs
Sample/hold
capacitance
Input capacitance during sample
PE[7:0] — 20 typical — — pF
Input leakage
Input leakage on A/D pins
PE[7:0]
VRL, VRH
—
—
—
—
400
1.0
400
1.0
nA
µA
MC68L11E9/E20 Analog-to-Digital Converter Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 167
10.14 MC68L11E9/E20 Analog-to-Digital Converter Characteristics
Characteristic(1)
1. VDD = 3.0 Vdc to 5.5 Vdc, VSS = 0 Vdc, TA = TL to TH, 750 kHz ≤ E ≤ 2.0 MHz, unless otherwise noted
Parameter(2)
2. Source impedances greater than 10 kΩ affect accuracy adversely because of input leakage.
Min Absolute Max Unit
Resolution Number of bits resolved by A/D converter — 8 — Bits
Non-linearity Maximum deviation from the ideal A/D transfer
characteristics ——±1LSB
Zero error Difference between the output of an ideal and an
actual for 0 input voltage ——±1LSB
Full scale error Difference between the output of an ideal and an
actual A/D for full-scale input voltage ——±1LSB
Total unadjusted
error
Maximum sum of non-linearity, zero error, and
full-scale error ——±1/2 LSB
Quantization error Uncertainty because of converter resolution — — ±1/2 LSB
Absolute accuracy
Difference between the actual input voltage and
the full-scale weighted equivalent of the binary
output code, all error sources included
——±2LSB
Conversion range Analog input voltage range VRL —VRH V
VRH Maximum analog reference voltage VRL —VDD + 0.1 V
VRL Minimum analog reference voltage VSS –0.1 —VRH V
∆VRMinimum difference between VRH and VRL 3.0 — — V
Conversion time
Total time to perform a single
analog-to-digital conversion:
E clock
Internal RC oscillator
—
—
32
—
—
tCYC+ 32
tCYC
µs
Monotonicity
Conversion result never decreases with an
increase in input voltage and has no missing
codes
— Guaranteed — —
Zero input reading Conversion result when VIn = VRL 00 — — Hex
Full scale reading Conversion result when VIn = VRH ——FFHex
Sample acquisition
time
Analog input acquisition sampling time:
E clock
Internal RC oscillator
—
—
12
—
—
12
tCYC
µs
Sample/hold
capacitance
Input capacitance during sample
PE[7:0] — 20 typical — pF
Input leakage
Input leakage on A/D pins
PE[7:0]
VRL, VRH
—
—
—
—
400
1.0
nA
µA
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
168 Freescale Semiconductor
10.15 Expansion Bus Timing Characteristics
Num Characteristic(1)
1. VDD = 5.0 Vdc ±10%, VSS = 0 Vdc, TA = TL to TH, all timing is shown with respect to 20% VDD and 70% VDD, unless oth-
erwise noted
Symbol 1.0 MHz 2.0 MHz 3.0 MHz Unit
Min Max Min Max Min Max
Frequency of operation (E-clock frequency) fodc 1.0 dc 2.0 dc 3.0 MHz
1 Cycle time tCYC 1000 — 500 — 333 — ns
2Pulse width, E low(2), PWEL = 1/2 tCYC–23 ns
2. Formula only for dc to 2 MHz
PWEL 477 — 227 — 146 — ns
3Pulse width, E high(2), PWEH = 1/2 tCYC–28 ns PWEH 472 — 222 — 141 — ns
4a E and AS rise time tr—20—20—20ns
4b E and AS fall time tf—20—20—15ns
9Address hold time(2) (3)a, tAH = 1/8 tCYC–29.5 ns
3. Input clocks with duty cycles other than 50% affect bus performance. Timing parameters affected by input clock duty cycle
are identified by (a) and (b). To recalculate the approximate bus timing values, substitute the following expressions in place
of 1/8 tCYCin the above formulas, where applicable:
(a) (1–dc) × 1/4 tCYC
(b) dc × 1/4 tCYC
Where:
dc is the decimal value of duty cycle percentage (high time)
tAH 95.5 — 33 — 26 — ns
12 Non-multiplexed address valid time to E rise
tAV = PWEL –(tASD + 80 ns)(2) (3)a tAV 281.5 — 94 — 54 — ns
17 Read data setup time tDSR 30 — 30 — 30 — ns
18 Read data hold time, max = tMAD tDHR 0 145.5 0 83 0 51 ns
19 Write data delay time, tDDW = 1/8 tCYC+ 65.5 ns(2) (3)a tDDW — 190.5 — 128 71 ns
21 Write data hold time, tDHW = 1/8 tCYC–29.5 ns(2) (3)a tDHW 95.5 — 33 — 26 — ns
22 Multiplexed address valid time to E rise
tAVM = PWEL –(tASD + 90 ns)(2) (3)a tAVM 271.5 — 84 — 54 — ns
24 Multiplexed address valid time to AS fall
tASL = PWASH –70 ns(2) tASL 151 — 26 — 13 — ns
25 Multiplexed address hold time
tAHL = 1/8 tCYC–29.5 ns(2) (3)b tAHL 95.5 — 33 — 31 — ns
26 Delay time, E to AS rise, tASD = 1/8 tCYC–9.5 ns(2) (3)a tASD 115.5 — 53 — 31 — ns
27 Pulse width, AS high, PWASH = 1/4 tCYC–29 ns(2) PWASH 221 — 96 — 63 — ns
28 Delay time, AS to E rise, tASED = 1/8 tCYC–9.5 ns(2) (3)b tASED 115.5 — 53 — 31 — ns
29 MPU address access time(3)a
tACCA = tCYC–(PWEL–tAVM) –tDSR–tf
tACCA 744.5 — 307 — 196 — ns
35 MPU access time, tACCE = PWEH –tDSR tACCE — 442 — 192 111 ns
36 Multiplexed address delay (Previous cycle MPU read)
tMAD = tASD + 30 ns(2) (3)a tMAD 145.5 — 83 — 51 — ns
MC68L11E9/E20 Expansion Bus Timing Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 169
10.16 MC68L11E9/E20 Expansion Bus Timing Characteristics
Num Characteristic(1)
1. VDD = 3.0 Vdc to 5.5 Vdc, VSS = 0 Vdc, TA = TL to TH, all timing is shown with respect to 20% VDD and 70% VDD, unless
otherwise noted
Symbol 1.0 MHz 2.0 MHz Unit
Min Max Min Max
Frequency of operation (E-clock frequency) fodc 1.0 dc 2.0 MHz
1Cycle time tCYC 1000 — 500 — ns
2Pulse width, E low, PWEL = 1/2 tCYC–25 ns PWEL 475 — 225 — ns
3Pulse width, E high, PWEH = 1/2 tCYC–30 ns PWEH 470 — 220 — ns
4a E and AS rise time tr— 25 — 25 ns
4b E and AS fall time tf— 25 — 25 ns
9Address hold time(2) (2)a, tAH = 1/8 tCYC–30 ns
2. Input clocks with duty cycles other than 50% affect bus performance. Timing parameters affected by input clock duty cycle
are identified by (a) and (b). To recalculate the approximate bus timing values, substitute the following expressions in place
of 1/8 tCYCin the above formulas, where applicable:
(a) (1–dc) × 1/4 tCYC
(b) dc × 1/4 tCYC
Where:
dc is the decimal value of duty cycle percentage (high time).
tAH 95 — 33 — ns
12 Non-multiplexed address valid time to E rise
tAV = PWEL –(tASD + 80 ns)(2)a tAV 275 — 88 — ns
17 Read data setup time tDSR 30 — 30 — ns
18 Read data hold time , max = tMAD tDHR 01500 88ns
19 Write data delay time, tDDW = 1/8 tCYC+ 70 ns(2)a tDDW — 195 — 133 ns
21 Write data hold time, tDHW = 1/8 tCYC–30 ns(2)a tDHW 95 — 33 — ns
22 Multiplexed address valid time to E rise
tAVM = PWEL –(tASD + 90 ns)(2)a tAVM 268 — 78 — ns
24 Multiplexed address valid time to AS fall
tASL = PWASH –70 ns tASL 150 — 25 — ns
25 Multiplexed address hold time, tAHL = 1/8 tCYC–30 ns(2)b tAHL 95 — 33 — ns
26 Delay time, E to AS rise, tASD = 1/8 tCYC–5 ns(2)a tASD 120 — 58 — ns
27 Pulse width, AS high, PWASH = 1/4 tCYC–30 ns PWASH 220 — 95 — ns
28 Delay time, AS to E rise, tASED = 1/8 tCYC–5 ns(2)b tASED 120 — 58 — ns
29 MPU address access time(3)a
tACCA = tCYC–(PWEL–tAVM) –tDSR–tf
tACCA 735 — 298 — ns
35 MPU access time, tACCE = PWEH –tDSR tACCE — 440 — 190 ns
36 Multiplexed address delay (Previous cycle MPU read)
tMAD = tASD + 30 ns(2)a tMAD 150 — 88 — ns
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
170 Freescale Semiconductor
Figure 10-14. Multiplexed Expansion Bus Timing Diagram
E
AS
1
4A
9
ADDRESS/DATA
(MULTIPLEXED)
READ
WRITE
12
2 3 4B
4A 4B
29
35 17
18
19 21
25
24
27
36 22
26 28
ADDRESS
ADDRESS
DATA
DATA
R/W, ADDRESS
(NON-MUX)
NOTE: Measurement points shown are 20% and 70% of V DD.
MUX BUS TI
M
1
2 3 4B
4A
12
36
22 35 17
29 18
9
2119
4A
25
24 4B
26 27 28
E
R/W, ADDRESS
NON-MULTIPLEXED
ADDRESS/DATA
MULTIPLEXED
AS
READ
WRITE
ADDRESS DATA
ADDRESS DATA
Note: Measurement points shown are 20% and 70% of VDD.
Serial Peripheral Interface Timing Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 171
10.17 Serial Peripheral Interface Timing Characteristics
Num Characteristic(1)
1. VDD = 5.0 Vdc ±10%, VSS = 0 Vdc, TA = TL to TH, all timing is shown with respect to 20% VDD and 70% VDD, unless other-
wise noted
Symbol E9 E20 Unit
Min Max Min Max
Frequency of operation
E clock fodc 3.0 dc 3.0 MHz
E-clock period tCYC 333 — 333 — ns
Operating frequency
Master
Slave
fop(m)
fop(s)
fo/32
dc
fo/2
fo
fo/128
dc
fo/2
fo
MHz
1
Cycle time
Master
Slave
tCYC(m)
tCYC(s)
2
1
32
—
2
1
128
—
tCYC
2Enable lead time(2)
Slave
2. Time to data active from high-impedance state
tlead(s) 1—1—
tCYC
3Enable lag time(2)
Slave tlag(s) 1—1—
tCYC
4
Clock (SCK) high time
Master
Slave
tw(SCKH)m
tw(SCKH)s
tCYC–25
1/2
tCYC–25
16 tCYC
—
tCYC–25
1/2
tCYC–25
64 tCYC
—
ns
5
Clock (SCK) low time
Master
Slave
tw(SCKL)m
tw(SCKL)s
tCYC–25
1/2
tCYC–25
16 tCYC
—
tCYC–25
1/2
tCYC–25
64 tCYC
—
ns
6
Data setup time (inputs)
Master
Slave
tsu(m)
tsu(s)
30
30
—
—
30
30
—
—
ns
7
Data hold time (inputs)
Master
Slave
th(m)
th(s)
30
30
—
—
30
30
—
—
ns
8
Slave access time
CPHA = 0
CPHA = 1
ta0
0
40
40
0
0
40
40
ns
9
Disable time (hold time
to high-impedance state)
Slave
tdis —50—50ns
10 Data valid(3) (after enable edge)
3. Assumes 200 pF load on SCK, MOSI, and MISO pins
tv—50—50ns
11 Data hold time (outputs)
(after enable edge) tho 0—0—ns
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
172 Freescale Semiconductor
10.18 MC68L11E9/E20 Serial Peirpheral Interface Characteristics
Num Characteristic(1)
1. VDD = 3.0 Vdc to 5.5 Vdc, VSS = 0 Vdc, TA = TL to TH, all timing is shown with respect to 20% VDD and 70% VDD, unless
otherwise noted
Symbol E9 E20 Unit
Min Max Min Max
Frequency of operation
E clock fodc 2.0 dc 2.0 MHz
E-clock period tCYC 500 — 500 — ns
Operating frequency
Master
Slave
fop(m)
fop(s)
fo/32
dc
fo/2
fo
fo/128
dc
fo/2
fo
MHz
1
Cycle time
Master
Slave
tCYC(m)
tCYC(s)
2
1
32
—
2
1
128
—
tCYC
2Enable lead time(2)
Slave
2. Time to data active from high-impedance state
tlead(s) 1—1—
tCYC
3Enable lag time(2)
Slave tlag(s) 1—1—
tCYC
4
Clock (SCK) high time
Master
Slave
tw(SCKH)m
tw(SCKH)s
tCYC–30
1/2
tCYC–30
16 tCYC
—
tCYC–30
1/2
tCYC–30
64 tCYC
—
ns
5
Clock (SCK) low time
Master
Slave
tw(SCKL)m
tw(SCKL)s
tCYC–30
1/2
tCYC–30
16 tCYC
—
tCYC–30
1/2
tCYC–30
64 tCYC
—
ns
6
Data setup time (inputs)
Master
Slave
tsu(m)
tsu(s)
40
40
—
—
40
40
—
—
ns
7
Data hold time (inputs)
Master
Slave
th(m)
th(s)
40
40
—
—
40
40
—
—
ns
8
Slave access time
CPHA = 0
CPHA = 1
ta0
0
50
50
0
0
50
50
ns
9
Disable time (hold time
to high-impedance state)
Slave
tdis —60—60ns
10 Data valid(3) (after enable edge)
3. Assumes 100 pF load on SCK, MOSI, and MISO pins
tv—60—60ns
11 Data hold time (outputs)
(after enable edge) tho 0—0—ns
MC68L11E9/E20 Serial Peirpheral Interface Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 173
A) SPI Master Timing (CPHA = 0)
B) SPI Master Timing (CPHA = 1)
Figure 10-15. SPI Timing Diagram (Sheet 1 of 2)
SCK
INPUT
SCK
OUTPUT
MISO
INPUT
MOSI
OUTPUT
SS
INPUT
1
11
6 7
MSB IN
BIT 6 . . . 1
LSB IN
MASTER MSB OUT MASTER LSB OUT
BIT 6 . . . 1
11 (REF)
5
4
CPOL = 0
CPOL = 1
SS IS HELD HIGH ON MASTER.
SEE NOTE
SEE NOTE
Note: This first clock edge is generated internally but is not seen at the SCK pin.
5
4
10
SCK
INPUT
SCK
OUTPUT
MISO
INPUT
MOSI
OUTPUT
SS
INPUT
1
11
MSB IN
BIT 6 . . . 1
LSB IN
MASTER MSB OUT MASTER LSB OUT
BIT 6 . . . 1
11 (REF)
5
4
CPOL = 0
CPOL = 1
SS IS HELD HIGH ON MASTER.
SEE NOTE
SEE NOTE
Note: This first clock edge is generated internally but is not seen at the SCK pin.
5
4
10
10 (REF)
67
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
174 Freescale Semiconductor
A) SPI Slave Timing (CPHA = 0)
B) SPI Slave Timing (CPHA = 1)
Figure 11-15. SPI Timing Diagram (Sheet 2 of 2)
SCK
INPUT
SCK
INPUT
MOSI
INPUT
MISO
OUTPUT
SS
INPUT
1
6 7
MSB IN
BIT 6 . . . 1
LSB IN
MSB OUT SLAVE LSB OUT
BIT 6 . . . 1
4
4
2
8
CPOL = 0
CPOL = 1
3
Note: Not defined but normally MSB of character just received
SLAVE
11
SEE
NOTE
9
5
5
10 11
SCK
INPUT
SCK
INPUT
MOSI
INPUT
MISO
OUTPUT
SS
INPUT
1
6 7
MSB IN
BIT 6 . . . 1
LSB IN
MSB OUT SLAVE LSB OUT
BIT 6 . . . 1
4
2
8
CPOL = 0
CPOL = 1
3
Note: Not defined but normally LSB of character previously transmitted
SLAVE
11
SEE
NOTE
9
5
5
10
10
4
EEPROM Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 175
10.19 EEPROM Characteristics
10.20 MC68L11E9/E20 EEPROM Characteristics
10.21 EPROM Characteristics
Characteristic(1)
1. VDD = 5.0 Vdc ±10%, VSS = 0 Vdc, TA = TL to TH
Temperature Range Unit
–40 to 85°C –40 to 105°C –40 to 125°C
Programming time(2)
< 1.0 MHz, RCO enabled
1.0 to 2.0 MHz, RCO disabled
≥ 2.0 MHz (or anytime RCO enabled)
10
20
10
15
Must use RCO
15
20
Must use RCO
20
ms
Erase time(2)
Byte, row, and bulk
2. The RC oscillator (RCO) must be enabled (by setting the CSEL bit in the OPTION register) for EEPROM programming and
erasure when the E-clock frequency is below 1.0 MHz.
10 10 10 ms
Write/erase endurance 10,000 10,000 10,000 Cycles
Data retention 10 10 10 Years
Characteristic(1)
1. VDD = 3.0 Vdc to 5.5 Vdc, VSS = 0 Vdc, TA = TL to TH
Temperature Range
–20 to 70°CUnit
Programming time(2)
3 V, E ≤ 2.0 MHz, RCO enabled
5 V, E ≤ 2.0 MHz, RCO enabled
2. The RC oscillator (RCO) must be enabled (by setting the CSEL bit in the OPTION register) for EEPROM programming and
erasure.
25
10
ms
Erase time(2) (byte, row, and bulk)
3 V, E ≤ 2.0 MHz, RCO enabled
5 V, E ≤ 2.0 MHz, RCO enabled
25
10
ms
Write/erase endurance 10,000 Cycles
Data retention 10 Years
Characteristics(1)
1. VDD = 5.0 Vdc ± 10%
Symbol Min Typ Max Unit
Programming voltage(2)
2. During EPROM programming of the MC68HC711E9 device, the VPPE pin circuitry may latch-up and be damaged if the
input current is not limited to 10 mA. For more information please refer to MC68HC711E9 8-Bit Microcontroller Unit Mask
Set Errata 3 (Freescale document order number 68HC711E9MSE3.
VPPE 11.75 12.25 12.75 V
Programming current(3)
3. Typically, a 1-kΩ series resistor is sufficient to limit the programming current for the MC68HC711E9. A 100-Ω series resis-
tor is sufficient to limit the programming current for the MC68HC711E20.
