Freescale Semiconductor
User’s Guide
© 2013 Freescale Semiconductor, Inc. All rights reserved.
1 Overview
The Freescale Freedom development platform is a set of
software and hardware tools for evaluation and
development. It’s ideal for the rapid prototyping of
microcontroller-based applications. The Freescale Freedom
KL26Z hardware (FRDM-KL26Z) is a capable and
cost-effective design featuring a Kinetis L series
microcontroller, the industry’s first microcontroller built on
the ARM® Cortex™-M0+ core.
FRDM-KL26Z can be used to evaluate the KL16 and KL26
Kinetis L series devices. It features a KL26Z128VLH4, a
device boasting a maximum operating frequency of 48MHz,
128KB of flash, a full-speed USB controller, and numerous
analog and digital peripherals. The FRDM-KL26Z hardware
is form-factor compatible with the Arduino™ R3 pin layout,
providing a broad range of expansion board options. The
on-board interfaces include an RGB LED, a 6-axis digital
sensor (combining a 3D accelerometer and 3D
magnetometer), ambient light sensor, and a capacitive touch
slider.
The FRDM-KL26Z features the Freescale open standard
embedded serial and debug adapter known as OpenSDA.
Doc Number: FRDMKL26ZUG
Rev. 0, 10/2013
Contents
1. Overview . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
2. Reference documents . . . . . . . . . . . . . . . . . . . . . . . . . 2
3. Getting started . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2
4. FRDM-KL26Z hardware overview . . . . . . . . . . . . . . 2
5. FRDM-KL26Z hardware description . . . . . . . . . . . . . 5
FRDM-KL26Z User’s Guide
by Freescale Semiconductor, Inc.
FRDM-KL26Z User’s Guide, Rev. 0
2Freescale Semiconductor
Reference documents
This circuit offers several options for serial communications, flash programming and run-control
debugging.
2 Reference documents
The table below provides a list of reference documents for the FRDM-KL26Z hardware. All of these
documents are available online at www.freescale.com/FRDM-KL26Z.
3 Getting started
See the FRDM-KL26Z Quick Start Package for step-by-step instructions to get started with the
FRDM-KL26Z. See the Jump Start Your Design section on www.freescale.com/FRDM-KL26Z for the
Quick Start Package and software lab guides.
4 FRDM-KL26Z hardware overview
The features of the FRDM-KL26Z include:
• MKL26Z128VLH4 in a 64 LQFP package
• Capacitive touch slider
• FXOS8700CQ accelerometer and magnetometer
• Tri-color (RGB) LED
• Ambient light sensor
• User push button
• Flexible power supply options – USB, coin cell battery, external source
• Battery-ready, power-measurement access points
• Easy access to MCU I/O via Arduino™ R3 compatible I/O connectors
• Programmable OpenSDA debug interface with multiple applications available including:
— Mass storage device flash programming interface
— P&E Debug interface provides run-control debugging and compatibility with IDE tools
Table 1. FRDM-KL26Z reference documents
Filename Description
FRDM-KL26Z Quick Start Package Quick Start Guide and supporting files for getting started with the FRDM-KL26Z
FRDM-KL26Z User’s Guide This document—overview and detailed information for the FRDM-KL26Z
hardware
FRDM-KL26Z Pinouts Spreadsheet of pin connections for all MCU pins. Includes pinout for the I/O
headers, Arduino R3 compatibility chart, and OpenSDA MCU pinout.
FRDM-KL26Z Schematics PDF schematics for the FRDM-KL26Z hardware
FRDM-KL26Z Design Package Zip file containing all design source files for the FRDM-KL26Z hardware
OpenSDA User’s Guide Overview and instructions for use of the OpenSDA embedded debug circuit
FRDM-KL26Z User’s Guide, Rev. 0
Freescale Semiconductor 3
FRDM-KL26Z hardware overview
— CMSIS-DAP interface: new ARM standard for embedded debug interface
— Data logging application
Figure 1 shows a block diagram of the FRDM-KL26Z design. The primary components and their
placement on the hardware assembly are pointed out in Figure 2.
