AN1237 - Motorola / Freescale Semiconductor

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AN1237/D

SEMICONDUCTOR

MOTOROLA

APPLICATION NOTE

Using M68HC11 Microcontrollers with

WSI Programmable Peripheral Devices

by Steve Torp - Motorola Semiconductor

Karen Spesard - WSI

INTRODUCTION

Following system development using M68HC711 microcontroller (MCU) devices with EPROM or one time

programmable ROM (OTPROM), a final design is often implemented using an equivalent mask-pro-

grammed M68HC11 device. However, there is a quick, cost-effective alternative to this method of going to

production.

WSI manufactures a complete line of PSD programmable MCU peripherals that make it possible to use a

ROM-less M68HC11 derivative instead of a mask-programmed device. PSD devices combine EPROM,

SRAM, programmable logic for memory map decoding, programmable I/O ports, an address latch, power

management, and other capabilities on a single chip. A “twin chip” solution can increase flexibility, provide

expanded memory and enhanced I/O, lower power consumption, and lower cost — all with a minimum of

software and hardware modifications.

This application note describes the process of converting from a prototype design that uses an M68HC711

device to a production design that uses a low-cost M68HC11 derivative and a WSI PSD.

CONVERSION PROCEDURES

There are eight steps in the conversion process. Each is discussed in detail in the following text.

1. Choose the M68HC11 and PSD

2. Add the PSD to the design

3. Configure the M68HC11 for expanded mode operation

4. Configure the PSD

5. Make memory map and I/O port selections

6. Modify M68HC11 code to address memory and I/O

7. Integrate M68HC11 code with PSD configuration data

8. Program the PSD

CHOOSE THE M68HC11 AND PSD

The M68HC11 family offers a wide range of operating voltage and frequency selections.

Table 1

shows

M68HC11 Family devices, including M68L11 low-power devices, that can be used in two-chip systems.

EPROM/OTPROM devices are shown in bold. WSI PSDs are available in a variety of configurations. PSDs

provide a larger memory size, I/O port expansion, and programmable logic to an M68HC11 system. Low-

power PSDs are a perfect complement to M68L11 MCUs.

MOTOROLA AN1237/D

Table 1 Motorola M68HC11 Devices

Motorola Part Number ROM RAM EEPROM I/O A/D

MC68HC11A0

MC68L11A0

MC68HC11A1

MC68L11A1

MC68HC11A7

MC68L11A7

MC68HC11A8

MC68L11A8

256

512

Yes

MC68HC11C0 0 256 0 35 Yes

MC68HC711D3 4K 192 0 32 No

MC68HC11D0

MC68HC11D3 0

4K 192

192 0

014

32 No

MC68HC711E9 12K 512 512 38 Yes

MC68HC11E0

MC68L11E0

MC68HC11E1

MC68L11E1

MC68HC11E8

MC68L11E8

MC68HC11E9

MC68L11E9

12K

512

Yes

MC68HC711E20 20K 768 512 38 Yes

MC68HC11E20 20K 768 512 38 Yes

MC68HC811E2 0 256 2K 38 Yes

MC68HC11F1

MC68L11F1 0 1K 512 30 Yes

MC68HC711K4 24K 768 640 62 Yes

MC68HC11K0

MC68L11K0

MC68HC11K1

MC68L11K1

MC68HC11K3

MC68L11K3

MC68HC11K4

MC68L11K4

24K

768

640

Yes

MC68HC711L6 16K 512 512 46 Yes

MC68HC11L0

MC68L11L0

MC68HC11L1

MC68L11L1

MC68HC11L5

MC68L11L5

MC68HC11L6

MC68L11L6

16K

512

Yes

MC68HC711P2 32K 1K 640 62 Yes

MC68HC11P2 32K 1K 640 62 Yes

AN1237/D MOTOROLA

Table 2

shows PSD devices that are recommended for use with M68HC11 and M68L11 family members.

Table 3

shows typical twin-chip alternatives to particular M68HC711 or M68L711 systems.

ADD THE PSD TO THE DESIGN

Migration from an M68HC711 single-chip system to an M68HC11/PSD system can be accomplished in one

of three ways.

1. By building a daughter board that plugs into the MCU socket on an existing printed circuit board. The

board includes the M68HC11, the PSD, and system clock generation circuitry. Including the clock

generator on the daughter board is important to minimize radiated EMI.

2. By placing an edge or row connector on an existing printed circuit board to allow access to a PSD

device on a daughter board. The minimum signals needed include the address/data lines and control

signals (R/W, E, AS, RESET). This requires changing the existing schematic.

3. By redesigning the existing printed circuit board to accommodate the PSD device.

Figure 1

and

Figure 2

are examples of interfacing an M68HC11 to particular PSD devices. Please refer to

the appropriate Motorola data book and to the WSI

PSD Design and Applications Handbook

for more infor-

mation.