IPPE —310mA
Programming time tEPROG 224ms
Electrical Characteristics
M68HC11E Family Data Sheet, Rev. 5.1
176 Freescale Semiconductor
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 177
Chapter 11
Ordering Information and Mechanical Specifications
11.1 Introduction
This section provides ordering information for the E-series devices grouped by:
• Standard devices
• Custom ROM devices
• Extended voltage devices
In addition, mechanical specifications for the following packaging options:
• 52-pin plastic-leaded chip carrier (PLCC)
• 52-pin windowed ceramic-leaded chip carrier (CLCC)
• 64-pin quad flat pack (QFP)
• 52-pin thin quad flat pack (TQFP)
• 56-pin shrink dual in-line package with .070-inch lead spacing (SDIP)
• 48-pin plastic DIP (.100-inch lead spacing), MC68HC811E2 only
11.2 Standard Device Ordering Information
Description CONFIG Temperature Frequency MC Order Number
52-pin plastic leaded chip carrier (PLCC)
BUFFALO ROM $0F –40°C to +85°C2 MHz MC68HC11E9BCFN2
3 MHz MC68HC11E9BCFN3
No ROM $0D
–40°C to +85°C2 MHz MC68HC11E1CFN2
3 MHz MC68HC11E1CFN3
–40°C to +105°C 2 MHz MC68HC11E1VFN2
–40°C to +125°C 2 MHz MC68HC11E1MFN2
No ROM, no EEPROM $0C
–40°C to +85°C2 MHz MC68HC11E0CFN2
3 MHz MC68HC11E0CFN3
–40°C to +105°C 2 MHz MC68HC11E0VFN2
–40°C to +125°C 2 MHz MC68HC11E0MFN2
Ordering Information and Mechanical Specifications
M68HC11E Family Data Sheet, Rev. 5.1
178 Freescale Semiconductor
52-pin plastic leaded chip carrier (PLCC) (Continued)
OTPROM $0F
–40°C to +85°C2 MHz MC68HC711E9CFN2
3 MHz MC68HC711E9CFN3
–40°C to +105°C 2 MHz MC68HC711E9VFN2
–40°C to +125°C 2 MHz MC68HC711E9MFN2
OTPROM, enhanced security
feature $0F –40°C to +85°C 2 MHz MC68S711E9CFN2
20 Kbytes OTPROM $0F
0°C to +70°C 3 MHz MC68HC711E20FN3
–40°C to +85°C2 MHz MC68HC711E20CFN2
3 MHz MC68HC711E20CFN3
–40°C to +105°C 2 MHz MC68HC711E20VFN2
–40°C to +125°C 2 MHz MC68HC711E20MFN2
No ROM, 2 Kbytes EEPROM $FF
0°C to +70°C 2 MHz MC68HC811E2FN2
–40°C to +85°C 2 MHz MC68HC811E2CFN2
–40°C to +105°C 2 MHz MC68HC811E2VFN2
–40°C to +125°C 2 MHz MC68HC811E2MFN2
64-pin quad flat pack (QFP)
BUFFALO ROM $0F –40°C to +85°C2 MHz MC68HC11E9BCFU2
3 MHz MC68HC11E9BCFU3
No ROM $0D –40°C to +85°C2 MHz MC68HC11E1CFU2
3 MHz MC68HC11E1CFU3
–40°C to +105°C 2 MHz MC68HC11E1VFU2
No ROM, no EEPROM $0C –40°C to +85°C 2 MHz MC68HC11E0CFU2
–40°C to +105°C 2 MHz MC68HC11E0VFU2
20 Kbytes OTPROM $0F
0°C to +70°°C 3 MHz MC68HC711E20FU3
–40°C to +85°C2 MHz MC68HC711E20CFU2
3 MHz MC68HC711E20CFU3
–40°C to +105°C 2 MHz MC68HC711E20VFU2
–40°C to +125°C 2 MHz MC68HC711E20MFU2
52-pin thin quad flat pack (TQFP)
BUFFALO ROM $0F –40°C to +85°C2 MHz MC68HC11E9BCPB2
3 MHz MC68HC11E9BCPB3
Description CONFIG Temperature Frequency MC Order Number
Custom ROM Device Ordering Information
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 179
11.3 Custom ROM Device Ordering Information
52-pin windowed ceramic leaded chip carrier (CLCC)
EPROM $0F
–40°C to +85°C2 MHz MC68HC711E9CFS2
3 MHz MC68HC711E9CFS3
–40°C to +105°C 2 MHz MC68HC711E9VFS2
–40°C to +125°C 2 MHz MC68HC711E9VFS2
20 Kbytes EPROM $0F
0°C o +70°°C 3 MHz MC68HC711E20FS3
–40°C to +85°C2 MHz MC68HC711E20CFS2
3 MHz MC68HC711E20CFS3
–40°C to +105°C 2 MHz MC68HC711E20VFS2
–40°C to +125°C 2 MHz MC68HC711E20MFS2
48-pin dual in-line package (DIP) — MC68HC811E2 only
No ROM, 2 Kbytes EEPROM $FF
0°C to +70°°C 2 MHz MC68HC811E2P2
–40°C to +85°C 2 MHz MC68HC811E2CP2
–40°C to +105°C 2 MHz MC68HC811E2VP2
–40°C to +125°C 2 MHz MC68HC811E2MP2
56-pin dual in-line package with 0.70-inch lead spacing (SDIP)
BUFFALO ROM $0F –40°C to +85°C2 MHz MC68HC11E9BCB2
3 MHz MC68HC11E9BCB3
No ROM $0D
–40°C to +85°C2 MHz MC68HC11E1CB2
3 MHz MC68HC11E1CB3
–40°C to +105°C 2 MHz MC68HC11E1VB2
–40°C to +125°C 2 MHz MC68HC11E1MB2
No ROM, no EEPROM $0C
–40°C to +85°C2 MHz MC68HC11E0CB2
3 MHz MC68HC11E0CB3
–40°C to +105°C 2 MHz MC68HC11E0VB2
–40°C to +125°C 2 MHz MC68HC11E0MB2
Description Temperature Frequency MC Order Number
52-pin plastic leaded chip carrier (PLCC)
Custom ROM
0°C to +70°°C 3 MHz MC68HC11E9FN3
–40°C to +85°C2 MHz MC68HC11E9CFN2
3 MHz MC68HC11E9CFN3
–40°C to +105°C 2 MHz MC68HC11E9VFN2
–40°C to +125°C 2 MHz MC68HC11E9MFN2
Description CONFIG Temperature Frequency MC Order Number
Ordering Information and Mechanical Specifications
M68HC11E Family Data Sheet, Rev. 5.1
180 Freescale Semiconductor
20 Kbytes custom ROM
0°C to +70°°C 3 MHz MC68HC11E20FN3
–40°C to +85°C2 MHz MC68HC11E20CFN2
3 MHz MC68HC11E20CFN3
–40°C to +105°C 2 MHz MC68HC11E20VFN2
–40°C to +125°C 2 MHz MC68HC11E20MFN2
64-pin quad flat pack (QFP)
Custom ROM
0°C to +70°°C 3 MHz MC68HC11E9FU3
–40°C to +85°C2 MHz MC68HC11E9CFU2
3 MHz MC68HC11E9CFU3
–40°C to +105°C 2 MHz MC68HC11E9VFU2
–40°C to +125°C 2 MHz MC68HC11E9MFU2
64-pin quad flat pack (continued)
20 Kbytes Custom ROM
0°C to +70°°C 3 MHz MC68HC11E20FU3
–40°C to +85°C2 MHz MC68HC11E20CFU2
3 MHz MC68HC11E20CFU3
–40°C to +105°C 2 MHz MC68HC11E20VFU2
–40°C to +125°C 2 MHz MC68HC11E20MFU2
52-pin thin quad flat pack (10 mm x 10 mm)
Custom ROM
0°C to +70°°C 3 MHz MC68HC11E9PB3
–40°C to +85°C2 MHz MC68HC11E9CPB2
3 MHz MC68HC11E9CPB3
–40°C to +105°C 2 MHz MC68HC11E9VPB2
–40°C to +125°C 2 MHz MC68HC11E9MPB2
56-pin dual in-line package with 0.70-inch lead spacing (SDIP)
Custom ROM
0°C to +70°°C 3 MHz MC68HC11E9B3
–40°C to +85°C2 MHz MC68HC11E9CB2
3 MHz MC68HC11E9CB3
–40°C to +105°C 2 MHz MC68HC11E9VB2
–40°C to +125°C 2 MHz MC68HC11E9MB2
Description Temperature Frequency MC Order Number
Extended Voltage Device Ordering Information (3.0 Vdc to 5.5 Vdc)
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 181
11.4 Extended Voltage Device Ordering Information (3.0 Vdc to 5.5 Vdc)
Description Temperature Frequency MC Order Number
52-pin plastic leaded chip carrier (PLCC)
Custom ROM
–20°C to +70°C
2 MHz MC68L11E9FN2
MC68L11E20FN2
No ROM 2 MHz MC68L11E1FN2
No ROM, no EEPROM 2 MHz MC68L11E0FN2
64-pin quad flat pack (QFP)
Custom ROM
–20°C to +70°C
2 MHz MC68L11E9FU2
MC68L11E20FU2
No ROM 2 MHz MC68L11E1FU2
No ROM, no EEPROM 2 MHz MC68L11E0FU2
52-pin thin quad flat pack (10 mm x 10 mm)
Custom ROM
–20°C to +70°C
2 MHz MC68L11E9PB2
No ROM 2 MHz MC68L11E1PB2
No ROM, no EEPROM 2 MHz MC68L11E0PB2
56-pin dual in-line package with 0.70-inch lead spacing (SDIP)
Custom ROM
–20°C to +70°C
2 MHz MC68L11E9B2
No ROM 2 MHz MC68L11E1B2
No ROM, no EEPROM 2 MHz MC68L11E0B2
Ordering Information and Mechanical Specifications
M68HC11E Family Data Sheet, Rev. 5.1
182 Freescale Semiconductor
11.5 52-Pin Plastic-Leaded Chip Carrier (Case 778)
–L–
YBRK
W
D
D
V
52 1
NOTES:
1. DATUMS –L–, –M–, AND –N– DETERMINED WHERE
TOP OF LEAD SHOULDER EXITS PLASTIC BODY AT
MOLD PARTING LINE.
2. DIMENSION G1, TRUE POSITION TO BE MEASURED
AT DATUM –T–, SEATING PLANE.
3. DIMENSIONS R AND U DO NOT INCLUDE MOLD
FLASH. ALLOWABLE MOLD FLASH IS 0.010 (0.250)
PER SIDE.
4. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
5. CONTROLLING DIMENSION: INCH.
6. THE PACKAGE TOP MAY BE SMALLER THAN THE
PACKAGE BOTTOM BY UP TO 0.012 (0.300).
DIMENSIONS R AND U ARE DETERMINED AT THE
OUTERMOST EXTREMES OF THE PLASTIC BODY
EXCLUSIVE OF MOLD FLASH, TIE BAR BURRS, GATE
BURRS AND INTERLEAD FLASH, BUT INCLUDING
ANY MISMATCH BETWEEN THE TOP AND BOTTOM
OF THE PLASTIC BODY.
7. DIMENSION H DOES NOT INCLUDE DAMBAR
PROTRUSION OR INTRUSION. THE DAMBAR
PROTRUSION(S) SHALL NOT CAUSE THE H
DIMENSION TO BE GREATER THAN 0.037 (0.940).
THE DAMBAR INTRUSION(S) SHALL NOT CAUSE THE
H DIMENSION TO BE SMALLER THAN 0.025 (0.635).
B
U
Z
G1
X
VIEW D–D
H
K1
KF
VIEW S
M
0.007 (0.18) L–M S
TS
N
M
0.007 (0.18) L–M S
TS
N
0.004 (0.100)
–T–
SEATING
PLANE
M
0.007 (0.18) L–M S
TS
N
M
0.007 (0.18) L–M S
TS
N
A
R
G
G1
C
Z
J
E
VIEW S
–M–
–N–
DIM MIN MAX MIN MAX
MILLIMETERSINCHES
A0.785 0.795 19.94 20.19
B0.785 0.795 19.94 20.19
C0.165 0.180 4.20 4.57
E0.090 0.110 2.29 2.79
F0.013 0.019 0.33 0.48
G0.050 BSC 1.27 BSC
H0.026 0.032 0.66 0.81
J0.020 ––– 0.51 –––
K0.025 ––– 0.64 –––
R0.750 0.756 19.05 19.20
U0.750 0.756 19.05 19.20
V0.042 0.048 1.07 1.21
W0.042 0.048 1.07 1.21
X0.042 0.056 1.07 1.42
Y––– 0.020 ––– 0.50
Z2 10 2 10
G1 0.710 0.730 18.04 18.54
K1 0.040 ––– 1.02 –––
____
M
0.007 (0.18) L–M S
TS
N
M
0.007 (0.18) L–M S
TS
N
S
0.010 (0.25) L–M S
TS
N
S
0.010 (0.25) L–M S
TS
N
52-Pin Windowed Ceramic-Leaded Chip Carrier (Case 778B)
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 183
11.6 52-Pin Windowed Ceramic-Leaded Chip Carrier (Case 778B)
0.15 (0.006)
-T- SEATING
PLANE
M
0.51 (0.020) A S
TS
B
G
C
K
H
-B-
NOTES:
1. DIMENSIONING AND TOLERANCING PER
ANSI Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION R AND N DO NOT INCLUDE
GLASS PROTRUSION. GLASS PROTRUSION
TO BE 0.25 (0.010) MAXIMUM.
4. ALL DIMENSIONS AND TOLERANCES
INCLUDE LEAD TRIM OFFSET AND LEAD
DIM MIN MAX MIN MAX
MILLIMETERSINCHES
A0.785 0.795 19.94 20.19
B0.785 0.795 19.94 20.19
C0.165 0.200 4.20 5.08
D0.017 0.021 0.44 0.53
F0.026 0.032 0.67 0.81
G0.050 BSC 1.27 BSC
H0.090 0.130 2.29 3.30
J0.006 0.010 0.16 0.25
K0.035 0.045 0.89 1.14
N0.735 0.756 18.67 19.20
R0.735 0.756 18.67 19.20
S0.690 0.730 17.53 18.54
N
R
-A-
M
0.51 (0.020) A S
TS
B
S
F
J
M
0.18 (0.007) A S
TS
B
D52 PL
Ordering Information and Mechanical Specifications
M68HC11E Family Data Sheet, Rev. 5.1
184 Freescale Semiconductor
11.7 64-Pin Quad Flat Pack (Case 840C)
ÇÇÇÇ
Ç
ÇÇ
Ç
ÇÇÇÇ
ÉÉÉÉ
ÉÉÉÉ
GH
EC
DETAIL A
L
A
48
S
L
–D–
–A–
–B–
0.05 (0.002) A–B
S
A–B
M
0.20 (0.008) D S
H
S
A–B
M
0.20 (0.008) D S
C
BV
0.05 (0.002) D
S
A–B
M
0.20 (0.008) D S
H
S
A–B
M
0.20 (0.008) D S
C
SEATING PLANE
DATUM PLANE
–C–
–H–
49
33
32
64 17
116
DETAIL C
0.10 (0.004)
S
A–B
M
0.20 (0.008) D S
C
SECTION B–B
F
N
D
BASE
J
METAL
DETAIL A
P
BB –A–, –B–, –D–
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DATUM PLANE –H– IS LOCATED AT BOTTOM OF
LEAD AND IS COINCIDENT WITH THE LEAD
WHERE THE LEAD EXITS THE PLASTIC BODY AT
THE BOTTOM OF THE PARTING LINE.
4. DATUMS A–B AND –D– TO BE DETERMINED AT
DATUM PLANE –H–.
5. DIMENSIONS S AND V TO BE DETERMINED AT
SEATING PLANE –C–.
6. DIMENSIONS A AND B DO NOT INCLUDE MOLD
PROTRUSION. ALLOWABLE PROTRUSION IS 0.25
(0.010) PER SIDE. DIMENSIONS A AND B DO
INCLUDE MOLD MISMATCH AND ARE
DETERMINED AT DATUM PLANE –H–.
7. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. DAMBAR PROTRUSION SHALL
NOT CAUSE THE D DIMENSION TO EXCEED 0.53
(0.021). DAMBAR CANNOT BE LOCATED ON THE
LOWER RADIUS OR THE FOOT.
8. DIMENSION K IS TO BE MEASURED FROM THE
THEORETICAL INTERSECTION OF LEAD FOOT
AND LEG CENTERLINES.
DIM MIN MAX MIN MAX
INCHESMILLIMETERS
A13.90 14.10 0.547 0.555
B13.90 14.10 0.547 0.555
C2.07 2.46 0.081 0.097
D0.30 0.45 0.012 0.018
E2.00 0.079
F0.30 0.012
G0.80 BSC 0.031 BSC
–––
H0.067 0.250 0.003 0.010
J0.130 0.230 0.005 0.090
K0.50 0.66 0.020 0.026
L12.00 REF 0.472 REF
M5 10 5 10
N0.130 0.170 0.005 0.007
P0.40 BSC 0.016 BSC
Q2 8 2 8
R0.13 0.30 0.005 0.012
S16.20 16.60 0.638 0.654
T0.20 REF 0.008 REF
U0 ––– 0 –––
V16.20 16.60 0.638 0.654
X1.10 1.30 0.043 0.051
2.40 0.094
–––
DETAIL C
SEATING PLANE
M
U
T
R
Q
K
X
M
_
_
_
___
___
_
52-Pin Thin Quad Flat Pack (Case 848D)
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 185
11.8 52-Pin Thin Quad Flat Pack (Case 848D)
F
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: MILLIMETER.
3. DATUM PLANE –H– IS LOCATED AT BOTTOM OF
LEAD AND IS COINCIDENT WITH THE LEAD
WHERE THE LEAD EXITS THE PLASTIC BODY AT
THE BOTTOM OF THE PARTING LINE.
4. DATUMS –L–, –M– AND –N– TO BE DETERMINED
AT DATUM PLANE –H–.
5. DIMENSIONS S AND V TO BE DETERMINED AT
SEATING PLANE –T–.
6. DIMENSIONS A AND B DO NOT INCLUDE MOLD
PROTRUSION. ALLOWABLE PROTRUSION IS
0.25 (0.010) PER SIDE. DIMENSIONS A AND B
DO INCLUDE MOLD MISMATCH AND ARE
DETERMINED AT DATUM PLANE -H-.
7. DIMENSION D DOES NOT INCLUDE DAMBAR
PROTRUSION. DAMBAR PROTRUSION SHALL
NOT CAUSE THE LEAD WIDTH TO EXCEED 0.46
(0.018). MINIMUM SPACE BETWEEN
PROTRUSION AND ADJACENT LEAD OR
PROTRUSION 0.07 (0.003).
ÉÉÉÉ
ÉÉÉÉ
ÇÇÇÇ
ÇÇÇÇ
VIEW AA
VIEW AA
2 X R
R1
AB
AB
VIEW Y
SECTION AB–AB
ROTATED 90
_
CLOCKWISE
DIM
A
MIN MAX MIN MAX
INCHES
10.00 BSC 0.394 BSC
MILLIMETERS
A1 5.00 BSC 0.197 BSC
B10.00 BSC 0.394 BSC
B1 5.00 BSC 0.197 BSC
C––– 1.70 ––– 0.067
C1 0.05 0.20 0.002 0.008
C2 1.30 1.50 0.051 0.059
D0.20 0.40 0.008 0.016
E0.45 0.030
F0.22 0.35 0.009 0.014
G0.65 BSC
0.75 0.018
0.026 BSC
J0.07 0.20 0.003 0.008
K0.50 REF 0.020 REF
R1 0.08 0.20 0.003 0.008
S12.00 BSC 0.472 BSC
S1 6.00 BSC 0.236 BSC
U0.09 0.16 0.004 0.006
V12.00 BSC 0.472 BSC
V1 6.00 BSC 0.236 BSC
W0.20 REF 0.008 REF
Z1.00 REF 0.039 REF
C
L
–X–
X=L, M, N
1
13
14 26
27
39
4052
4X TIPS
4X
N0.20 (0.008) H L–M N0.20 (0.008) T L–M
3X
VIEW Y
SEATING
PLANE
C0.10 (0.004) T
4X
θ3
4X
θ2
S
0.05 (0.002)
0.25 (0.010)
GAGE PLANE
C2
C1
W
K
E
Z
S
L–M
M
0.13 (0.005) N
S
T
PLATING
BASE METAL
D
JU
B V
B1
A
S
V1
A1
S1
–L–
–N–
–M–
–H–
–T–
θ1
θ
G
θ1
θ
θ3
θ2
07
__
12
513
___
07
__
0
_
0
_
––– –––
REF 12
_
REF
13
_
5
_
Ordering Information and Mechanical Specifications
M68HC11E Family Data Sheet, Rev. 5.1
186 Freescale Semiconductor
11.9 56-Pin Dual in-Line Package (Case 859)
11.10 48-Pin Plastic DIP (Case 767)
NOTE
The MC68HC811E2 is the only member of the E series that is offered in a
48-pin plastic dual in-line package.