Figure 1. FRDM-KL26Z block diagram
FRDM-KL26Z User’s Guide, Rev. 0
4Freescale Semiconductor
FRDM-KL26Z hardware overview
Figure 2. FRDM-KL26Z feature call-outs
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FRDM-KL26Z User’s Guide, Rev. 0
Freescale Semiconductor 5
FRDM-KL26Z hardware description
5FRDM‐KL26Zhardwaredescription
5.1 Power supply
There are multiple power supply options on the FRDM-KL26Z. It can be powered from either of the USB
connectors, the VIN pin on the I/O header, an on-board coin cell battery, or an off-board 1.71-3.6V supply
from the 3.3V pin on the I/O header. The USB and VIN supplies are regulated on-board using a 3.3V linear
regulator to produce the main power supply. The other two sources are not regulated on-board. Table 2
provides the operational details and requirements for the power supplies.
Table 2. Powersupplyrequirements
Note that the OpenSDA circuit is only operational when a USB cable is connected and supplying power
to J10. However, protection circuitry is in place to allow multiple sources to be powered at once.
Figure 3 shows the schematic drawing for the power supply inputs and the on-board voltage regulator.
Figure 3. Power supply schematic
In addition, regulated power can be supplied to J3 pin 10 from an external source through P5-9V_VIN by
populating the board with an optional voltage regulator, e.g. a 7805 style regulator in a TO-220 package,
thus providing a high current supply to external devices. To prevent voltage sag under a high load, C23,
Supply Source Valid Range OpenSDA Operational? Regulated on-board?
OpenSDA USB (J7) 5V Yes Yes
KL26Z USB (J5) 5V No Yes
Vin 4.3-9V No Yes
3.3V pin 1.71-3.6V No No
Coin cell battery 1.71-3.6V No No
FRDM-KL26Z User’s Guide, Rev. 0
6Freescale Semiconductor
FRDM-KL26Z hardware description
C24, C25 & C28 should be populated with appropriately sized capacitors to match the regulator chosen.
See Figure 4.
Figure 4. Optional voltage regulator schematic
Table 3. FRDM-KL26Z power supplies
Power
Supply Name Description
P5-9V_VIN Power supplied from the Vin pin of the I/O headers (J3 pin 16)
P5V_SDA Power supplied from the OpenSDA USB connector (J10). A Schottky diode provides back drive
protection.
P5V_KL26Z Power supplied from the KL26Z USB connector (J6). A Schottky diode provides back drive protection
P3V3_VREG Regulated 3.3V supply. Sources power to the P3V3 supply rail with an optional back drive protection
Schottky diode.1 2
P3V3_BATT Coin cell battery supply voltage. Sources power to the P3V3 supply rail with the option of adding a back
drive protection Schottky diode.3
P3V3 Main supply rail for the FRDM-KL26Z assembly. May be sourced from P3V3_VREG, P3V3_BATT, or
directly from the I/O headers (J3 pin 8).
P3V3_KL26Z KL26Z MCU supply. Header J5 provides a convenient means for energy consumption measurements.4
P3V3_SDA OpenSDA circuit supply. Header J15 provides a convenient means for energy consumption
measurements.4
P5V_USB Nominal 5V supplied to the I/O headers (J3 pin 10). Sourced from either the P5V_KL26Z or P5V_SDA
supply through a back drive protection Schottky diode.
FRDM-KL26Z User’s Guide, Rev. 0
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FRDM-KL26Z hardware description
5.2 Serial and debug adapter (OpenSDA)
OpenSDA is an open standard serial and debug adapter. It bridges serial and debug communications
between a USB host and an embedded target processor as shown in Figure 5. The hardware circuit is based
on a Freescale Kinetis K20 family microcontroller (MCU) with 128 KB of embedded flash and an
integrated USB controller. OpenSDA features a mass storage device (MSD) bootloader, which provides a
quick and easy mechanism for loading different OpenSDA applications such as flash programmers,
run-control debug interfaces, serial-to-USB converters, and more. See the OpenSDA User’s Guide for
more details.
Figure 5. OpenSDA high-level block diagram
OpenSDA is managed by a Kinetis K20 MCU built on the ARM® Cortex™-M4 core. The OpenSDA
circuit includes a status LED (D8) and a pushbutton (SW2). The pushbutton asserts a reset signal to the
KL26Z target MCU. It can also be used to place the OpenSDA circuit into Bootloader mode. OpenSDA
MCU RESET can be isolated from SW2 by cutting the trace between pins on J13. SPI and GPIO signals
1Bydefaultthelinearregulator,U1,isa3.3Voutputregulator.However,thisisacommonfootprintthatwouldallow
theusertomodifytheassemblytoutilizeanalternativedevicesuchasa1.8Vor2.5Vregulator.TheKL26Z
microcontrollerhasanoperatingrangeof1.71Vto3.6V.