Table 2 Recommended Devices

Device EPROM RAM I/O

PSD311C1 32K — 19

PSD311 32K 2048 19

PSD411A1 32K 2048 40

Table 3 Alternative System Configurations

Device ROM RAM EEPROM I/O A/D

Single Chip MC68HC711D3 4K 192 0 32 No

Twin Chip MC68HC11D0 + PSD311C1 32K 192 0 33 No

Single Chip MC68HC711E9/20 12K/20K 512/768 512 38 Yes

Twin Chip MC68HC11A0/1 + PSD311C1 32K 256 0/512 41 Yes

Twin Chip MC68HC11A0/1 + PSD311 32K 2304 0/512 41 Yes

Twin Chip MC68HC11D0 + PSD311C1 32K 192 0 33 No

Twin Chip MC68HC11E0/1 + PSD311C1 32K 512 0/512 41 Yes

Twin Chip MC68HC11ED0 + PSD311C1 32K 512 0 33 No

Single Chip MC68HC11K4 24K 768 640 62 Yes

Twin Chip MC68HC11K0/1 + PSD411A1 32K 2816 0/640 77 Yes

Twin Chip MC68HC11K0/1 + PSD311 32K 816 0/640 56 Yes

Single Chip MC68HC11L6 16K 512 512 46 Yes

Twin Chip MC68HC11L1 + PSD311C1 32K 512 0/512 49 Yes

MOTOROLA AN1237/D

Figure 1 Typical M68HC11 and PSD3XX System

Figure 2 Typical M68HC11 and PSD4XX/5XX System

HC11 PSD3 SCHEM

PC[7:0]

PB[7:0]

R/W

RESET

XTAL

EXTAL

IRQ

XIRQ

MODA

MODB

PA[7:0]

PE[7:0]

PD[7:0]

VRH

VRL

PC[2:0]

PA[7:0]

PB[7:0]

AD[7:0]/A[7:0]

R/W

BHE/PSEN

RESET

A19/CSI

AD[15:8]/A[15:8]

RESET1

VCC

M68HC11 PSD3XX

NOTES:

1. HC11 reset line must be pulled up to VDD.

HC11 PSD4/5 SCHEM

PC[7:0]

PB[7:0]

R/W

RESET

XTAL

EXTAL

IRQ

XIRQ

MODA

MODB

PA[7:0]

PE[7:0]

PD[7:0]

VRH

VRL

PC[2:0]

PD[7:0]

PA[7:0]

AD[7:0]/A[7:0]

R/W

PE1/ALE

RESET

CSI

AD[15:8]/A[15:8]

RESET1

M68HC11 PSD4XX/5XX

PB[7:0]

PE[7:2]

CLOCK

VSTBY

CLKIN

NOTES:

1. HC11 reset line must be pulled up to VDD.

AN1237/D MOTOROLA

CONFIGURE THE M68HC11 FOR EXPANDED MODE OPERATION

M68HC11 operating mode is determined by the logic state of the MODA and MODB pins during system re-

set or power up. To configure the MCU for expanded mode operation, make the reset state of the MODA

pin HIGH by pulling it up to VDD through a pullup resistor.

CONFIGURE THE PSD

PSD software must be used to configure the PSD. There are two different software packages available.

PSD-SILVER software supports the PSD3XX devices and includes the MAPLE and MAPPRO software

modules which run under the DOS platform. MAPLE software is used to configure the PSD chip. It features

simple menu driven commands for selecting different device configurations. It also provides mapping of the

EPROM, SRAM, and chip select outputs into the user's address space, and locates the files to be pro-

grammed into the EPROM segments. MAPPRO enables the user to program PSDs on a WSI MagicPro III®

programmer.

PSDsoft WS7001 or WS7002 software supports the PSD3XX, PSD4XX, and PSD5XX families and runs

under MicroSoft® Windows® (PSD3XX support included in PSDsoft available Q295). It includes PSDabel,

PSD configuration, PSD compiler, PSDsilos III simulator, and PSD programming software. The PSDsoft en-

vironment allows design and simulation of the on-chip PLD logic under Data I/O ABEL®, PSD interface se-

lections to any MCU, configuration of the I/O, and address mapping of the EPROM and SRAM memory,

among other things.

PSD-to-M68HC11 interface configuration is simple and straightforward. Configuration is performed by se-

lecting certain option bits in the PSD software package. For MC68HC11A, C, D, E, and L devices, the PSD

is configured for multiplexed mode. For MC68HC11F, K, and P devices, the PSD is configured for non-mul-

tiplexed mode. For all versions of the M68HC11, the other option bits on the PSD device are set as follows:

R/W and E mode, active high AS (ALE), active low RESET, and combined memory mode. To complete the

configuration process, PSD Ports A and B must be configured as general-purpose I/O, to replace M68HC11

Ports B and C, which are used for address and data lines when the MCU is operating in expanded mode.