–A–
–B–
–T–
56 29
128
SEATING
PLANE
J56 PL
D56 PL
S
A
M
0.25 (0.010) T
N
FG
E
S
B
M
0.25 (0.010) T
K
CH
L
M
DIM MIN MAX MIN MAX
MILLIMETERSINCHES
A2.035 2.065 51.69 52.45
B0.540 0.560 13.72 14.22
C0.155 0.200 3.94 5.08
D0.014 0.022 0.36 0.56
E0.035 BSC 0.89 BSC
F0.032 0.046 0.81 1.17
G0.070 BSC 1.778 BSC
H0.300 BSC 7.62 BSC
J0.008 0.015 0.20 0.38
K0.115 0.135 2.92 3.43
L0.600 BSC 15.24 BSC
M0 15 0 15
N0.020 0.040 0.51 1.02
____
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION L TO CENTER OF LEAD WHEN
FORMED PARALLEL.
4. DIMENSIONS A AND B DO NOT INCLUDE MOLD
FLASH. MAXIMUM MOLD FLASH 0.25 (0.010)
-A-
-B-
48 25
124
-T-
SEATING
PLANE
FG
DETAIL X
32 PLD
48 PLJ
S
B
M
0.25 (0.010) T
S
A
M
0.51 (0.020) T
N
C
K
48 PLM
DETAIL X
L
TIP TAPER
NOTES:
1. DIMENSIONING AND TOLERANCING PER ANSI
Y14.5M, 1982.
2. CONTROLLING DIMENSION: INCH.
3. DIMENSION L TO CENTER OF LEAD WHEN FORMED
PARALLEL.
4. DIMENSIONS A AND B DO NOT INCLUDE MOLD FLASH.
MAXIMUM MOLD FLASH 0.25 (0.010).
DIM MIN MAX MIN MAX
MILLIMETERSINCHES
A2.415 2.445 61.34 62.10
B0.540 0.560 13.72 14.22
C0.155 0.200 3.94 5.08
D0.014 0.022 0.36 0.55
F0.040 0.060 1.02 1.52
G0.100 BSC 2.54 BSC
H0.070 BSC 1.79 BSC
J0.008 0.015 0.20 0.38
K0.115 0.150 2.92 3.81
L0.600 BSC 15.24 BSC
M0 15 0 15
N0.020 0.040 0.51 1.01
××××
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 187
Appendix A
Development Support
A.1 Introduction
This section provides information on the development support offered for the E-series devices.
A.2 M68HC11 E-Series Development Tools
A.3 EVS — Evaluation System
The EVS is an economical tool for designing, debugging, and evaluating target systems based on the
M68HC11. EVS features include:
• Monitor/debugger firmware
• One-line assembler/disassembler
• Host computer download capability
• Dual memory maps:
– 64-Kbyte monitor map that includes 16 Kbytes of monitor EPROM
– M68HC11 E-series user map that includes 64 Kbytes of emulation RAM
• MCU extension input/output (I/O) port for single-chip, expanded, and special-test operation modes
• RS-232C terminal and host I/O ports
• Logic analyzer connector
Device Package Emulation
Module(1) (2)
1. Each MMDS11 system consists of a system console (M68MMDS11), an emulation module, a flex cable, and a target head.
2. A complete EVS consists of a platform board (M68HC11PFB), an emulation module, a flex cable, and a target head.
Flex
Cable(1) (2)
MMDS11
Target Head(1) (2)
SPGMR
Programming
Adapter(3)
3. Each SPGMR system consists of a universal serial programmer (M68SPGMR11) and a programming adapter. It can be
used alone or in conjunction with the MMDS11.
MC68HC11E9
MC68HC711E9
52 FN M68EM11E20 M68CBL11C M68TC11E20FN52 M68PA11E20FN52
52 PB M68EM11E20 M68CBL11C M68TC11E20PB52 M68PA11E20PB52
56 B M68EM11E20 M68CBL11B M68TC11E20B56 M68PA11E20B56
64 FU M68EM11E20 M68CBL11C M68TC11E20FU64 M68PA11E20FU64
MC68HC11E20
MC68HC711E20
52 FN M68EM11E20 M68CBL11C M68TC11E20FN52 M68PA11E20FN52
64 FU M68EM11E20 M68CBL11C M68TC11E20FU64 M68PA11E20FU64
MC68HC811E2 48 P M68EM11E20 M68CBL11B M68TB11E20P48 M68PA11A8P48
52 FN M68EM11E20 M68CBL11C M68TC11E20FN52 M68PA11E20FN52
Development Support
M68HC11E Family Data Sheet, Rev. 5.1
188 Freescale Semiconductor
A.4 Modular Development System (MMDS11)
The M68MMDS11 modular development system (MMDS11) is an emulator system for developing
embedded systems based on an M68HC11 microcontroller unit (MCU). The MMDS11 provides a bus
state analyzer (BSA) and real-time memory windows. The unit's integrated development environment
includes an editor, an assembler, user interface, and source-level debug. These features significantly
reduce the time necessary to develop and debug an embedded MCU system. The unit's compact size
requires a minimum of desk space.
The MMDS11 is one component of Freescale's modular approach to MCU-based product development.
This modular approach allows easy configuration of the MMDS11 to fit a wide range of requirements. It
also reduces development system cost by allowing the user to purchase only the modular components
necessary to support the particular MCU derivative.
MMDS11 features include:
• Real-time, non-intrusive, in-circuit emulation at the MCU’s operating frequency
• Real-time bus state analyzer
– 8 K x 64 real-time trace buffer
– Display of real-time trace data as raw data, disassembled instructions, raw data and
disassembled instructions, or assembly-language source code
– Four hardware triggers for commencing trace and to provide breakpoints
– Nine triggering modes
– As many as 8190 pre- or post-trigger points for trace data
– 16 general-purpose logic clips, four of which can be used to trigger the bus state analyzer
sequencer
– 16-bit time tag or an optional 24-bit time tag that reduces the logic clips traced from 16 to eight
• Four data breakpoints (hardware breakpoints)
• Hardware instruction breakpoints over either the 64-Kbyte M68HC11 memory map or over a
1-Mbyte bank switched memory map
• 32 real-time variables, nine of which can be displayed in the variables window. These variables
may be read or written while the MCU is running
• 32 bytes of real-time memory can be displayed in the memory window. This memory may be read
or written while the MCU is running
• 64 Kbytes of fast emulation memory (SRAM)
• Current-limited target input/output connections
• Six software-selectable oscillator clock sources: five internally generated frequencies and an
external frequency via a bus analyzer logic clip
• Command and response logging to MS-DOS® disk files to save session history
• SCRIPT command for automatic execution of a sequence of MMDS11 commands
• Assembly or C-language source-level debugging with global variable viewing
• Host/emulator communications speeds as high as 57,600 baud for quick program loading
® MS-DOS is a registered trademark of Microsoft Corporation.
SPGMR11 — Serial Programmer for M68HC11 MCUs
M68HC11E Family Data Sheet, Rev. 5.1
Freescale Semiconductor 189
• Extensive on-line MCU information via the CHIPINFO command. View memory map, vectors,
register, and pinout information pertaining to the device being emulated
• Host software supports:
– An editor
– An assembler and user interface
– Source-level debug
– Bus state analysis
–IBM
® mouse
A.5 SPGMR11 — Serial Programmer for M68HC11 MCUs
The SPGMR11 is a modular EPROM/EEPROM programming tool for all M68HC11 devices. The
programmer features interchangeable adapters that allow programming of various M68HC11 package
types.
Programmer features include:
• Programs M68HC11 Family devices that contain an EPROM or EEPROM array.
• Can be operated as a stand-alone programmer connected to a host computer or connected
between a host computer and the M68HC11 modular development system (MMDS11) station
module
• Uses plug-in programming adapters to accommodate a variety of MCU devices and packages
• On-board programming voltage circuit eliminates the need for an external 12-volt supply.
• Includes programming software and a user’s manual
• Includes a +5-volt power cable and a DB9 to DB25 connector adapter
® IBM is a registered trademark145 of International Business Machines Corporation.
Development Support
M68HC11E Family Data Sheet, Rev. 5.1
190 Freescale Semiconductor
M68HC11E Family Data Sheet, Rev. 5.1
192 Freescale Semiconductor
EVBU Schematic
Figure B-1. EVBU Schematic Diagram
RXD
←
4
14
MCU 34 34
MCU 33 33
MCU 32 32
MCU 31 31
MCU 30 30
MCU 29 29
MCU 28 28
MCU 27 27
MCU 20 20
MCU 21 21
MCU 22 22
MCU 23 23
MCU 24 24
MCU 25 25
MCU 43 43
MCU 45 45
MCU 47 47
MCU 49 49
MCU 44 44
MCU 46 46
MCU 48 48
MCU 50 50
MCU 52 52
MCU 51 51
1
V
DD
25
PA0/IC3
PA1/IC2
PA2/IC1
PA3/OC5
PA4/OC4
PA5/OC3
PA6/OC2
PA7/OC1
PD0/RXD
PD1/TXD
PD2/MISO
PD3/MOSI
PD4/SCK
PD5/SS
PE0
PE1
PE2
PE3
PE4
PE5
PE6
PE7
V
RH
V
RL
V
SS
C7
1
µ
F
C8
0.1
µ
F
V
CC
MCU43 (PE0)
R4
47 K
2
J2
V
CC
1
3
MCU52 (V
RH
)
R3
1 K
C9
0.1
µ
F
V
CC
GND
NOTE 1
1
U2
V
CC
2
3
INPUT
RESET
GND
MC34064P
V
CC
MCU17 (RESET)
RN1A
47 K
1
2
SW1
Notes:
1. Default cut traces installed from factory on bottom of the board.
2. X1 is shipped as a ceramic resonator with built-in capacitors. Holes are provided for a crystal and two capacitors.
MASTER RESET
MCU21 (PD1/TXD)
MCU20 (PD0/RXD) 12
J9
J8
21
NOTE 1
NOTE 1
V
CC
RN1E
47 K
1
6
PB0/A8
PB1/A9
PB2/A10
PB3/A11
PB4/A12
PB5/A13
PB6/A14
PB7/A15
PC0/AD0
PC1/AD1
PC2/AD2
PC3/AD3
PC4/AD4
PC5/AD5
PC6/AD6
PC7/AD7
E
STRB/R/W
STRA/AS
RESET
IRQ
XIRQ
MODA/LIR
MODB/V
STBY
EXTAL
XTAL R2
10 M
X1
8 MHz
C6
27 pF
C5
27 pF
NOTE 2
5MCU5
6MCU6
4MCU4
17 MCU17
19 MCU19
18 MCU18
3MCU3
2MCU2
42 MCU42
41 MCU41
40 MCU40
39 MCU39
38 MCU38
37 MCU37
36 MCU36
35 MCU35
9MCU9
10 MCU10
11 MCU11
12 MCU12
13 MCU13
14 MCU14
15 MCU15
16 MCU16
7
8
MC68HC11E9FN
U3
MCU18 (XIRQ)
MCU31 (PA3/OC5)
MCU19 (IRQ)
MCU3 (MODA/LIR)
MCU2 (MODB/V
STBY
)
MCU8
MCU7
J6
21
J5
21
2
1
V
CC
1
5
J7
RN1D
47 K
V
CC
1
4
RN1C
47 K
V
CC
1
3
RN1B
47 K
V
CC
R1
47 K
NOTE 1
2
1
J3
J4
2
1
USER’S TERMINAL OR PC
MCU [2 . . . 52]
13
25
12
24
11
23
10
22
9
21
8
20
7
19
6
18
5
17
4
16
3
15
2
1
NC
V
CC
V
CC
C1+
C1–
C2+
C2–
DI1
DI2
DI3
DD1
DD2
DD3
V
CC
MC145407
C11
0.1
µ
F
20
18
1
3
15
16
13
14
11
12
19
V
DD
V
SS
TX1
RX1
TX2
RX2
TX3
RX3
GND
17
6
5
8
7
10
9
2
U4
V
CC
C14
10
µ
F
20 V
21
J15
NOTE 1
DCD
DTR
DSR
CTS
TXD
→
P2
CONNECTOR DB25
+
+
+
+
C10
C12
C13
© Freescale Semiconductor, Inc., 2005. All rights reserved.
Freescale Semiconductor
Application Note
AN1060
Rev. 1.1, 07/2005
M68HC11 Bootstrap Mode
By Jim Sibigtroth
Mike Rhoades
John Langan
Austin, Texas
Introduction
The M68HC11 Family of MCUs (microcontroller units) has a bootstrap mode that allows a user-defined
program to be loaded into the internal random-access memory (RAM) by way of the serial
communications interface (SCI); the M68HC11 then executes this loaded program. The loaded program
can do anything a normal user program can do as well as anything a factory test program can do because
protected control bits are accessible in bootstrap mode. Although the bootstrap mode is a single-chip
mode of operation, expanded mode resources are accessible because the mode control bits can be
changed while operating in the bootstrap mode.
This application note explains the operation and application of the M68HC11 bootstrap mode. Although
basic concepts associated with this mode are quite simple, the more subtle implications of these functions
require careful consideration. Useful applications of this mode are overlooked due to an incomplete
understanding of bootstrap mode. Also, common problems associated with bootstrap mode could be
avoided by a more complete understanding of its operation and implications.
Topics discussed in this application note include:
• Basic operation of the M68HC11 bootstrap mode
• General discussion of bootstrap mode uses
• Detailed explanation of on-chip bootstrap logic
• Detailed explanation of bootstrap firmware
• Bootstrap firmware vs. EEPROM security
• Incorporating the bootstrap mode into a system
• Driving bootstrap mode from another M68HC11
• Driving bootstrap mode from a personal computer
• Common bootstrap mode problems
• Variations for specific versions of M68HC11
• Commented listings for selected M68HC11 bootstrap ROMs
M68HC11 Bootstrap Mode, Rev. 1.1
194 Freescale Semiconductor
Basic Bootstrap Mode
Basic Bootstrap Mode
This section describes only basic functions of the bootstrap mode. Other functions of the bootstrap mode
are described in detail in the remainder of this application note.
When an M68HC11 is reset in bootstrap mode, the reset vector is fetched from a small internal read-only
memory (ROM) called the bootstrap ROM or boot ROM. The firmware program in this boot ROM then
controls the bootloading process, in this manner:
• First, the on-chip SCI (serial communications interface) is initialized. The first character received
($FF) determines which of two possible baud rates should be used for the remaining characters in
the download operation.
• Next, a binary program is received by the SCI system and is stored in RAM.
• Finally, a jump instruction is executed to pass control from the bootloader firmware to the user’s
loaded program.
Bootstrap mode is useful both at the component level and after the MCU has been embedded into a
finished user system.
At the component level, Freescale uses bootstrap mode to control a monitored burn-in program for the
on-chip electrically erasable programmable read-only memory (EEPROM). Units to be tested are loaded
into special circuit boards that each hold many MCUS. These boards are then placed in burn-in ovens.
Driver boards outside the ovens download an EEPROM exercise and diagnostic program to all MCUs in
parallel. The MCUs under test independently exercise their internal EEPROM and monitor programming
and erase operations. This technique could be utilized by an end user to load program information into
the EPROM or EEPROM of an M68HC11 before it is installed into an end product. As in the burn-in setup,
many M68HC11s can be gang programmed in parallel. This technique can also be used to program the
EPROM of finished products after final assembly.
Freescale also uses bootstrap mode for programming target devices on the M68HC11 evaluation
modules (EVM). Because bootstrap mode is a privileged mode like special test, the EEPROM-based
configuration register (CONFIG) can be programmed using bootstrap mode on the EVM.
The greatest benefits from bootstrap mode are realized by designing the finished system so that bootstrap
mode can be used after final assembly. The finished system need not be a single-chip mode application
for the bootstrap mode to be useful because the expansion bus can be enabled after resetting the MCU
in bootstrap mode. Allowing this capability requires almost no hardware or design cost and the addition
of this capability is invisible in the end product until it is needed.
The ability to control the embedded processor through downloaded programs is achieved without the
disassembly and chip-swapping usually associated with such control. This mode provides an easy way
to load non-volatile memories such as EEPROM with calibration tables or to program the application
firmware into a one-time programmable (OTP) MCU after final assembly.
Another powerful use of bootstrap mode in a finished assembly is for final test. Short programs can be
downloaded to check parts of the system, including components and circuitry external to the embedded
MCU. If any problems appear during product development, diagnostic programs can be downloaded to
find the problems, and corrected routines can be downloaded and checked before incorporating them into
the main application program.
Bootstrap Mode Logic
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 195
Bootstrap mode can also be used to interactively calibrate critical analog sensors. Since this calibration
is done in the final assembled system, it can compensate for any errors in discrete interface circuitry and
cabling between the sensor and the analog inputs to the MCU. Note that this calibration routine is a
downloaded program that does not take up space in the normal application program.
Bootstrap Mode Logic
In the M68HC11 MCUs, very little logic is dedicated to the bootstrap mode. Consequently, this mode adds
almost no extra cost to the MCU system. The biggest piece of circuitry for bootstrap mode is the small
boot ROM. This ROM is 192 bytes in the original MC68HC11A8, but some of the newest members of the
M68HC11 Family, such as the MC68HC711K4, have as much as 448 bytes to accommodate added
features. Normally, this boot ROM is present in the memory map only when the MCU is reset in bootstrap
mode to prevent interference with the user’s normal memory space. The enable for this ROM is controlled
by the read boot ROM (RBOOT) control bit in the highest priority interrupt (HPRIO) register. The RBOOT
bit can be written by software whenever the MCU is in special test or special bootstrap modes; when the
MCU is in normal modes, RBOOT reverts to 0 and becomes a read-only bit. All other logic in the MCU
would be present whether or not there was a bootstrap mode.
Figure 1 shows the composite memory map of the MC68HC711E9 in its four basic modes of operation,
including bootstrap mode. The active mode is determined by the mode A (MDA) and special mode
(SMOD) control bits in the HPRIO control register. These control bits are in turn controlled by the state of
the mode A (MODA) and mode B (MODB) pins during reset. Table 1 shows the relationship between the
state of these pins during reset, the selected mode, and the state of the MDA, SMOD, and RBOOT control
bits. Refer to the composite memory map and information in Table 1 for the following discussion.
The MDA control bit is determined by the state of the MODA pin as the MCU leaves reset. MDA selects
between single-chip and expanded operating modes. When MDA is 0, a single-chip mode is selected,
either normal single-chip mode or special bootstrap mode. When MDA is 1, an expanded mode is
selected, either normal expanded mode or special test mode.
The SMOD control bit is determined by the inverted state of the MODB pin as the MCU leaves reset.
SMOD controls whether a normal mode or a special mode is selected. When SMOD is 0, one of the two
normal modes is selected, either normal single-chip mode or normal expanded mode. When SMOD is 1,
one of the two special modes is selected, either special bootstrap mode or special test mode. When either
special mode is in effect (SMOD = 1), certain privileges are in effect, for instance, the ability to write to the
mode control bits and fetching the reset and interrupt vectors from $BFxx rather than $FFxx.
Table 1. Mode Selection Summary
Input Pins Mode Selected Control Bits in HPRIO
MODB MODA RBOOT SMOD MDA
1 0 Normal single chip 0 0 0
0 0 Normal expanded 0 0 1
0 0 Special bootstrap 1 1 0
0 1 Special test 0 1 1
M68HC11 Bootstrap Mode, Rev. 1.1
196 Freescale Semiconductor
Boot ROM Firmware
The alternate vector locations are achieved by simply driving address bit A14 low during all vector fetches
if SMOD = 1. For special test mode, the alternate vector locations assure that the reset vector can be
fetched from external memory space so the test system can control MCU operation. In special bootstrap
mode, the small boot ROM is enabled in the memory map by RBOOT = 1 so the reset vector will be
fetched from this ROM and the bootloader firmware will control MCU operation.
RBOOT is reset to 1 in bootstrap mode to enable the small boot ROM. In the other three modes, RBOOT
is reset to 0 to keep the boot ROM out of the memory map. While in special test mode, SMOD = 1, which
allows the RBOOT control bit to be written to 1 by software to enable the boot ROM for testing purposes.
Boot ROM Firmware
The main program in the boot ROM is the bootloader, which is automatically executed as a result of
resetting the MCU in bootstrap mode. Some newer versions of the M68HC11 Family have additional utility
programs that can be called from a downloaded program. One utility is available to program EPROM or
OTP versions of the M68HC11. A second utility allows the contents of memory locations to be uploaded
to a host computer. In the MC68HC711K4 boot ROM, a section of code is used by Freescale for stress
testing the on-chip EEPROM. These test and utility programs are similar to self-test ROM programs in
other MCUs except that the boot ROM does not use valuable space in the normal memory map.
Bootstrap firmware is also involved in an optional EEPROM security function on some versions of the
M68HC11. This EEPROM security feature prevents a software pirate from seeing what is in the on-chip
EEPROM. The secured state is invoked by programming the no security (NOSEC) EEPROM bit in the
CONFIG register. Once this NOSEC bit is programmed to 0, the MCU will ignore the mode A pin and
always come out of reset in normal single-chip mode or special bootstrap mode, depending on the state
of the mode B pin. Normal single-chip mode is the usual way a secured part would be used. Special
bootstrap mode is used to disengage the security function (only after the contents of EEPROM and RAM
have been erased). Refer to the M68HC11 Reference Manual, Freescale document order number
M68HC11RM/AD, for additional information on the security mode and complete listings of the boot ROMs
that support the EEPROM security functions.
Automatic Selection of Baud Rate
The bootloader program in the MC68HC711E9 accommodates either of two baud rates.
• The higher of these baud rates (7812 baud at a 2-MHz E-clock rate) is used in systems that operate
from a binary frequency crystal such as 223 Hz (8.389 MHz). At this crystal frequency, the baud
rate is 8192 baud, which was used extensively in automotive applications.
• The second baud rate available to the M68HC11 bootloader is 1200 baud at a 2-MHz E-clock rate.
Some of the newest versions of the M68HC11, including the MC68HC11F1 and MC68HC117K4,
accommodate other baud rates using the same differentiation technique explained here. Refer to
the reference numbers in square brackets in Figure 2 during the following explanation.
NOTE
Software can change some aspects of the memory map after reset.
Automatic Selection of Baud Rate
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 197
Figure 2 shows how the bootloader program differentiates between the default baud rate (7812 baud at
a 2-MHz E-clock rate) and the alternate baud rate (1200 baud at a 2-MHz E-clock rate). The host
computer sends an initial $FF character, which is used by the bootloader to determine the baud rate that
will be used for the downloading operation. The top half of Figure 2 shows normal reception of $FF.
Receive data samples at [1] detect the falling edge of the start bit and then verify the start bit by taking a
sample at the center of the start bit time. Samples are then taken at the middle of each bit time [2] to
reconstruct the value of the received character (all 1s in this case). A sample is then taken at the middle
of the stop bit time as a framing check (a 1 is expected) [3]. Unless another character immediately follows
this $FF character, the receive data line will idle in the high state as shown at [4].
The bottom half of Figure 2 shows how the receiver will incorrectly receive the $FF character that is sent
from the host at 1200 baud. Because the receiver is set to 7812 baud, the receive data samples are taken
at the same times as in the upper half of Figure 2. The start bit at 1200 baud [5] is 6.5 times as long as
the start bit at 7812 baud [6].
Figure 1. MC68HC711E9 Composite Memory Map
$0000
512-BYTE
RAM
$01FF
$1000
$103F
$B600
$B7FF
$BF00
$BFFF
$FFFF
$BFC0
$FFC0
SINGLE
CHIP
EXPANDED
MULTIPLEXED
EXTERNAL
EXTERNAL
SPECIAL
BOOTSTRAP
SPECIAL
TEST
EXTERNAL
EXTERNAL
EXTERNAL
64-BYTE
REGISTER
BLOCK
512-BYTE
EEPROM
BOOT
ROM
12K USER
EPROM
(or OTP)
(MAY BE REMAPPED
TO ANY 4K BOUNDARY)
(MAY BE REMAPPED
TO ANY 4K BOUNDARY)
(MAY BE DISABLED
BY AN EEPROM BIT)
(MAY BE DISABLED
BY AN EEPROM BIT)
SPECIAL
MODE
VECTORS
NORMAL
MODE
VECTORS
$BFC0
$BFFF
$FFC0
$FFFF
MODA = 0
MODB = 1
MODA = 1
MODB = 1
MODA = 0
MODB = 0
MODA = 1
MODB = 0
EXTERNAL
NOTE: Software can chan
g
e some as
p
ects of the memor
y
ma
p
after reset.
$D000
M68HC11 Bootstrap Mode, Rev. 1.1
198 Freescale Semiconductor
Main Bootloader Program
Figure 2. Automatic Detection of Baud Rate
Samples taken at [7] detect the failing edge of the start bit and verify it is a logic 0. Samples taken at the
middle of what the receiver interprets as the first five bit times [8] detect logic 0s. The sample taken at the
middle of what the receiver interprets as bit 5 [9] may detect either a 0 or a 1 because the receive data
has a rising transition at about this time. The samples for bits 6 and 7 detect 1s, causing the receiver to
think the received character was $C0 or $E0 [10] at 7812 baud instead of the $FF which was sent at 1200
baud. The stop bit sample detects a 1 as expected [11], but this detection is actually in the middle of bit
0 of the 1200 baud $FF character. The SCI receiver is not confused by the rest of the 1200 baud $FF
character because the receive data line is high [12] just as it would be for the idle condition. If a character
other than $FF is sent as the first character, an SCI receive error could result.
Main Bootloader Program
Figure 3 is a flowchart of the main bootloader program in the MC68HC711E9. This bootloader
demonstrates the most important features of the bootloaders used on all M68HC11 Family members. For
complete listings of other M68HC11 versions, refer to Listing 3. MC68HC711E9 Bootloader ROM at the
end of this application note, and to Appendix B of the M68HC11 Reference Manual, Freescale document
order number M68HC11RM/AD.
The reset vector in the boot ROM points to the start [1] of this program. The initialization block [2]
establishes starting conditions and sets up the SCI and port D. The stack pointer is set because there are
push and pull instructions in the bootloader program. The X index register is pointed at the start of the
register block ($1000) so indexed addressing can be used. Indexed addressing takes one less byte of
ROM space than extended instructions, and bit manipulation instructions are not available in extended
addressing forms. The port D wire-OR mode (DWOM) bit in the serial peripheral interface control register
(SPCR) is set to configure port D for wired-OR operation to minimize potential conflicts with external
systems that use the PD1/TxD pin as an input. The baud rate for the SCI is initially set to 7812 baud at a
2-MHz E-clock rate but can automatically switch to 1200 baud based on the first character received. The
SCI receiver and transmitter are enabled. The receiver is required by the bootloading process, and the
transmitter is used to transmit data back to the host computer for optional verification. The last item in the
initialization is to set an intercharacter delay constant used to terminate the download when the host
computer stops sending data to the MC68HC711E9. This delay constant is stored in the timer output
compare 1 (TOC1) register, but the on-chip timer is not used in the bootloader program. This example
START
$FF CHARACTER
@ 7812 BAUD
[6]
BIT 0 BIT 1 BIT 2 BIT 3 BIT 4 BIT 5 BIT 7BIT 6 STOP Tx DATA LINE IDLES HIGH
START
$FF CHARACTER
@ 1200 BAUD BIT 0 BIT 1
01S 11111111
Rx DATA SAMPLES
00S 0000?111
Rx DATA SAMPLES
( FOR 7812 BAUD )
$FF
$C0
or $E0
[12]
[1] [2]
[3]
[4]
[5]
[7] [9]
[
10
]
[11]
[8]
Main Bootloader Program
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 199
illustrates the extreme measures used in the bootloader firmware to minimize memory usage. However,
such measures are not usually considered good programming technique because they are misleading to
someone trying to understand the program or use it as an example.
After initialization, a break character is transmitted [3] by the SCI. By connecting the TxD pin to the RxD
pin (with a pullup because of port D wired-OR mode), this break will be received as a $00 character and
cause an immediate jump [4] to the start of the on-chip EEPROM ($B600 in the MC68HC711E9). This
feature is useful to pass control to a program in EEPROM essentially from reset. Refer to Common
Bootstrap Mode Problems before using this feature.
If the first character is received as $FF, the baud rate is assumed to be the default rate (7812 baud at a
2-MHz E-clock rate). If $FF was sent at 1200 baud by the host, the SCI will receive the character as $E0
or $C0 because of the baud rate mismatch, and the bootloader will switch to 1200 baud [5] for the rest of
the download operation. When the baud rate is switched to 1200 baud, the delay constant used to monitor
the intercharacter delay also must be changed to reflect the new character time.
At [6], the Y index register is initialized to $0000 to point to the start of on-chip RAM. The index register Y
is used to keep track of where the next received data byte will be stored in RAM. The main loop for loading
begins at [7].
The number of data bytes in the downloaded program can be any number between 0 and 512 bytes (the
size of on-chip RAM). This procedure is called "variable-length download" and is accomplished by ending
the download sequence when an idle time of at least four character times occurs after the last character
to be downloaded. In M68HC11 Family members which have 256 bytes of RAM, the download length is
fixed at exactly 256 bytes plus the leading $FF character.
The intercharacter delay counter is started [8] by loading the delay constant from TOC1 into the X index
register. The 19-E-cycle wait loop is executed repeatedly until either a character is received [9] or the
allowed intercharacter delay time expires [10]. For 7812 baud, the delay constant is 10,241 E cycles (539
x 19 E cycles per loop). Four character times at 7812 baud is 10,240 E cycles (baud prescale of 4 x baud
divider of 4 x 16 internal SCI clocks/bit time x 10 bit times/character x 4 character times). The delay from
reset to the initial $FF character is not critical since the delay counter is not started until after the first
character ($FF) is received.
To terminate the bootloading sequence and jump to the start of RAM without downloading any data to the
on-chip RAM, simply send $FF and nothing else. This feature is similar to the jump to EEPROM at [4]
except the $FF causes a jump to the start of RAM. This procedure requires that the RAM has been loaded
with a valid program since it would make no sense to jump to a location in uninitialized memory.
After receiving a character, the downloaded byte is stored in RAM [11]. The data is transmitted back to
the host [12] as an indication that the download is progressing normally. At [13], the RAM pointer is
incremented to the next RAM address. If the RAM pointer has not passed the end of RAM, the main
download loop (from [7] to [14]) is repeated.
When all data has been downloaded, the bootloader goes to [16] because of an intercharacter delay
timeout [10] or because the entire 512-byte RAM has been filled [15]. At [16], the X and Y index registers
are set up for calling the PROGRAM utility routine, which saves the user from having to do this in a
downloaded program. The PROGRAM utility is fully explained in EPROM Programming Utility. The final
step of the bootloader program is to jump to the start of RAM [17], which starts the user’s downloaded
program.
M68HC11 Bootstrap Mode, Rev. 1.1
200 Freescale Semiconductor
Main Bootloader Program
Figure 3. MC68HC711E9 Bootloader Flowchart
RECEIVE DATA READY ?
INITIALIZATION:
SP = TOP OF RAM ($01FF)
X = START OF REGS ($1000)
SPCR = $20 (SET DWOM BIT)
BAUD = $A2 (÷ 4; ÷ 4) (7812.5 BAUD @ 2 MHz)
SCCR2 = $C0 (Tx & Rx ON)
TOC1 = DELAY CONSTANT (539 = 4 SCI CHARACTER TIMES)
START FROM RESET
IN BOOT MODE
SEND BREAK
RECEIVED FIRST CHAR YET ?
NO
YES
FIRST CHAR = $00 ?
NO
YES JUMP TO START
OF EEPROM ($B600)
NOTZERO
FIRST CHAR = $FF ?
NO
YES
BAUDOK
SWITCH TO SLOWER SCI RATE...
BAUD = $33 (÷13; ÷ 8) (1200 BAUD @ 2 MHz)
CHANGE DELAY CONSTANT...
TOC1 = 3504 (4 SCI CHARACTER TIMES)
NOTE THAT A BREAK
CHARACTER IS ALSO
RECEIVED AS $00
POINT TO START OF RAM ( Y = $0000 )
INITIALIZE TIMEOUT COUNT
STORE RECEIVED DATA TO RAM ( ,Y )
TRANSMIT (ECHO) FOR VERIFY
POINT AT NEXT RAM LOCATION
SET UP FOR PROGRAM UTILITY:
X = PROGRAMMING TIME CONSTANT
Y = START OF EPROM
JUMP TO START
OF RAM ($0000)
WAIT
NO
YES
WTLOOP
DECREMENT TIMEOUT COUNT
TIMED OUT YET ?
NO
YES
PAST END OF RAM ? NO
YES
STAR
LOOP =
19
CYCLES
[1]
[2]
[3]
[4]
[5]
[6]
[7]
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[16]
[17]
UPLOAD Utility
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 201
UPLOAD Utility
The UPLOAD utility subroutine transfers data from the MCU to a host computer system over the SCI serial
data link.
NOTE
Only EPROM versions of the M68HC11 include this utility.
Verification of EPROM contents is one example of how the UPLOAD utility could be used. Before calling
this program, the Y index register is loaded (by user firmware) with the address of the first data byte to be
uploaded. If a baud rate other than the current SCI baud rate is to be used for the upload process, the
user’s firmware must also write to the baud register. The UPLOAD program sends successive bytes of
data out the SCI transmitter until a reset is issued (the upload loop is infinite).
For a complete commented listing example of the UPLOAD utility, refer to Listing 3. MC68HC711E9
Bootloader ROM.
EPROM Programming Utility
The EPROM programming utility is one way of programming data into the internal EPROM of the
MC68HC711E9 MCU. An external 12-V programming power supply is required to program on-chip
EPROM. The simplest way to use this utility program is to bootload a 3-byte program consisting of a single
jump instruction to the start of the PROGRAM utility program ($BF00). The bootloader program sets the
X and Y index registers to default values before jumping to the downloaded program (see [16] at the
bottom of Figure 3). When the host computer sees the $FF character, data to be programmed into the
EPROM is sent, starting with the character for location $D000. After the last byte to be programmed is
sent to the MC68HC711E9 and the corresponding verification data is returned to the host, the
programming operation is terminated by resetting the MCU.
The number of bytes to be programmed, the first address to be programmed, and the programming time
can be controlled by the user if values other than the default values are desired.
To understand the detailed operation of the EPROM programming utility, refer to Figure 4 during the
following discussion. Figure 4 is composed of three interrelated parts. The upper-left portion shows the
flowchart of the PROGRAM utility running in the boot ROM of the MCU. The upper-right portion shows
the flowchart for the user-supplied driver program running in the host computer. The lower portion of
Figure 4 is a timing sequence showing the relationship of operations between the MCU and the host
computer. Reference numbers in the flowcharts in the upper half of Figure 4 have matching numbers in
the lower half to help the reader relate the three parts of the figure.
The shaded area [1] refers to the software and hardware latency in the MCU leading to the transmission
of a character (in this case, the $FF). The shaded area [2] refers to a similar latency in the host computer
(in this case, leading to the transmission of the first data character to the MCU).
The overall operation begins when the MCU sends the first character ($FF) to the host computer,
indicating that it is ready for the first data character. The host computer sends the first data byte [3] and
enters its main loop. The second data character is sent [4], and the host then waits [5] for the first verify
byte to come back from the MCU.
M68HC11 Bootstrap Mode, Rev. 1.1
202 Freescale Semiconductor
EPROM Programming Utility
Figure 4. Host and MCU Activity during EPROM PROGRAM Utility
D1
$FF
P1
D2
V1
P2
V2
D3
P3
D4
V3
P4
V4
D5
EPROM PROGRAMMING
MCU RECEIVE DATA (FROM HOST)
MCU TRANSMIT DATA (VERIFY)
$FF
V1
V2
V3
V4
VERIFY DATA TO HOST
(SAME AS MCU Tx DATA)
MC68HC711E9
EXECUTING
"PROGRAM" LOOP
HOST SENDING
DATA FOR
MCU EPROM
[3]
[4] [5]
[6]
[1]
[2]
[7]
[8]
[9]
[10]
[11] [12]
[13]
[14] [15]
SEND $FF
START
INITIALIZE...
X = PROGRAM TIME
Y = FIRST ADDRESS
$BF00 - PROGRAM
WAIT1
ANY DATA RECEIVED ?
NO
YES
PROGRAM BYTE
READ PROGRAMMED DATA
AND SEND TO VERIFY
POINT TO NEXT LOCATION
TO BE PROGRAMMED
INDICATES READY
TO HOST SEND FIRST DATA BYTE
START
HOST NORMALLY WAITS FOR $FF
FROM MCU BEFORE SENDING DATA
FOR EPROM PROGRAMMING
DATA_LOOP
MORE DATA TO SEND ?
NO
YES
SEND NEXT DATA
INDICATE ERROR
VERIFY DATA RECEIVED ?
NO
YES
VERIFY DATA CORRECT ? NO
YES
MORE TO VERIFY ?
NO
YES
DONE
PROGRAM CONTINUES
AS LONG AS DATA
IS RECEIVED
[8]
[9]
[10]
[11]
[12]
[13]
[14]
[15]
[3]
[4]
[5]
[6]
[7]
PROGRAM Utility in MCU Driver Program in HOST
Allowing for Bootstrap Mode
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 203
After the MCU sends $FF [8], it enters the WAIT1 loop [9] and waits for the first data character from the
host. When this character is received [10], the MCU programs it into the address pointed to by the Y index
register. When the programming time delay is over, the MCU reads the programmed data, transmits it to
the host for verification [11], and returns to the top of the WAIT1 loop to wait for the next data character
[12]. Because the host previously sent the second data character, it is already waiting in the SCI receiver
of the MCU. Steps [13], [14], and [15] correspond to the second pass through the WAIT1 loop.
Back in the host, the first verify character is received, and the third data character is sent [6]. The host
then waits for the second verify character [7] to come back from the MCU. The sequence continues as
long as the host continues to send data to the MCU. Since the WAIT1 loop in the PROGRAM utility is an
indefinite loop, reset is used to end the process in the MCU after the host has finished sending data to be
programmed.
Allowing for Bootstrap Mode
Since bootstrap mode requires few connections to the MCU, it is easy to design systems that
accommodate bootstrap mode.