For a better understanding of the M68HC11 to PSD interface configuration information, please refer to the

pin descriptions section of the appropriate Motorola data book and to Table 5 and Figure 12 in WSI Appli-

cations Note 011 for PSD3XX devices, and the section beginning with Figure 12 in Applications Note 029

for PSD4XX/5XX devices.

MAKE MEMORY MAP AND I/O PORT SELECTIONS

To convert from an M68HC711 system to a system that uses a ROM-less M68HC11 and a PSD, the content

of the M68HC711 ROM must be transferred to PSD EPROM, and mapped externally. The default state of

the ROMON bit in the CONFIG register of ROM-less M68HC11 devices is zero, so all accesses to the ROM

address space automatically go external. Virtually no change in the MCU address map is required because

PSD EPROM can be mapped anywhere on a block boundary using the address map menu in the PSD soft-

ware.

For example, assume a PSD device with 32 Kbytes of EPROM is selected. The PSD311 has eight blocks

of 4 Kbyte x 8 EPROM. Each block can be mapped on a 4-Kbyte block boundary in the address range as

originally defined in the OTP application. The PSD411A1 has four blocks of 8 Kbyte x 8 EPROM, and each

can be mapped to an 8-Kbyte block boundary. Please refer to the modes and memory section of the appro-

priate Motorola data book, to Figure 32 in WSI Applications Note 011 for the PSD3XX, and to Table 7 in

WSI Applications Note 029 for the PSD4XX/PSD5XX devices.

For PSDs that include an additional 2 Kbyte x 8 SRAM, the SRAM can be mapped anywhere within the ad-

dress space on a 2-Kbyte boundary to extend the SRAM already supplied on the M68HC11.

PSDs also offer from 19 to 40 configurable I/O pins that can replace I/O pins that are used for other purposes

when the M68HC11 operates in expanded mode or enhance the function of the available ports. The pro-

grammable I/O is addressed via an offset from a base address that is selected in the PSD software. These

MOTOROLA AN1237/D

offsets are shown in Table 6 in the PSD3XX data sheets, Tables 21–23 in the PSD4XX data sheet, and in

Tables 29–31 in the PSD5XX data sheet.

For example, the following steps must be performed to replace ports B and C on an M68HC711 with ports

A and B on a PSD311 device.

1. Refer to the appropriate PSD data sheet to determine the correct offsets.

2. Set the CSIOPORT (CSP) base address of the PSD. The base address can be mapped to any

boundary from 256 bytes to 2 Kbytes. In this example, the CSIOPORT base address starts at $2000.

3. Port B on the M68HC11 is mapped to port A on the PSD311. For compatibility with port B on the

M68HC11, which is an output-only port, port A on the PSD311 is set for output. This is accomplished

by writing $FF (output) to the PSD311 port A data direction register, located at $2004 (offset four

from base address).

4. Port C on the M68HC11 is mapped to port B on the PSD311. The direction of the individual I/O pins

in PSD311 port B is determined by the definition in the original OTP application. The direction is set

by writing to $2005 (offset five from base address). To make a pin an input, the appropriate bit in the

5. To write data to PSD311 port A and port B pins, the data must be written to $2006 for port A and to

$2007 for port B. Data from the PSD311 port A and port B pins must be read from $2002 and $2003,

respectively.

Other M68HC11 resources, such as EEPROM, SRAM, vectors, and the control registers are mapped inter-

nally and do not require any memory map redirection.

MODIFY M68HC11 CODE TO ADDRESS PSD MEMORY AND I/O

Change M68HC11 I/O port addresses to match the port address at the appropriate offset from the specified

PSD I/O port base address (CSIOPORT).

INTEGRATE M68HC711 CODE WITH PSD CONFIGURATION DATA

Code that would normally be programmed into M68HC711 EPROM must be merged with PSD configuration

information to create one output file. This is done during the compile procedure in the PSD software. The

single output file is then downloaded to an industry-standard programmer (or the WSI MagicPro III PC-com-

patible programmer) and used to program the PSD device.

PROGRAM THE PSD

The output file (filename.obj) generated from the PSD software compiler is now ready to be programmed

into a device from one of the three PSD families (PSD3XX, PSD4XX, or PSD5XX). A list of programmer

manufacturers that support the PSD devices can be obtained from a WSI sales office or sales representa-

tives. Programmers which support the PSD devices are available from Data I/O, BP Microsystems, and Log-

ical Devices.

CONCLUSION

A single-chip Motorola M68HC711 control system can be quickly and easily converted to a system that uses

a ROM-less M68HC11 and a WSI Programmable MCU peripheral. A small investment in hardware and soft-

ware modification can provide an increase in system memory, expanded I/O, lower power consumption,

greater design flexibility, and lower cost.

AN1237/D MOTOROLA

NOTES

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the suitability of its products for any particular purpose, nor does Motorola assume any liability arising out of the application or use of any product or circuit, and

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