Bootstrap mode is useful for diagnosing or repairing systems that have failed due to changes in the
CONFIG register or failures of the expansion address/data buses, (rendering programs in external
memory useless). Bootstrap mode can also be used to load information into the EPROM or EEPROM of
an M68HC11 after final assembly of a module. Bootstrap mode is also useful for performing system
checks and calibration routines. The following paragraphs explain system requirements for use of
bootstrap mode in a product.
Mode Select Pins
It must be possible to force the MODA and MODB pins to logic 0, which implies that these two pins should
be pulled up to VDD through resistors rather than being tied directly to VDD. If mode pins are connected
directly to VDD, it is not possible to force a mode other than the one the MCU is hard wired for. It is also
good practice to use pulldown resistors to VSS rather than connecting mode pins directly to VSS because
it is sometimes a useful debug aid to attempt reset in modes other than the one the system was primarily
designed for. Physically, this requirement sometimes calls for the addition of a test point or a wire
connected to one or both mode pins. Mode selection only uses the mode pins while RESET is active.
RESET
It must be possible to initiate a reset while the mode select pins are held low. In systems where there is
no provision for manual reset, it is usually possible to generate a reset by turning power off and back on.
RxD Pin
It must be possible to drive the PD0/RxD pin with serial data from a host computer (or another MCU). In
many systems, this pin is already used for SCI communications; thus no changes are required.
M68HC11 Bootstrap Mode, Rev. 1.1
204 Freescale Semiconductor
Allowing for Bootstrap Mode
In systems where the PD0/RxD pin is normally used as a general-purpose output, a serial signal from the
host can be connected to the pin without resulting in output driver conflicts. It may be important to consider
what the existing logic will do with the SCI serial data instead of the signals that would have been
produced by the PD0 pin. In systems where the PD0 pin is used normally as a general-purpose input, the
driver circuit that drives the PD0 pin must be designed so that the serial data can override this driver, or
the driver must be disconnected during the bootstrap download. A simple series resistor between the
driver and the PD0 pin solves this problem as shown in Figure 5. The serial data from the host computer
can then be connected to the PD0/RxD pin, and the series resistor will prevent direct conflict between the
host driver and the normal PD0 driver.
Figure 5. Preventing Driver Conflict
TxD Pin
The bootloader program uses the PD1/TxD pin to send verification data back to the host computer. To
minimize the possibility of conflicts with circuitry connected to this pin, port D is configured for wire-OR
mode by the bootloader program during initialization. Since the wire-OR configuration prevents the pin
from driving active high levels, a pullup resistor to VDD is needed if the TxD signal is used.
In systems where the PD1/TxD pin is normally used as a general-purpose output, there are no output
driver conflicts. It may be important to consider what the existing logic will do with the SCI serial data
instead of the signals that would have been produced by the PD1 pin.
In systems where the PD1 pin is normally used as a general-purpose input, the driver circuit that drives
the PD1 pin must be designed so that the PD1/TxD pin driver in the MCU can override this driver. A simple
series resistor between the driver and the PD1 pin can solve this problem. The TxD pin can then be
configured as an output, and the series resistor will prevent direct conflict between the internal TxD driver
and the external driver connected to PD1 through the series resistor.
Other
The bootloader firmware sets the DWOM control bit, which configures all port D pins for wire-OR
operation. During the bootloading process, all port D pins except the PD1/TxD pin are configured as
high-impedance inputs. Any port D pin that normally is used as an output should have a pullup resistor so
it does not float during the bootloading process.
RxD/PD0
(BEING USED
AS INPUT)
EXISTING
CONTROL
SIGNAL SERIES
RESISTOR
RS232
LEVEL
SHIFTER
FROM
HOST
SYSTEM
MC68HC11
EXISTING
DRIVER
CONNECTED ONLY DURING
BOOTLOADING
Driving Boot Mode from Another M68HC11
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 205
Driving Boot Mode from Another M68HC11
A second M68HC11 system can easily act as the host to drive bootstrap loading of an M68HC11 MCU.
This method is used to examine and program non-volatile memories in target M68HC11s in Freescale
EVMs. The following hardware and software example will demonstrate this and other bootstrap mode
features.
The schematic in Figure 6 shows the circuitry for a simple EPROM duplicator for the MC68HC711E9. The
circuitry is built in the wire-wrap area of an M68HC11EVBU evaluation board to simplify construction. The
schematic shows only the important portions of the EVBU circuitry to avoid confusion. To see the
complete EVBU schematic, refer to the M68HC11EVBU Universal Evaluation Board User’s Manual,
Freescale document order number M68HC11EVBU/D.
The default configuration of the EVBU must be changed to make the appropriate connections to the
circuitry in the wire-wrap area and to configure the master MCU for bootstrap mode. A fabricated jumper
must be installed at J6 to connect the XTAL output of the master MCU to the wire-wrap connector P5,
which has been wired to the EXTAL input of the target MCU. Cut traces that short across J8 and J9 must
be cut on the solder side of the printed circuit board to disconnect the normal SCI connections to the
RS232 level translator (U4) of the EVBU. The J8 and J9 connections can be restored easily at a later time
by installing fabricated jumpers on the component side of the board. A fabricated jumper must be installed
across J3 to configure the master MCU for bootstrap mode.
One MC68HC711E9 is first programmed by other means with a desired 12-Kbyte program in its EPROM
and a small duplicator program in its EEPROM. Alternately, the ROM program in an MC68HC11E9 can
be copied into the EPROM of a target MC68HC711E9 by programming only the duplicator program into
the EEPROM of the master MC68HC11E9. The master MCU is installed in the EVBU at socket U3. A
blank MC68HC711E9 to be programmed is placed in the socket in the wire-wrap area of the EVBU (U6).
With the VPP power switch off, power is applied to the EVBU system. As power is applied to the EVBU,
the master MCU (U3) comes out of reset in bootstrap mode. Target MCU (U6) is held in reset by the PB7
output of master MCU (U3). The PB7 output of U3 is forced to 0 when U3 is reset. The master MCU will
later release the reset signal to the target MCU under software control. The RxD and TxD pins of the target
MCU (U6) are high-impedance inputs while U6 is in reset so they will not affect the TxD and RxD signals
of the master MCU (U3) while U3 is coming out of reset. Since the target MCU is being held in reset with
MODA and MODB at 0, it is configured for the PROG EPROM emulation mode, and PB7 is the output
enable signal for the EPROM data I/O (input/output) pins. Pullup resistor R7 causes the port D pins,
including RxD and TxD, to remain in the high-impedance state so they do not interfere with the RxD and
TxD pins of the master MCU as it comes out of reset.
As U3 leaves reset, its mode pins select bootstrap mode so the bootloader firmware begins executing. A
break is sent out the TxD pin of U3. Pullup resistor R10 and resistor R9 cause the break character to be
seen at the RxD pin of U3. The bootloader performs a jump to the start of EEPROM in the master MCU
(U3) and starts executing the duplicator program. This sequence demonstrates how to use bootstrap
mode to pass control to the start of EEPROM after reset.
The complete listing for the duplicator program in the EEPROM of the master MCU is provided in
Listing 1. MCU-to-MCU Duplicator Program.
M68HC11 Bootstrap Mode, Rev. 1.1
206 Freescale Semiconductor
Driving Boot Mode from Another M68HC11
Figure 6. MCU-to-MCU EPROM Duplicator Schematic
100
R11
OFF
ON
VPP
S2
+
C18
20 µ F
R14
15K
R15
10K
1KR12 RED
D5
1KR13 GREEN
D6
VDD
C17
0.1 µ F
3.3K
R8
J8 J9
R10
15K
R9
10K
VDD VDD
10K
R7
PB7
RxD
EXTAL
TxD
MODA
MODB
VDD
VSS
XIRQ/V PPE
RESET
MC68HC711E9
TARGET
MCU
U6
J6
J3
TO/FROM
RS232 LEVEL
TRANSLATOR
U4
PB7
RxD
XTAL
TxD
MODB
PB0
PB1
PE7
17
21
7
20
1
26
35
20
8
21
42
41
50
18
35
3
2
35
20
8
21
42
41
50
+12.25VCOM
P5P4
WIRE-WRAP AREA
M68HC11EVBU
PREWIRED AREA
35
20
8
21
42
41
50
2
MASTER
MCU
U3
[1]
[2]
Driving Boot Mode from Another M68HC11
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 207
The duplicator program in EEPROM clears the DWOM control bit to change port D (thus, TxD) of U3 to
normal driven outputs. This configuration will prevent interference due to R9 when TxD from the target
MCU (U6) becomes active. Series resistor R9 demonstrates how TxD of U3 can drive RxD of U3[1] and
later TxD of U6 can drive RxD of U3 without a destructive conflict between the TxD output buffers.
As the target MCU (U6) leaves reset, its mode pins select bootstrap mode so the bootloader firmware
begins executing. A break is sent out the TxD pin of U6. At this time, the TxD pin of U3 is at a driven high
so R9 acts as a pullup resistor for TxD of the target MCU (U6). The break character sent from U6 is
received by U3 so the duplicator program that is running in the EEPROM of the master MCU knows that
the target MCU is ready to accept a bootloaded program.
The master MCU sends a leading $FF character to set the baud rate in the target MCU. Next, the master
MCU passes a 3-instruction program to the target MCU and pauses so the bootstrap program in the target
MCU will stop the loading process and jump to the start of the downloaded program. This sequence
demonstrates the variable-length download feature of the MC68HC711E9 bootloader.
The short program downloaded to the target MCU clears the DWOM bit to change its TxD pin to a normal
driven CMOS output and jumps to the EPROM programming utility in the bootstrap ROM of the target
MCU.
Note that the small downloaded program did not have to set up the SCI or initialize any parameters for
the EPROM programming process. The bootstrap software that ran prior to the loaded program left the
SCI turned on and configured in a way that was compatible with the SCI in the master MCU (the duplicator
program in the master MCU also did not have to set up the SCI for the same reason). The programming
time and starting address for EPROM programming in the target MCU were also set to default values by
the bootloader software before jumping to the start of the downloaded program.
Before the EPROM in the target MCU can be programmed, the VPP power supply must be available at
the XIRQ/VPPE pin of the target MCU. The duplicator program running in the master MCU monitors this
voltage (for presence or absence, not level) at PE7 through resistor divider R14–Rl5. The PE7 input was
chosen because the internal circuitry for port E pins can tolerate voltages slightly higher than VDD;
therefore, resistors R14 and R15 are less critical. No data to be programmed is passed to the target MCU
until the master MCU senses that VPP has been stable for about 200 ms.
When VPP is ready, the master MCU turns on the red LED (light-emitting diode) and begins passing data
to the target MCU. EPROM Programming Utility explains the activity as data is sent from the master MCU
to the target MCU and programmed into the EPROM of the target. The master MCU in the EVBU
corresponds to the HOST in the programming utility description and the "PROGRAM utility in MCU" is
running in the bootstrap ROM of the target MCU.
Each byte of data sent to the target is programmed and then the programmed location is read and sent
back to the master for verification. If any byte fails, the red and green LEDs are turned off, and the
programming operation is aborted. If the entire 12 Kbytes are programmed and verified successfully, the
red LED is turned off, and the green LED is turned on to indicate success. The programming of all 12
Kbytes takes about 30 seconds.
After a programming operation, the VPP switch (S2) should be turned off before the EVBU power is turned
off.
M68HC11 Bootstrap Mode, Rev. 1.1
208 Freescale Semiconductor
Listing 1. MCU-to-MCU Duplicator Program
Figure 7. Isolating EVBU XIRQ Pin
Listing 1. MCU-to-MCU Duplicator Program
1 **************************************************
2 * 68HC711E9 Duplicator Program for AN1060
3 **************************************************
4
5 *****
6 * Equates - All reg addrs except INIT are 2-digit
7 * for direct addressing
8 *****
9 103D INIT EQU $103D RAM, Reg mapping
10 0028 SPCR EQU $28 DWOM in bit-5
11 0004 PORTB EQU $04 Red LED = bit-1, Grn = bit-0
12 * Reset of prog socket = bit-7
13 0080 RESET EQU %10000000
14 0002 RED EQU %00000010
15 0001 GREEN EQU %00000001
16 000A PORTE EQU $0A Vpp Sense in bit-7, 1=ON
17 002E SCSR EQU $2E SCI status register
18 * TDRE, TC, RDRF, IDLE; OR, NF, FE, -
19 0080 TDRE EQU %10000000
20 0020 RDRF EQU %00100000
21 002F SCDR EQU $2F SCI data register
22 BF00 PROGRAM EQU $BF00 EPROM prog utility in boot ROM
23 D000 EPSTRT EQU $D000 Starting address of EPROM
24
25 B600 ORG $B600 Start of EEPROM
26
25
13
1
1
1
3+
9
8
10
20
21
19
15
7
1
2
45
48 47
46
44
41
38
34
35 33 27
28
42 50
CUT TRACE
AS SHOWN
RN1D
47K
VDD
J14
J7
TO
MC68HC68T1
REMOVE J7
JUMPER
BE SURE NO
JUMPER IS
ON J14
FROM OC5 PIN
OF MCU
TO MCU
X I R Q / V
PIN PPE
P4-18
P5-18
TO MCU
XIRQ/VPPE
PIN
Listing 1. MCU-to-MCU Duplicator Program
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 209
27 **************************************************
28 *
29 B600 7F103D BEGIN CLR INIT Moves Registers to $0000-3F
30 B603 8604 LDAA #$04 Pattern for DWOM off, no SPI
31 B605 9728 STAA SPCR Turns off DWOM in EVBU MCU
32 B607 8680 LDAA #RESET
33 B609 9704 STAA PORTB Release reset to target MCU
34 B60B 132E20FC WT4BRK BRCLR SCSR RDRF WT4BRK Loop till char received
35 B60F 86FF LDAA #$FF Leading char for bootload ...
36 B611 972F STAA SCDR to target MCU
37 B613 CEB675 LDX #BLPROG Point at program for target
38 B616 8D53 BLLOOP BSR SEND1 Bootload to target
39 B618 8CB67D CPX #ENDBPR Past end ?
40 B61B 26F9 BNE BLLOOP Continue till all sent
41 *****
42 * Delay for about 4 char times to allow boot related
43 * SCI communications to finish before clearing
44 * Rx related flags
45 B61D CE06A7 LDX #1703 # of 6 cyc loops
46 B620 09 DLYLP DEX [3]
47 B621 26FD BNE DLYLP [3] Total loop time = 6 cyc
48 B623 962E LDAA SCSR Read status (RDRF will be set)
49 B625 962F LDAA SCDR Read SCI data reg to clear RDRF
50 *****
51 * Now wait for character from target to indicate it's ready for
52 * data to be programmed into EPROM
53 B627 132E20FC WT4FF BRCLR SCSR RDRF WT4FF Wait for RDRF
54 B62B 962F LDAA SCDR Clear RDRF, don't need data
55 B62D CED000 LDX #EPSTRT Point at start of EPROM
56 * Handle turn-on of Vpp
57 B630 18CE523D WT4VPP LDY #21053 Delay counter (about 200ms)
58 B634 150402 BCLR PORTB RED Turn off RED LED
59 B637 960A DLYLP2 LDAA PORTE [3] Wait for Vpp to be ON
60 B639 2AF5 BPL WT4VPP [3] Vpp sense is on port E MSB
61 B63B 140402 BSET PORTB RED [6] Turn on RED LED
62 B63E 1809 DEY [4]
63 B640 26F5 BNE DLYLP2 [3] Total loop time = 19 cyc
64 * Vpp has been stable for 200ms
65
66 B642 18CED000 LDY #EPSTRT X=Tx pointer, Y=verify pointer
67 B646 8D23 BSR SEND1 Send first data to target
68 B648 8C0000 DATALP CPX #0 X points at $0000 after last
69 B64B 2702 BEQ VERF Skip send if no more
70 B64D 8D1C BSR SEND1 Send another data char
71 B64F 132E20FC VERF BRCLR SCSR RDRF VERF Wait for Rx ready
72 B653 962F LDAA SCDR Get char and clr RDRF
73 B655 18A100 CMPA 0,Y Does char verify ?
74 B658 2705 BEQ VERFOK Skip error if OK
75 B65A 150403 BCLR PORTB (RED+GREEN) Turn off LEDs
76 B65D 2007 BRA DUNPRG Done (programming failed)
77 B65F
78 B65F 1808 VERFOK INY Advance verify pointer
79 B661 26E5 BNE DATALP Continue till all done
80 B663
81 B663 140401 BSET PORTB GREEN Grn LED ON
M68HC11 Bootstrap Mode, Rev. 1.1
210 Freescale Semiconductor
Listing 1. MCU-to-MCU Duplicator Program
82 B666
83 B666 150482 DUNPRG BCLR PORTB (RESET+RED) Red OFF, apply reset
84 B669 20FE BRA * Done so just hang
85 B66B
86 **************************************************
87 * Subroutine to get & send an SCI char. Also
88 * advances pointer (X).
89 **************************************************
90 B66B A600 SEND1 LDAA 0,X Get a character
91 B66D 132E80FC TRDYLP BRCLR SCSR TDRE TRDYLP Wait for TDRE
92 B671 972F STAA SCDR Send character
93 B673 08 INX Advance pointer
94 B674 39 RTS ** Return **
95
96 **************************************************
97 * Program to be bootloaded to target '711E9
98 **************************************************
99 B675 8604 BLPROG LDAA #$04 Pattern for DWOM off, no SPI
100 B677 B71028 STAA $1028 Turns off DWOM in target MCU
101 * NOTE: Can't use direct addressing in target MCU because
102 * regs are located at $1000.
103 B67A 7EBF00 JMP PROGRAM Jumps to EPROM prog routine
104 B67D ENDBPR EQU *
Symbol Table:
Symbol Name Value Def.# Line Number Cross Reference
BEGIN B600 *00029
BLLOOP B616 *00038 00040
BLPROG B675 *00099 00037
DATALP B648 *00068 00079
DLYLP B620 *00046 00047
DLYLP2 B637 *00059 00063
DUNPRG B666 *00083 00076
ENDBPR B67D *00104 00039
EPSTRT D000 *00023 00055 00066
GREEN 0001 *00015 00075 00081
INIT 103D *00009 00029
PORTB 0004 *00011 00033 00058 00061 00075 00081 00083
PORTE 000A *00016 00059
PROGRAM BF00 *00022 00103
RDRF 0020 *00020 00034 00053 00071
RED 0002 *00014 00058 00061 00075 00083
RESET 0080 *00013 00032 00083
SCDR 002F *00021 00036 00049 00054 00072 00092
SCSR 002E *00017 00034 00048 00053 00071 00091
SEND1 B66B *00090 00038 00067 00070
SPCR 0028 *00010 00031
TDRE 0080 *00019 00091
TRDYLP B66D *00091 00091
VERF B64F *00071 00069 00071
VERFOK B65F *00078 00074
WT4BRK B60B *00034 00034
WT4FF B627 *00053 00053
WT4VPP B630 *00057 00060
Driving Boot Mode from a Personal Computer
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 211
Errors: None
Labels: 28
Last Program Address: $B67C
Last Storage Address: $0000
Program Bytes: $007D 125
Storage Bytes: $0000 0
Driving Boot Mode from a Personal Computer
In this example, a personal computer is used as the host to drive the bootloader of an MC68HC711E9.
An M68HC11 EVBU is used for the target MC68HC711E9. A large program is transferred from the
personal computer into the EPROM of the target MC68HC711E9.
Hardware
Figure 7 shows a small modification to the EVBU to accommodate the 12-volt (nominal) EPROM
programming voltage. The XIRQ pin is connected to a pullup resistor, two jumpers, and the 60-pin
connectors, P4 and P5. The object of the modification is to isolate the XIRQ pin and then connect it to the
programming power supply. Carefully cut the trace on the solder side of the EVBU as indicated in Figure
7. This disconnects the pullup resistor RN1 D from XIRQ but leaves P4–18, P5–18, and jumpers J7 and
J14 connected so the EVBU can still be used for other purposes after programming is done. Remove any
fabricated jumpers from J7 and J14. The EVBU normally has a jumper at J7 to support the trace function
Figure 8 shows a small circuit that is added to the wire-wrap area of the EVBU. The 3-terminal jumper
allows the XIRQ line to be connected to either the programming power supply or to a substitute pullup
resistor for XIRQ. The 100-ohm resistor is a current limiter to protect the 12-volt input of the MCU. The
resistor and LED connected to P5 pin 9 (port C bit 0) is an optional indicator that lights when programming
is complete.
Software
BASIC was chosen as the programming language due to its readability and availability in parallel versions
on both the IBM® PC and the Macintosh®. The program demonstrates several programming techniques
for use with an M68HC11 and is not necessarily intended to be a finished, commercial program. For
example, there is little error checking, and the user interface is elementary. A complete listing of the
BASIC program is included in Listing 2. BASIC Program for Personal Computer with moderate comments.
The following paragraphs include a more detailed discussion of the program as it pertains to
communicating with and programming the target MC68HC711E9. Lines 25–45 initialize and define the
variables and array used in the program. Changes to this section would allow for other programs to be
downloaded.
® IBM is a registered trademark of International Business Machines.
® Macintosh is a registered trademark of Apple Computers, Inc.
M68HC11 Bootstrap Mode, Rev. 1.1
212 Freescale Semiconductor
Driving Boot Mode from a Personal Computer
Figure 8. PC-to-MCU Programming Circuit
Lines 50–95 read in the small bootloader from DATA statements at the end of the listing. The source code
for this bootloader is presented in the DATA statements. The bootloaded code makes port C bit 0 low,
initializes the X and Y registers for use by the EPROM programming utility routine contained in the boot
ROM, and then jumps to that routine. The hexadecimal values read in from the DATA statements are
converted to binary values by a subroutine. The binary values are then saved as one string
(BOOTCODE$).
The next long section of code (lines 97–1250) reads in the S records from an external disk file (in this
case, BUF34.S19), converts them to integer, and saves them in an array. The techniques used in this
section show how to convert ASCII S records to binary form that can be sent (bootloaded) to an
M68HC11.
This S-record translator only looks for the S1 records that contain the actual object code. All other
S-record types are ignored.
When an S1 record is found (lines 1000–1024), the next two characters form the hex byte giving the
number of hex bytes to follow. This byte is converted to integer by the same subroutine that converted the
bootloaded code from the DATA statements. This BYTECOUNT is adjusted by subtracting 3, which
accounts for the address and checksum bytes and leaves just the number of object-code bytes in the
record.
Starting at line 1100, the 2-byte (4-character) starting address is converted to decimal. This address is
the starting address for the object code bytes to follow. An index into the CODE% array is formed by
subtracting the base address initialized at the start of the program from the starting address for this S
record.
A FOR-NEXT loop starting at line 1130 converts the object code bytes to decimal and saves them in the
CODE% array. When all the object code bytes have been converted from the current S record, the
program loops back to find the next S1 record.
100
NORMAL EVBU
OPERATION
JUMPER
+
20 µ F
+12.25 V
COMMON
PROGRAMMING
POWER
47K
VDD
PROGRAM
EPROM
1K
PC0
P5-9 LED
TO P5-18
(XIRQ/V )
PPE
Driving Boot Mode from a Personal Computer
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 213
A problem arose with the BASIC programming technique used. The draft versions of this program tried
saving the object code bytes directly as binary in a string array. This caused "Out of Memory" or "Out of
String Space" errors on both a 2-Mbyte Macintosh and a 640-Kbyte PC. The solution was to make the
array an integer array and perform the integer-to-binary conversion on each byte as it is sent to the target
part.
The one compromise made to accommodate both Macintosh and PC versions of BASIC is in lines 1500
and 1505. Use line 1500 and comment out line 1505 if the program is to be run on a Macintosh, and,
conversely, use line 1505 and comment out line 1500 if a PC is used.
After the COM port is opened, the code to be bootloaded is modified by adding the $FF to the start of the
string. $FF synchronizes the bootloader in the MC68HC711E9 to 1200 baud. The entire string is simply
sent to the COM port by PRINTing the string. This is possible since the string is actually queued in
BASIC’s COM buffer, and the operating system takes care of sending the bytes out one at a time. The
M68HC11 echoes the data received for verification. No automatic verification is provided, though the data
is printed to the screen for manual verification.
Once the MCU has received this bootloaded code, the bootloader automatically jumps to it. The small
bootloaded program in turn includes a jump to the EPROM programming routine in the boot ROM.
Refer to the previous explanation of the EPROM Programming Utility for the following discussion. The
host system sends the first byte to be programmed through the COM port to the SCI of the MCU. The SCI
port on the MCU buffers one byte while receiving another byte, increasing the throughput of the EPROM
programming operation by sending the second byte while the first is being programmed.
When the first byte has been programmed, the MCU reads the EPROM location and sends the result back
to the host system. The host then compares what was actually programmed to what was originally sent.
A message indicating which byte is being verified is displayed in the lower half of the screen. If there is
an error, it is displayed at the top of the screen.
As soon as the first byte is verified, the third byte is sent. In the meantime, the MCU has already started
programming the second byte. This process of verifying and queueing a byte continues until the host
finishes sending data. If the programming is completely successful, no error messages will have been
displayed at the top of the screen. Subroutines follow the end of the program to handle some of the
repetitive tasks. These routines are short, and the commenting in the source code should be sufficient
explanation.
Modifications
This example programmed version 3.4 of the BUFFALO monitor into the EPROM of an MC68HC711E9;
the changes to the BASIC program to download some other program are minor.
The necessary changes are:
1. In line 30, the length of the program to be downloaded must be assigned to the variable
CODESIZE%.
2. Also in line 30, the starting address of the program is assigned to the variable ADRSTART.
3. In line 9570, the start address of the program is stored in the third and fourth items in that DATA
statement in hexadecimal.
4. If any changes are made to the number of bytes in the boot code in the DATA statements in lines
9500–9580, then the new count must be set in the variable "BOOTCOUNT" in line 25.
M68HC11 Bootstrap Mode, Rev. 1.1
214 Freescale Semiconductor
Driving Boot Mode from a Personal Computer
Operation
Configure the EVBU for boot mode operation by putting a jumper at J3. Ensure that the trace command
jumper at J7 is not installed because this would connect the 12-V programming voltage to the OC5 output
of the MCU.
Connect the EVBU to its dc power supply. When it is time to program the MCU EPROM, turn on the
12-volt programming power supply to the new circuitry in the wire-wrap area.
Connect the EVBU serial port to the appropriate serial port on the host system. For the Macintosh, this is
the modem port with a modem cable. For the MS-DOS® computer, it is connected to COM1 with a straight
through or modem cable. Power up the host system and start the BASIC program. If the program has not
been compiled, this is accomplished from within the appropriate BASIC compiler or interpreter. Power up
the EVBU.
Answer the prompt for filename with either a [RETURN] to accept the default shown or by typing in a new
filename and pressing [RETURN].
The program will inform the user that it is working on converting the file from S records to binary. This
process will take from 30 seconds to a few minutes, depending on the computer.
A prompt reading, "Comm port open?" will appear at the end of the file conversion. This is the last chance
to ensure that everything is properly configured on the EVBU. Pressing [RETURN] will send the bootcode
to the target MC68HC711E9. The program then informs the user that the bootload code is being sent to
the target, and the results of the echoing of this code are displayed on the screen.
Another prompt reading "Programming is ready to begin. Are you?" will appear. Turn on the 12-volt
programming power supply and press [RETURN] to start the actual programming of the target EPROM.
A count of the byte being verified will be updated continually on the screen as the programming
progresses. Any failures will be flagged as they occur.
When programming is complete, a message will be displayed as well as a prompt requesting the user to
press [RETURN] to quit.
Turn off the 12-volt programming power supply before turning off 5 volts to the EVBU.
® MS-DOS is a registered trademark of Microsoft Corporation in the United States and oth175190er countries.
Listing 2. BASIC Program for Personal Computer
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 215
Listing 2. BASIC Program for Personal Computer
1 ' ***********************************************************************
2 ' *
3 ' * E9BUF.BAS - A PROGRAM TO DEMONSTRATE THE USE OF THE BOOT MODE
4 ' * ON THE HC11 BY PROGRAMMING AN HC711E9 WITH
5 ' * BUFFALO 3.4
6 ' *
7 ' * REQUIRES THAT THE S-RECORDS FOR BUFFALO (BUF34.S19)
8 ' * BE AVAILABLE IN THE SAME DIRECTORY OR FOLDER
9 ' *
10 '* THIS PROGRAM HAS BEEN RUN BOTH ON A MS-DOS COMPUTER
11 '* USING QUICKBASIC 4.5 AND ON A MACINTOSH USING
12 '* QUICKBASIC 1.0.
14 '*
15 '************************************************************************
25 H$ = "0123456789ABCDEF" 'STRING TO USE FOR HEX CONVERSIONS
30 DEFINT B, I: CODESIZE% = 8192: ADRSTART= 57344!
35 BOOTCOUNT = 25 'NUMBER OF BYTES IN BOOT CODE
40 DIM CODE%(CODESIZE%) 'BUFFALO 3.4 IS 8K BYTES LONG
45 BOOTCODE$ = "" 'INITIALIZE BOOTCODE$ TO NULL
49 REM ***** READ IN AND SAVE THE CODE TO BE BOOT LOADED *****
50 FOR I = 1 TO BOOTCOUNT '# OF BYTES IN BOOT CODE
55 READ Q$
60 A$ = MID$(Q$, 1, 1)
65 GOSUB 7000 'CONVERTS HEX DIGIT TO DECIMAL
70 TEMP = 16 * X 'HANG ON TO UPPER DIGIT
75 A$ = MID$(Q$, 2, 1)
80 GOSUB 7000
85 TEMP = TEMP + X
90 BOOTCODE$ = BOOTCODE$ + CHR$(TEMP) 'BUILD BOOT CODE
95 NEXT I
96 REM ***** S-RECORD CONVERSION STARTS HERE *****
97 FILNAM$="BUF34.S19" 'DEFAULT FILE NAME FOR S-RECORDS
100 CLS
105 PRINT "Filename.ext of S-record file to be downloaded (";FILNAM$;") ";
107 INPUT Q$
110 IF Q$<>"" THEN FILNAM$=Q$
120 OPEN FILNAM$ FOR INPUT AS #1
130 PRINT : PRINT "Converting "; FILNAM$; " to binary..."
999 REM ***** SCANS FOR 'S1' RECORDS *****
1000 GOSUB 6000 'GET 1 CHARACTER FROM INPUT FILE
1010 IF FLAG THEN 1250 'FLAG IS EOF FLAG FROM SUBROUTINE
1020 IF A$ <> "S" THEN 1000
1022 GOSUB 6000
1024 IF A$ <> "1" THEN 1000
1029 REM ***** S1 RECORD FOUND, NEXT 2 HEX DIGITS ARE THE BYTE COUNT *****
1030 GOSUB 6000
1040 GOSUB 7000 'RETURNS DECIMAL IN X
1050 BYTECOUNT = 16 * X 'ADJUST FOR HIGH NIBBLE
1060 GOSUB 6000
1070 GOSUB 7000
1080 BYTECOUNT = BYTECOUNT + X 'ADD LOW NIBBLE
M68HC11 Bootstrap Mode, Rev. 1.1
216 Freescale Semiconductor
Listing 2. BASIC Program for Personal Computer
1090 BYTECOUNT = BYTECOUNT - 3 'ADJUST FOR ADDRESS + CHECKSUM
1099 REM ***** NEXT 4 HEX DIGITS BECOME THE STARTING ADDRESS FOR THE DATA *****
1100 GOSUB 6000 'GET FIRST NIBBLE OF ADDRESS
1102 GOSUB 7000 'CONVERT TO DECIMAL
1104 ADDRESS= 4096 * X
1106 GOSUB 6000 'GET NEXT NIBBLE
1108 GOSUB 7000
1110 ADDRESS= ADDRESS+ 256 * X
1112 GOSUB 6000
1114 GOSUB 7000
1116 ADDRESS= ADDRESS+ 16 * X
1118 GOSUB 6000
1120 GOSUB 7000
1122 ADDRESS= ADDRESS+ X
1124 ARRAYCNT = ADDRESS-ADRSTART 'INDEX INTO ARRAY
1129 REM ***** CONVERT THE DATA DIGITS TO BINARY AND SAVE IN THE ARRAY *****
1130 FOR I = 1 TO BYTECOUNT
1140 GOSUB 6000
1150 GOSUB 7000
1160 Y = 16 * X 'SAVE UPPER NIBBLE OF BYTE
1170 GOSUB 6000
1180 GOSUB 7000
1190 Y = Y + X 'ADD LOWER NIBBLE
1200 CODE%(ARRAYCNT) = Y 'SAVE BYTE IN ARRAY
1210 ARRAYCNT = ARRAYCNT + 1 'INCREMENT ARRAY INDEX
1220 NEXT I
1230 GOTO 1000
1250 CLOSE 1
1499 REM ***** DUMP BOOTLOAD CODE TO PART *****
1500 'OPEN "R",#2,"COM1:1200,N,8,1" 'Macintosh COM statement
1505 OPEN "COM1:1200,N,8,1,CD0,CS0,DS0,RS" FOR RANDOM AS #2 'DOS COM statement
1510 INPUT "Comm port open"; Q$
1512 WHILE LOC(2) >0 'FLUSH INPUT BUFFER
1513 GOSUB 8020
1514 WEND
1515 PRINT : PRINT "Sending bootload code to target part..."
1520 A$ = CHR$(255) + BOOTCODE$ 'ADD HEX FF TO SET BAUD RATE ON TARGET HC11
1530 GOSUB 6500
1540 PRINT
1550 FOR I = 1 TO BOOTCOUNT '# OF BYTES IN BOOT CODE BEING ECHOED
1560 GOSUB 8000
1564 K=ASC(B$):GOSUB 8500
1565 PRINT "Character #"; I; " received = "; HX$
1570 NEXT I
1590 PRINT "Programming is ready to begin.": INPUT "Are you ready"; Q$
1595 CLS
1597 WHILE LOC(2) > 0 'FLUSH INPUT BUFFER
1598 GOSUB 8020
1599 WEND
1600 XMT = 0: RCV = 0 'POINTERS TO XMIT AND RECEIVE BYTES
1610 A$ = CHR$(CODE%(XMT))
1620 GOSUB 6500 'SEND FIRST BYTE
1625 FOR I = 1 TO CODESIZE% - 1 'ZERO BASED ARRAY 0 -> CODESIZE-1
1630 A$ = CHR$(CODE%(I)) 'SEND SECOND BYTE TO GET ONE IN QUEUE
1635 GOSUB 6500 'SEND IT
Listing 2. BASIC Program for Personal Computer
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 217
1640 GOSUB 8000 'GET BYTE FOR VERIFICATION
1650 RCV = I - 1
1660 LOCATE 10,1:PRINT "Verifying byte #"; I; " "
1664 IF CHR$(CODE%(RCV)) = B$ THEN 1670
1665 K=CODE%(RCV):GOSUB 8500
1666 LOCATE 1,1:PRINT "Byte #"; I; " ", " - Sent "; HX$;
1668 K=ASC(B$):GOSUB 8500
1669 PRINT " Received "; HX$;
1670 NEXT I
1680 GOSUB 8000 'GET BYTE FOR VERIFICATION
1690 RCV = CODESIZE% - 1
1700 LOCATE 10,1:PRINT "Verifying byte #"; CODESIZE%; " "
1710 IF CHR$(CODE%(RCV)) = B$ THEN 1720
1713 K=CODE(RCV):GOSUB 8500
1714 LOCATE 1,1:PRINT "Byte #"; CODESIZE%; " ", " - Sent "; HX$;
1715 K=ASC(B$):GOSUB 8500
1716 PRINT " Received "; HX$;
1720 LOCATE 8, 1: PRINT : PRINT "Done!!!!"
4900 CLOSE
4910 INPUT "Press [RETURN] to quit...", Q$
5000 END
5900 '***********************************************************************
5910 '* SUBROUTINE TO READ IN ONE BYTE FROM A DISK FILE
5930 '* RETURNS BYTE IN A$
5940 '***********************************************************************
6000 FLAG = 0
6010 IF EOF(1) THEN FLAG = 1: RETURN
6020 A$ = INPUT$(1, #1)
6030 RETURN
6490 '***********************************************************************
6492 '* SUBROUTINE TO SEND THE STRING IN A$ OUT TO THE DEVICE
6494 '* OPENED AS FILE #2.
6496 '***********************************************************************
6500 PRINT #2, A$;
6510 RETURN
6590 '***********************************************************************
6594 '* SUBROUTINE THAT CONVERTS THE HEX DIGIT IN A$ TO AN INTEGER
6596 '***********************************************************************
7000 X = INSTR(H$, A$)
7010 IF X = 0 THEN FLAG = 1
7020 X = X - 1
7030 RETURN
7990 '**********************************************************************
7992 '* SUBROUTINE TO READ IN ONE BYTE THROUGH THE COMM PORT OPENED
7994 '* AS FILE #2. WAITS INDEFINITELY FOR THE BYTE TO BE
7996 '* RECEIVED. SUBROUTINE WILL BE ABORTED BY ANY
7998 '* KEYBOARD INPUT. RETURNS BYTE IN B$. USES Q$.
7999 '**********************************************************************
8000 WHILE LOC(2) = 0 'WAIT FOR COMM PORT INPUT
8005 Q$ = INKEY$: IF Q$ <> "" THEN 4900 'IF ANY KEY PRESSED, THEN ABORT
8010 WEND
8020 B$ = INPUT$(1, #2)
8030 RETURN
8490 '************************************************************************
M68HC11 Bootstrap Mode, Rev. 1.1
218 Freescale Semiconductor
Common Bootstrap Mode Problems
8491 '* DECIMAL TO HEX CONVERSION
8492 '* INPUT: K - INTEGER TO BE CONVERTED
8493 '* OUTPUT: HX$ - TWO CHARACTER STRING WITH HEX CONVERSION
8494 '************************************************************************
8500 IF K > 255 THEN HX$="Too big":GOTO 8530
8510 HX$=MID$(H$,K\16+1,1) 'UPPER NIBBLE
8520 HX$=HX$+MID$(H$,(K MOD 16)+1,1) 'LOWER NIBBLE
8530 RETURN
9499 '******************** BOOT CODE ****************************************
9500 DATA 86, 23 'LDAA #$23
9510 DATA B7, 10, 02 'STAA OPT2 make port C wire or
9520 DATA 86, FE 'LDAA #$FE
9530 DATA B7, 10, 03 'STAA PORTC light 1 LED on port C bit 0
9540 DATA C6, FF 'LDAB #$FF
9550 DATA F7, 10, 07 'STAB DDRC make port C outputs
9560 DATA CE, 0F, A0 'LDX #4000 2msec at 2MHz
9570 DATA 18, CE, E0, 00 'LDY #$E000 Start of BUFFALO 3.4
9580 DATA 7E, BF, 00 'JMP $BF00 EPROM routine start address
9590 '***********************************************************************
Common Bootstrap Mode Problems
It is not unusual for a user to encounter problems with bootstrap mode because it is new to many users.
By knowing some of the common difficulties, the user can avoid them or at least recognize and quickly
correct them.
Reset Conditions vs. Conditions as Bootloaded Program Starts
It is common to confuse the reset state of systems and control bits with the state of these systems and
control bits when a bootloaded program in RAM starts.
Between these times, the bootloader program is executed, which changes the states of some systems
and control bits:
• The SCI system is initialized and turned on (Rx and Tx).
• The SCI system has control of the PD0 and PD1 pins.
• Port D outputs are configured for wire-OR operation.
• The stack pointer is initialized to the top of RAM.
• Time has passed (two or more SCI character times).
• Timer has advanced from its reset count value.
Users also forget that bootstrap mode is a special mode. Thus, privileged control bits are accessible, and
write protection for some registers is not in effect. The bootstrap ROM is in the memory map. The DISR
bit in the TEST1 control register is set, which disables resets from the COP and clock monitor systems.
Since bootstrap is a special mode, these conditions can be changed by software. The bus can even be
switched from single-chip mode to expanded mode to gain access to external memories and peripherals.
AN1060 — Rev. 1.0
MOTOROLA M68HC11 Bootstrap Mode 219
Application Note
Common Bootstrap Mode Problems
Table 2. Summary of Boot-ROM-Related Features
MCU Part
BOOT
ROM
Revision
(@$BFD1)
Mask Set
I.D.
(@$BFD2,3)
MCU Type
I.D.
(@$BFD4,5)
Security Download
Length
JMP on
BRK or $00(1)
NOTES:
1. By sending $00 or a break as the first SCI character after reset in bootstrap mode, a jump (JMP) is executed to the address in this table rather than
doing a download. Unless otherwise noted, this address is the start of EEPROM. Tying RxD to TxD and using a pullup resistor from TxD to VDD will
cause the SCI to see a break as the first received character.
JMP
to RAM(2)
2. If $55 is received as the first character after reset in bootstrap mode, a jump (JMP) is executed to the start of on-chip RAM rather than doing a
download. This $55 character must be sent at the default baud rate (7812 baud @ E = 2 MHz). For devices with variable-length download, the same
effect can be achieved by sending $FF and no other SCI characters. After four SCI character times, the download terminates, and a jump (JMP) to
the start of RAM is executed.
The jump to RAM feature is only useful if the RAM was previously loaded with a meaningful program.
Default
RAM
Location
PROGRAM(3)
and UPLOAD(4)
Utility
3. A callable utility subroutine is included in the bootstrap ROM of the indicated versions to program bytes of on-chip EPROM with data received via the
SCI.
4. A callable utility subroutine is included in the bootstrap ROM of the indicated versions to upload contents of on-chip memory to a host computer via
the SCI.
Notes
MC68HC11A0
MC68HC11A1
MC68HC11A8
MC68SEC11A8
—
—
—
—
—
—
—
—
Mask set #
Mask set #
Mask set #
Mask set #
—
—
—
Ye s
256
256
256
256
$B600
$B600
$B600
$B600
$0000
$0000
$0000
$0000
$0000–FF
$0000–FF
$0000–FF
$0000–FF
—
—
—
—
(5)
(5)
(5)
(5)
5. The complete listing for this bootstrap ROM may be found in the M68HC11 Reference Manual, Freescale document order number M68HC11RM/AD.
MC68HC11D3
MC68HC711D3
$00
$42(B)
ROM I.D. #
$0000
$11D3
$71D3
—
—
0–192
0–192
$F000–ROM
$F000–EPROM
—
—
$0040–FF
$0040–FF
—
Ye s
(6)
(6)
6. The complete listing for this bootstrap ROM is available in the freeware area of the Freescale Web site.
MC68HC811E2
MC68SEC811E2
—
—
$0000
—
$E2E2
$E25C
—
Ye s
256
256
$B600
$B600
$0000
$0000
$0000–FF
$0000–FF
—
—
(5)
(5)
MC68HC11E0
MC68HC11E1
MC68HC11E9
MC68SEC11E9
—
—
—
—
ROM I.D. #
ROM I.D. #
ROM I.D. #
ROM I.D. #
$E9E9
$E9E9
$E9E9
$E95C
—
—
—
Ye s
0–512
0–512
0–512
0–512
$B600
$B600
$B600
$B600
—
—
—
—
$0000–1FF
$0000–1FF
$0000–1FF
$0000–1FF
—
—
—
—
(5)
(5)
(5)
(5)
MC68HC711E9 $41(A) $0000 $71E9 — 0–512 $B600 — $0000–1FF Yes
MC68HC11F1 $42(B) $0000 $F1F1 — 0–1024 $FE00 — $0000–3FF — (6), (7)
7. Due to the extra program space needed for EEPROM security on this device, there are no pseudo-vectors for SCI, SPI, PAIF, PAOVF, TOF, OC5F,
or OC4F interrupts.
MC68HC11K4
MC68HC711K4
$30(0)
$42(B)
ROM I.D. #
$0000
$044B
$744B
—
—
0–768
0–768
$0D80
$0D80
—
—
$0080–37F
$0080–37F
—
Ye s
(6), (8)
(6), (8)
8. This bootloader extends the automatic software detection of baud rates to include 9600 baud at 2-MHz E-clock rate.
M68HC11 Bootstrap Mode, Rev. 1.1
220 Freescale Semiconductor
Common Bootstrap Mode Problems
Connecting RxD to VSS Does Not Cause the SCI to Receive a Break
To force an immediate jump to the start of EEPROM, the bootstrap firmware looks for the first received
character to be $00 (or break). The data reception logic in the SCI looks for a 1-to-0 transition on the RxD
pin to synchronize to the beginning of a receive character. If the RxD pin is tied to ground, no 1-to-0
transition occurs. The SCI transmitter sends a break character when the bootloader firmware starts, and
this break character can be fed back to the RxD pin to cause the jump to EEPROM. Since TxD is
configured as an open-drain output, a pullup resistor is required.
$FF Character Is Required before Loading into RAM
The initial character (usually $FF) that sets the download baud rate is often forgotten.
Original M68HC11 Versions Required Exactly 256 Bytes to be Downloaded to RAM
Even users that know about the 256 bytes of download data sometimes forget the initial $FF that makes
the total number of bytes required for the entire download operation equal to 256 + 1 or 257 bytes.
Variable-Length Download
When on-chip RAM surpassed 256 bytes, the time required to serially load this many characters became
more significant. The variable-length download feature allows shorter programs to be loaded without
sacrificing compatibility with earlier fixed-length download versions of the bootloader. The end of a
download is indicated by an idle RxD line for at least four character times. If a personal computer is being
used to send the download data to the MCU, there can be problems keeping characters close enough
together to avoid tripping the end-of-download detect mechanism. Using 1200 as the baud rate rather
than the faster default rate may help this problem.
Assemblers often produce S-record encoded programs which must be converted to binary before
bootloading them to the MCU. The process of reading S-record data from a file and translating it to binary
can be slow, depending on the personal computer and the programming language used for the
translation. One strategy that can be used to overcome this problem is to translate the file into binary and
store it into a RAM array before starting the download process. Data can then be read and downloaded
without the translation or file-read delays.
The end-of-download mechanism goes into effect when the initial $FF is received to set the baud rate.
Any amount of time may pass between reset and when the $FF is sent to start the download process.
EPROM/OTP Versions of M68HC11 Have an EPROM Emulation Mode
The conditions that configure the MCU for EPROM emulation mode are essentially the same as those for
resetting the MCU in bootstrap mode. While RESET is low and mode select pins are configured for
bootstrap mode (low), the MCU is configured for EPROM emulation mode.
The port pins that are used for EPROM data I/O lines may be inputs or outputs, depending on the pin that
is emulating the EPROM output enable pin (OE). To make these data pins appear as high-impedance
inputs as they would on a non-EPROM part in reset, connect the PB7/(OE) pin to a pullup resistor.
Boot ROM Variations
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 221
Bootloading a Program to Performa ROM Checksum
The bootloader ROM must be turned off before performing the checksum program. To remove the boot
ROM from the memory map, clear the RBOOT bit in the HPRIO register. This is normally a write-protected
bit that is 0, but in bootstrap mode it is reset to 1 and can be written. If the boot ROM is not disabled, the
checksum routine will read the contents of the boot ROM rather than the user’s mask ROM or EPROM at
the same addresses.
Inherent Delays Caused by Double Buffering of SCI Data
This problem is troublesome in cases where one MCU is bootloading to another MCU.
Because of transmitter double buffering, there may be one character in the serial shifter as a new
character is written into the transmit data register. In cases such as downloading in which this 2-character
pipeline is kept full, a 2-character time delay occurs between when a character is written to the transmit
data register and when that character finishes transmitting. A little more than one more character time
delay occurs between the target MCU receiving the character and echoing it back. If the master MCU
waits for the echo of each downloaded character before sending the next one, the download process
takes about twice as long as it would if transmission is treated as a separate process or if verify data is
ignored.
Boot ROM Variations
Different versions of the M68HC11 have different versions of the bootstrap ROM program. Table 3
summarizes the features of the boot ROMs in 16 members of the M68HC11 Family.
The boot ROMs for the MC68HC11F1, the MC68HC711K4, and the MC68HC11K4 allow additional
choices of baud rates for bootloader communications. For the three new baud rates, the first character
used to determine the baud rate is not $FF as it was in earlier M68HC11s. The intercharacter delay that
terminates the variable-length download is also different for these new baud rates. Table 3 shows the
synchronization characters, delay times, and baud rates as they relate to E-clock frequency.
Commented Boot ROM Listing
Listing 3. MC68HC711E9 Bootloader ROM contains a complete commented listing of the boot ROM
program in the MC68HC711E9 version of the M68HC11. Other versions can be found in Appendix B of
the M68HC11 Reference Manual.
Table 3. Bootloader Baud Rates
Sync
Character
Timeout
Delay
Baud Rates at E Clock =
2 MHz 2.1 MHz 3 MHz 3.15 MHz 4 MHz 4.2 MHz
$FF 4 characters 7812 8192 11,718 12,288 15,624 16,838
$FF 4 characters 1200 1260 1800 1890 2400 2520
$F0 4.9 characters 9600 10,080 14,400 15,120 19,200 20,160
$FD 17.3 characters 5208 5461 7812 8192 10,416 10,922
$FD 13 characters 3906 4096 5859 6144 7812 8192
M68HC11 Bootstrap Mode, Rev. 1.1
222 Freescale Semiconductor
Listing 3. MC68HC711E9 Bootloader ROM
Listing 3. MC68HC711E9 Bootloader ROM
1 ****************************************************
2 * BOOTLOADER FIRMWARE FOR 68HC711E9 - 21 Aug 89
3 ****************************************************
4 * Features of this bootloader are...
5 *
6 * Auto baud select between 7812.5 and 1200 (8 MHz)
7 * 0 - 512 byte variable length download
8 * Jump to EEPROM at $B600 if 1st download byte = $00
9 * PROGRAM - Utility subroutine to program EPROM
10 * UPLOAD - Utility subroutine to dump memory to host
11 * Mask I.D. at $BFD4 = $71E9
12 ****************************************************
13 * Revision A -
14 *
15 * Fixed bug in PROGRAM routine where the first byte
16 * programmed into the EPROM was not transmitted for
17 * verify.
18 * Also added to PROGRAM routine a skip of bytes
19 * which were already programmed to the value desired.
20 *
21 * This new version allows variable length download
22 * by quitting reception of characters when an idle
23 * of at least four character times occurs
24 *
25 ****************************************************
26
27 * EQUATES FOR USE WITH INDEX OFFSET = $1000
28 *
29 0008 PORTD EQU $08
30 000E TCNT EQU $0E
31 0016 TOC1 EQU $16
32 0023 TFLG1 EQU $23
33 * BIT EQUATES FOR TFLG1
34 0080 OC1F EQU $80
35 *
36 0028 SPCR EQU $28 (FOR DWOM BIT)
37 002B BAUD EQU $2B
38 002D SCCR2 EQU $2D
39 002E SCSR EQU $2E
40 002F SCDAT EQU $2F
41 003B PPROG EQU $3B
42 * BIT EQUATES FOR PPROG
43 0020 ELAT EQU $20
44 0001 EPGM EQU $01
45 *
46
47 * MEMORY CONFIGURATION EQUATES
48 *
49 B600 EEPMSTR EQU $B600 Start of EEPROM
50 B7FF EEPMEND EQU $B7FF End of EEPROM
51 *
Listing 3. MC68HC711E9 Bootloader ROM
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 223
52 D000 EPRMSTR EQU $D000 Start of EPROM
53 FFFF EPRMEND EQU $FFFF End of EPROM
54 *
55 0000 RAMSTR EQU $0000
56 01FF RAMEND EQU $01FF
57
58 * DELAY CONSTANTS
59 *
60 0DB0 DELAYS EQU 3504 Delay at slow baud
61 021B DELAYF EQU 539 Delay at fast baud
62 *
63 1068 PROGDEL EQU 4200 2 ms programming delay
64 * At 2.1 MHz
65
66 ****************************************************
67 BF00 ORG $BF00
68 ****************************************************
69
70 * Next two instructions provide a predictable place
71 * to call PROGRAM and UPLOAD even if the routines
72 * change size in future versions.
73 *
74 BF00 7EBF13 PROGRAM JMP PRGROUT EPROM programming utility
75 BF03 UPLOAD EQU * Upload utility
76
77 ****************************************************
78 * UPLOAD - Utility subroutine to send data from
79 * inside the MCU to the host via the SCI interface.
80 * Prior to calling UPLOAD set baud rate, turn on SCI
81 * and set Y=first address to upload.
82 * Bootloader leaves baud set, SCI enabled, and
83 * Y pointing at EPROM start ($D000) so these default
84 * values do not have to be changed typically.
85 * Consecutive locations are sent via SCI in an
86 * infinite loop. Reset stops the upload process.
87 ****************************************************
88 BF03 CE1000 LDX #$1000 Point to internal registers
89 BF06 18A600 UPLOOP LDAA 0,Y Read byte
90 BF09 1F2E80FC BRCLR SCSR,X $80 * Wait for TDRE
91 BF0D A72F STAA SCDAT,X Send it
92 BF0F 1808 INY
93 BF11 20F3 BRA UPLOOP Next...
94
95 ****************************************************
96 * PROGRAM - Utility subroutine to program EPROM.
97 * Prior to calling PROGRAM set baud rate, turn on SCI
98 * set X=2ms prog delay constant, and set Y=first
99 * address to program. SP must point to RAM.
100 * Bootloader leaves baud set, SCI enabled, X=4200
101 * and Y pointing at EPROM start ($D000) so these
102 * default values don't have to be changed typically.
103 * Delay constant in X should be equivalent to 2 ms
104 * at 2.1 MHz X=4200; at 1 MHz X=2000.
105 * An external voltage source is required for EPROM
106 * programming.
M68HC11 Bootstrap Mode, Rev. 1.1
224 Freescale Semiconductor
Listing 3. MC68HC711E9 Bootloader ROM
107 * This routine uses 2 bytes of stack space
108 * Routine does not return. Reset to exit.
109 ****************************************************
110 BF13 PRGROUT EQU *
111 BF13 3C PSHX Save program delay constant
112 BF14 CE1000 LDX #$1000 Point to internal registers
113 BF17
114 * Send $FF to indicate ready for program data
115
116 BF17 1F2E80FC BRCLR SCSR,X $80 * Wait for TDRE
117 BF1B 86FF LDAA #$FF
118 BF1D A72F STAA SCDAT,X
119
120 BF1F WAIT1 EQU *
121 BF1F 1F2E20FC BRCLR SCSR,X $20 * Wait for RDRF
122 BF23 E62F LDAB SCDAT,X Get received byte
123 BF25 18E100 CMPB $0,Y See if already programmed
124 BF28 271D BEQ DONEIT If so, skip prog cycle
125 BF2A 8620 LDAA #ELAT Put EPROM in prog mode
126 BF2C A73B STAA PPROG,X
127 BF2E 18E700 STAB 0,Y Write the data
128 BF31 8621 LDAA #ELAT+EPGM
129 BF33 A73B STAA PPROG,X Turn on prog voltage
130 BF35 32 PULA Pull delay constant
131 BF36 33 PULB into D-reg
132 BF37 37 PSHB But also keep delay
133 BF38 36 PSHA keep delay on stack
134 BF39 E30E ADDD TCNT,X Delay const + present TCNT
135 BF3B ED16 STD TOC1,X Schedule OC1 (2ms delay)
136 BF3D 8680 LDAA #OC1F
137 BF3F A723 STAA TFLG1,X Clear any previous flag
138
139 BF41 1F2380FC BRCLR TFLG1,X OC1F * Wait for delay to expire
140 BF45 6F3B CLR PPROG,X Turn off prog voltage
141 *
142 BF47 DONEIT EQU *
143 BF47 1F2E80FC BRCLR SCSR,X $80 * Wait for TDRE
144 BF4B 18A600 LDAA $0,Y Read from EPROM and...
145 BF4E A72F STAA SCDAT,X Xmit for verify
146 BF50 1808 INY Point at next location
147 BF52 20CB BRA WAIT1 Back to top for next
148 * Loops indefinitely as long as more data sent.
149
150 ****************************************************
151 * Main bootloader starts here
152 ****************************************************
153 * RESET vector points to here
154
155 BF54 BEGIN EQU *
156 BF54 8E01FF LDS #RAMEND Initialize stack pntr
157 BF57 CE1000 LDX #$1000 Point at internal regs
158 BF5A 1C2820 BSET SPCR,X $20 Select port D wire-OR mode
159 BF5D CCA20C LDD #$A20C BAUD in A, SCCR2 in B
160 BF60 A72B STAA BAUD,X SCPx = ÷4, SCRx = ÷4
161 * Writing 1 to MSB of BAUD resets count chain
Listing 3. MC68HC711E9 Bootloader ROM
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 225
162 BF62 E72D STAB SCCR2,X Rx and Tx Enabled
163 BF64 CC021B LDD #DELAYF Delay for fast baud rate
164 BF67 ED16 STD TOC1,X Set as default delay
165
166 * Send BREAK to signal ready for download
167 BF69 1C2D01 BSET SCCR2,X $01 Set send break bit
168 BF6C 1E0801FC BRSET PORTD,X $01 * Wait for RxD pin to go low
169 BF70 1D2D01 BCLR SCCR2,X $01 Clear send break bit
170 BF73
171 BF73 1F2E20FC BRCLR SCSR,X $20 * Wait for RDRF
172 BF77 A62F LDAA SCDAT,X Read data
173 * Data will be $00 if BREAK OR $00 received
174 BF79 2603 BNE NOTZERO Bypass JMP if not 0
175 BF7B 7EB600 JMP EEPMSTR Jump to EEPROM if it was 0
176 BF7E NOTZERO EQU *
177 BF7E 81FF CMPA #$FF $FF will be seen as $FF
178 BF80 2708 BEQ BAUDOK If baud was correct
179 * Or else change to ÷104 (÷13 & ÷8) 1200 @ 2MHZ
180 BF82 1C2B33 BSET BAUD,X $33 Works because $22 -> $33
181 BF85 CC0DB0 LDD #DELAYS And switch to slower...
182 BF88 ED16 STD TOC1,X delay constant
183 BF8A BAUDOK EQU *
184 BF8A 18CE0000 LDY #RAMSTR Point at start of RAM
185
186 BF8E WAIT EQU *
187 BF8E EC16 LDD TOC1,X Move delay constant to D
188 BF90 WTLOOP EQU *
189 BF90 1E2E2007 BRSET SCSR,X $20 NEWONE Exit loop if RDRF set
190 BF94 8F XGDX Swap delay count to X
191 BF95 09 DEX Decrement count
192 BF96 8F XGDX Swap back to D
193 BF97 26F7 BNE WTLOOP Loop if not timed out
194 BF99 200F BRA STAR Quit download on timeout
195
196 BF9B NEWONE EQU *
197 BF9B A62F LDAA SCDAT,X Get received data
198 BF9D 18A700 STAA $00,Y Store to next RAM location
199 BFA0 A72F STAA SCDAT,X Transmit it for handshake
200 BFA2 1808 INY Point at next RAM location
201 BFA4 188C0200 CPY #RAMEND+1 See if past end
202 BFA8 26E4 BNE WAIT If not, Get another
203
204 BFAA STAR EQU *
205 BFAA CE1068 LDX #PROGDEL Init X with programming delay
206 BFAD 18CED000 LDY #EPRMSTR Init Y with EPROM start addr
207 BFB1 7E0000 JMP RAMSTR ** EXIT to start of RAM **
208 BFB4
209 ****************************************************
210 * Block fill unused bytes with zeros
211
212 BFB4 000000000000 BSZ $BFD1-*
000000000000
000000000000
000000000000
0000000000
M68HC11 Bootstrap Mode, Rev. 1.1
226 Freescale Semiconductor
Listing 3. MC68HC711E9 Bootloader ROM
213
214 ****************************************************
215 * Boot ROM revision level in ASCII
216 * (ORG $BFD1)
217 BFD1 41 FCC "A"
218 ****************************************************
219 * Mask set I.D. ($0000 FOR EPROM PARTS)
220 * (ORG $BFD2)
221 BFD2 0000 FDB $0000
222 ****************************************************
223 * '711E9 I.D. - Can be used to determine MCU type
224 * (ORG $BFD4)
225 BFD4 71E9 FDB $71E9
226
227 ****************************************************
228 * VECTORS - point to RAM for pseudo-vector JUMPs
229
230 BFD6 00C4 FDB $100-60 SCI
231 BFD8 00C7 FDB $100-57 SPI
232 BFDA 00CA FDB $100-54 PULSE ACCUM INPUT EDGE
233 BFDC 00CD FDB $100-51 PULSE ACCUM OVERFLOW
234 BFDE 00D0 FDB $100-48 TIMER OVERFLOW
235 BFE0 00D3 FDB $100-45 TIMER OUTPUT COMPARE 5
236 BFE2 00D6 FDB $100-42 TIMER OUTPUT COMPARE 4
237 BFE4 00D9 FDB $100-39 TIMER OUTPUT COMPARE 3
238 BFE6 00DC FDB $100-36 TIMER OUTPUT COMPARE 2
239 BFE8 00DF FDB $100-33 TIMER OUTPUT COMPARE 1
240 BFEA 00E2 FDB $100-30 TIMER INPUT CAPTURE 3
241 BFEC 00E5 FDB $100-27 TIMER INPUT CAPTURE 2
242 BFEE 00E8 FDB $100-24 TIMER INPUT CAPTURE 1
243 BFF0 00EB FDB $100-21 REAL TIME INT
244 BFF2 00EE FDB $100-18 IRQ
245 BFF4 00F1 FDB $100-15 XIRQ
246 BFF6 00F4 FDB $100-12 SWI
247 BFF8 00F7 FDB $100-9 ILLEGAL OP-CODE
248 BFFA 00FA FDB $100-6 COP FAIL
249 BFFC 00FD FDB $100-3 CLOCK MONITOR
250 BFFE BF54 FDB BEGIN RESET
251 C000 END
Symbol Table:
Symbol Name Value Def.# Line Number Cross Reference
BAUD 002B *00037 00160 00180
BAUDOK BF8A *00183 00178
BEGIN BF54 *00155 00250
DELAYF 021B *00061 00163
DELAYS 0DB0 *00060 00181
DONEIT BF47 *00142 00124
EEPMEND B7FF *00050
EEPMSTR B600 *00049 00175
ELAT 0020 *00043 00125 00128
EPGM 0001 *00044 00128
EPRMEND FFFF *00053
EPRMSTR D000 *00052 00206
Listing 3. MC68HC711E9 Bootloader ROM
M68HC11 Bootstrap Mode, Rev. 1.1
Freescale Semiconductor 227
NEWONE BF9B *00196 00189
NOTZERO BF7E *00176 00174
OC1F 0080 *00034 00136 00139
PORTD 0008 *00029 00168
PPROG 003B *00041 00126 00129 00140
PRGROUT BF13 *00110 00074
PROGDEL 1068 *00063 00205
PROGRAM BF00 *00074
RAMEND 01FF *00056 00156 00201
RAMSTR 0000 *00055 00184 00207
SCCR2 002D *00038 00162 00167 00169
SCDAT 002F *00040 00091 00118 00122 00145 00172 00197 00199
SCSR 002E *00039 00090 00116 00121 00143 00171 00189
SPCR 0028 *00036 00158
STAR BFAA *00204 00194
TCNT 000E *00030 00134
TFLG1 0023 *00032 00137 00139
TOC1 0016 *00031 00135 00164 00182 00187
UPLOAD BF03 *00075
UPLOOP BF06 *00089 00093
WAIT BF8E *00186 00202
WAIT1 BF1F *00120 00147
WTLOOP BF90 *00188 00193
Errors: None
Labels: 35
Last Program Address: $BFFF
Last Storage Address: $0000
Program Bytes: $0100 256
Storage Bytes: $0000 0
M68HC11 Bootstrap Mode, Rev. 1.1
228 Freescale Semiconductor
Listing 3. MC68HC711E9 Bootloader ROM
© Freescale Semiconductor, Inc., 2005. All rights reserved.
Freescale Semiconductor
Engineering Bulletin
EB184
Rev. 0.1, 07/2005
Enabling the Security Feature
on the MC68HC711E9 Devices
with PCbug11 on the
M68HC711E9PGMR
By Edgar Saenz
Austin, Texas
Introduction
The PCbug11 software, needed along with the M68HC711E9PGMR to program MC68HC711E9 devices,
is available from the download section of the Microcontroller Worldwide Web site:
http://www.freescale.com
Retrieve the file pcbug342.exe (a self-extracting archive) from the MCU11 directory.
Some Freescale evaluation board products also are shipped with PCbug11.
NOTE
For specific information about any of the PCbug11 commands, see the
appropriate sections in the PCbug11 User's Manual (part number
M68PCBUG11/D2), which is available from the Freescale Literature
Distribution Center, as well as the Worldwide Web at
http://www.freescale.com. The file is also on the software download system
and is called pcbug11.pdf.
Enabling the Security Feature on the MC68HC711E9 Devices with PCbug11 on the M68HC711E9PGMR, Rev. 0.1
230 Freescale Semiconductor
To Execute the Program
To Execute the Program
Use this step-by-step procedure to program the MC68HC711E9 device.
Step 1
• Before applying power to the programming board, connect the M68HC711E9PGMR serial port P2
to one of your PC COM ports with a standard 25-pin RS-232 cable. Do not use a null modem cable
or adapter which swaps the transmit and receive signals between the connectors at each end of
the cable.
• Place the MC68HC711E9 part in the PLCC socket on your board.
• Insert the part upside down with the notched corner pointing toward the red power LED.
• Make sure both S1 and S2 switches are turned off.
• Apply +5 volts to +5-V, +12 volts (at most +12.5 volts) to VPP, and ground to GND on your
programmer board’s power connector, P1. The remaining TXD/PD1 and RXD/PD0 connections
are not used in this procedure. They are for gang programming MC68HC711E9 devices, which is
discussed in the M68HC711E9PGMR Manual. You cannot gang program with PCbug11.
• Ensure that the "remove for multi-programming" jumper, J1, below the +5-V power switch has a
fabricated jumper installed.
Step 2
Apply power to the programmer board by moving the +5-V switch to the ON position. From a DOS
command line prompt, start PCbug11this way:
C:\PCBUG11\ > PCBUG11 –E PORT = 1 with the E9PGMR connected to COM1
or
C:\PCBUG11\ > PCBUG11 –E PORT = 2 with the E9PGMR connected to COM2
PCbug11 only supports COM ports 1 and 2. If the proper connections are made and you have a
high-quality cable, you should quickly get a PCbug11 command prompt. If you do receive a Comms fault
error, check the cable and board connections. Most PCbug11 communications problems can be traced
to poorly made cables or bad board connections.
Step 3
PCbug11 defaults to base 10 for its input parameters.
Change this to hexadecimal by typing: CONTROL BASE HEX.
Step 4
Clear the block protect register (BPROT) to allow programming of the MC68HC711E9 EEPROM.
At the PCbug11 command prompt, type: MS 1035 00.
To Execute the Program
Enabling the Security Feature on the MC68HC711E9 Devices with PCbug11 on the M68HC711E9PGMR, Rev. 0.1
Freescale Semiconductor 231
Step 5
The CONFIG register defaults to hexadecimal 103F on the MC68HC711E9. PCBUG11 needs adressing
parameters to allow programming of a specific block of memory so the following parameter must be given.
At the PCbug11 command prompt, type: EEPROM 0.
Then type: EEPROM 103F 103F.
Step 6
Erase the CONFIG to allow byte programming.
At the PCbug11 command prompt, type: EEPROM ERASE BULK 103F.
Step 7
You are now ready to download the program into the EEPROM and EPROM.
At the PCbug11command prompt, type: LOADSC:\MYPROG\MYPROG.S19.
For more details on programming the EPROM, read the engineering bulletin Programming
MC68HC711E9 Devices with PCbug11 and the M68HC11EVB, Freescale document number EB187.
Step 8
You are now ready to enable the security feature on the MCHC711E9.
At the PCbug11 command prompt type: MS 103F 05.
Step 9
After the programming operation is complete, verifyng the CONFIG on the MCHC711E9 is not possible
because in bootstrap mode the default value is always forced.
Step 10
The part is now in secure mode and whatever code you loaded into EEPROM will be erased if you tried
to bring the microcontroller up in either expanded mode or bootstrap mode.
NOTE
It is important to note that the microcontroller will work properly in secure
mode only in single chip mode.
NOTE
If the part is placed in bootstrap or expanded, the code in EEPROM and
RAM will be erased and the microcontroller cannot be reused. The security
software will constantly read the NOSEC bit and lock the part.
Enabling the Security Feature on the MC68HC711E9 Devices with PCbug11 on the M68HC711E9PGMR, Rev. 0.1
232 Freescale Semiconductor
To Execute the Program
© Freescale Semiconductor, Inc., 2005. All rights reserved.
Freescale Semiconductor
Engineering Bulletin
EB188
Rev. 0.1, 07/2005
Enabling the Security Feature
on M68HC811E2 Devices
with PCbug11 on the
M68HC711E9PGMR
By Edgar Saenz
Austin, Texas
Introduction
The PCbug11 software, needed along with the M68HC711E9PGMR to program MC68HC811E2 devices,
is available from the download section of the Microcontroller Worldwide Web site
http://www.freescale.com
Retrieve the file pcbug342.exe (a self-extracting archive) from the MCU11 directory.
Some Freescale evaluation board products also are shipped with PCbug11.
NOTE
For specific information about any of the PCbug11 commands, see the
appropriate sections in the PCbug11 User's Manual (part number
M68PCBUG11/D2), which is available from the Freescale Literature
http://www.freescale.com. The file is also on the software download system
and is called pcbug11.pdf.
Enabling the Security Feature on M68HC811E2 Devices with PCbug11 on the M68HC711E9PGMR, Rev. 0.1
234 Freescale Semiconductor
To Execute the Program
To Execute the Program
Once you have obtained PCbug11, use this step-by-step procedure.
Step 1
• Before applying power to the programming board, connect the M68HC711E9PGMR serial port P2
to one of your PC COM ports with a standard 25 pin RS-232 cable. Do not use a null modem cable
or adapter which swaps the transmit and receive signals between the connectors at each end of
the cable.
• Place your MC68HC811E2 part in the PLCC socket on your board.
• Insert the part upside down with the notched corner pointing toward the red power LED.
• Make sure both S1 and S2 switches are turned off.
• Apply +5 volts to +5 volts and ground to GND on the programmer board’s power connector, P1.
Applying voltage to the VPP pin is not necessary.
Step 2
Apply power to the programmer board by moving the +5-volt switch to the ON position.
From a DOS command line prompt, start PCbug11 this way:
• C:\PCBUG11\> PCBUG11 –A PORT = 1 when the E9PGMR connected to COM1 or
• C:\PCBUG11\> PCBUG11 –A PORT = 2 when the E9PGMR connected to COM2
PCbug11only supports COM ports 1 and 2.
Step 3
PCbug11 defaults to base ten for its input parameters.
Change this to hexadecimal by typing: CONTROL BASE HEX
Step 4
Clear the block protect register (BPROT) to allow programming of the MC68HC811E2 EEPROM.
At the PCbug11 command prompt, type: MS 1035 00
Step 5
PCbug11 defaults to a 512-byte EEPROM array located at $B600. This must be changed since the
EEPROM is, by default, located at $F800 on the MC68HC811E2.
At the PCbug11 command prompt, type: EEPROM 0
Then type: EEPROM F800 FFFF
Then type: EEPROM 103F 103F
This assumes you have not relocated the EEPROM by previously reprogramming the upper 4 bits of the
CONFIG register. But if you have done this and your S records reside in an address range other than
$F800 to $FFFF, you will need to first relocate the EEPROM.
To Execute the Program
Enabling the Security Feature on M68HC811E2 Devices with PCbug11 on the M68HC711E9PGMR, Rev. 0.1
Freescale Semiconductor 235
Step 6
Erase the CONFIG to allow programming of NOSEC bit (bit 3). It is also recommended to program the
EEPROM at this point before programming the CONFIG register. Refer to the engineering bulletin
Programming MC68HC811E2 Devices with PCbug11 and the M68HC711E9PGMR, Freescale document
number EB184.
At the PCbug11command prompt, type: EEPROM ERASE BULK 103F
Step 7
You are now ready to enable the security feature on the MCHC811E2.
At the PCbug11 command prompt, type: MS 103F 05
The value $05 assumes the EEPROM is to be mapped from $0800 to $0FFF.
Step 8
After the programming operation is complete, verifying the CONFIG on the MCHC811E2 is not possible
because in bootstrap mode the default value is always forced.
Step 9
The part is now in secure mode and whatever code you loaded into EEPROM will be erased if you tried
to bring the microcontroller up in either expanded mode or bootstrap mode. The microcontroller will work
properly in the secure mode only in single chip mode.
NOTE
If the part is placed in bootstrap mode or expanded mode, the code in
EEPROM and RAM will be erased the microcontroller can be reused.
Enabling the Security Feature on M68HC811E2 Devices with PCbug11 on the M68HC711E9PGMR, Rev. 0.1
236 Freescale Semiconductor
To Execute the Program
© Freescale Semiconductor, Inc., 2005. All rights reserved.
Freescale Semiconductor
Engineering Bulletin
EB296
Rev. 0.1, 07/2005
Programming MC68HC711E9
Devices with PCbug11
and the M68HC11EVBU
By John Bodnar
Austin, Texas
Introduction
The PCbug1software, needed along with the M68HC11EVBU to program MC68HC711E9 devices, is
available from the download section of the Microcontroller Worldwide Web site
http://www.freescale.com
Retrieve the file pcbug342.exe (a self-extracting archive) from the MCU11 directory.
Some Freescale evaluation board products also are shipped with PCbug11.
NOTE
For specific information about any of the PCbug11 commands, see the
appropriate sections in the PCbug11 User's Manual (part number
M68PCBUG11/D2), which is available from the Freescale Literature
Distribution Center, as well as the Worldwide Web at
http://www.freescale.com. The file is also on the software download system
and is called pcbug11.pdf.
Programming MC68HC711E9 Devices with PCbug11 and the M68HC11EVBU, Rev. 0.1
238 Freescale Semiconductor
Programming Procedure
Programming Procedure
Once you have obtained PCbug11, use this step-by-step procedure to program your MC68HC711E9 part.
Step 1
• Before applying power to the EVBU, remove the jumper from J7 and place it across J3 to ground
the MODB pin.
• Place a jumper across J4 to ground the MODA pin. This will force the EVBU into special bootstrap
mode on power up.
• Remove the resident MC68HC11E9 MCU from the EVBU.
• Place your MC68HC711E9 in the open socket with the notched corner of the part aligned with the
notch on the PLCC socket.
• Connect the EVBU to one of your PC COM ports. Apply +5 volts to VDD and ground to GND on the
power connector of your EVBU.
Also take note of P4 connector pin 18. In step 5, you will connect a +12-volt (at most +12.5 volts)
programming voltage through a 100-Ω current limiting resistor to the XIRQ pin. Do not connect this
programming voltage until you are instructed to do so in step 5.
Step 2
• From a DOS command line prompt, start PCbug11 with
– C:\PCBUG11\> PCBUG11 –E PORT = 1 with the EVBU connected to COM1
– C:\PCBUG11\> PCBUG11 –E PORT = 2 with the EVBU connected to COM2
PCbug11 only supports COM ports 1 and 2. If you have made the proper connections and have a high
quality cable, you should quickly get a PCbug11 command prompt. If you do receive a Comms fault error,
check your cable and board connections. Most PCbug11 communications problems can be traced to
poorly made cables or bad board connections.
Step 3
• PCbug11 defaults to base 10 for its input parameters; change this to hexadecimal by typing
CONTROL BASE HEX
Step 4
• You must declare the addresses of the EPROM array to PCbug11. To do this, type:
EPROM D000 FFFF
Step 5
You are now ready to download your program into the EPROM.
• Connect +12 volts (at most +12.5 volts) through a 100-Ω current limiting resistor to P4 connector
pin 18, the XIRQ* pin.
• At the PCbug11 command prompt type: LOADS C:\MYPROG\ISHERE.S19
Substitute the name of your program into the command above. Use a full path name if your program is
not located in the same directory as PCbug11.
Programming Procedure
Programming MC68HC711E9 Devices with PCbug11 and the M68HC11EVBU, Rev. 0.1
Freescale Semiconductor 239
Step 6
After the programming operation is complete, PCbug11 will display this message
Total bytes loaded: $xxxx
Total bytes programmed: $yyyy
• You should now remove the programming voltage from P4 connector pin 18, the XIRQ* pin.
• Each ORG directive in your assembly language source will cause a pair of these lines to be
generated. For this operation, $yyyy will be incremented by the size of each block of code
programmed into the EPROM of the MC68HC711E9.
• PCbug11 will display the above message whether or not the programming operation was
successful. As a precaution, you should have PCbug11 verify your code.
• At the PCbug11 command prompt type: VERF C:\MYPROG\ISHERE.S19
Substitute the name of your program into the command above. Use a full path name if your program is
not located in the same directory as PCbug11.
If the verify operation fails, a list of addresses which did not program correctly is displayed. Should this
occur, you probably need to erase your part more completely. To do so, allow the MC68HC711E9 to sit
for at least 45 minutes under an ultraviolet light source. Attempt the programming operation again. If you
have purchased devices in plastic packages (one-time programmable parts), you will need to try again
with a new, unprogrammed device.
Programming MC68HC711E9 Devices with PCbug11 and the M68HC11EVBU, Rev. 0.1
240 Freescale Semiconductor
Programming Procedure
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© Freescale Semiconductor, Inc. 2005. All rights reserved.
M68HC11E
Rev. 5.1, 07/2005