2D2isbypassedbyJ14.Bydefault,thepinsofJ14areshortedtogether,toreducethevoltagedropacrossD2.Touse
D2,cutthetracebetweenthepinsofJ14.
3Ifacoincellbatteryistobeused,addasmallamountofsoldertothecoincellgroundpadbeforeaddingthebattery
holder.Also,itisrecommendedtopopulateD1asaprotectiondiodewhenusingacoincellbattery.
4J5andJ15arenotpopulatedbydefault.Thetwopinsoftheseheadersareinparallelwith0Ωresistors.Inaddition,
J5isalsoinparallelwitha10Ωresistor.TomeasuretheenergyconsumptionoftheKL26Z,eitheravoltmeteroran
ammetermaybeused.Touseavoltmeter,R3(0Ω)mustberemovedbeforeconnectingthevoltmeterprobestothe
pinsofJ5.BothR3andR2(10Ω)mustberemovedtomeasurecurrentwithanammeter.FortheOpenSDAMCU,
energyconsumptioncanbemeasuredbyremovingR4(0Ω)andconnectingammeterprobestothepinsofJ15.
FRDM-KL26Z User’s Guide, Rev. 0
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FRDM-KL26Z hardware description
provide an interface to the SWD debug port of the KL26Z. Additionally, signal connections are available
to implement a UART serial channel. The OpenSDA circuit receives power when the USB connector J10
is plugged into a USB host.
5.2.1 Debug interface
Signals with SPI and GPIO capability are used to connect directly to the SWD of the KL26Z. These
signals are also brought out to a standard 10-pin (0.05”) Cortex Debug connector (J7). It is possible to
isolate the KL26Z MCU from the OpenSDA circuit and use J7 to connect to an off-board MCU. To
accomplish this, cut the trace on the bottom side of the PCB that connects J8 pin 1 to J8 pin 2. This will
disconnect the SWD_CLK pin to the KL26Z so that it will not interfere with the communications to an
off-board MCU connected to J7.
Figure 6. SWD debug connector
Note that J7 is not populated by default. A Samtec FTSH-105-02-F-D or compatible connector can be
added to the J7 through-hole connector. A mating cable, such as a Samtec FFSD IDC cable, can then be
used to connect from the OpenSDA of the FRDM-KL26Z to an off-board SWD connector.
5.2.2 Virtual serial port
A serial port connection is available between the OpenSDA MCU and pins PTA1 and PTA2 of the KL26Z.
Several of the default OpenSDA Applications provided by Freescale, including the MSD Flash
Programmer and the P&E Debug Application, provide a USB communications device class (CDC)
interface that bridges serial communications between the USB host and this serial interface on the KL26Z.
5.3 KL26Z microcontroller
The target microcontroller of the FRDM-KL26Z is the KL26Z128VLH4, a Kinetis L series device in a 64
LQFP package. The KL26Z MCU features include:
FRDM-KL26Z User’s Guide, Rev. 0
Freescale Semiconductor 9
FRDM-KL26Z hardware description
• 32-bit ARM Cortex-M0+ core
— Up to 48 MHz operation
— Single-cycle fast I/O access port
• Memories
— 128 KB flash
—16 KB SRAM
• System integration
— Power management and mode controllers
— Low-leakage wakeup unit
— Bit manipulation engine for read-modify-write peripheral operations
— Direct memory access (DMA) controller
— Computer operating properly (COP) Watchdog timer
•Clocks
— Clock generation module with FLL and PLL for system and CPU clock generation
— 4 MHz and 32 kHz internal reference clock
— System oscillator supporting external crystal or resonator
— Low-power 1kHz RC oscillator for RTC and COP watchdog
• Analog peripherals
— 16-bit SAR ADC w/ DMA support
— 12-bit DAC w/ DMA support
— High speed comparator
• Communication peripherals
— Two 16-bit Serial Peripheral Interfaces (SPI)
— USB dual-role controller with built-in FS/LS transceiver
— USB voltage regulator
—Two I
2C modules
— One low-power UART and two standard UART modules
— One I2S module
•Timers
— One 6-channel Timer/PWM module
—Two 2-channel Timer/PWM modules
— 2-channel Periodic Interrupt Timer (PIT)
— Real time clock (RTC)
— Low-power Timer (LPTMR)
— System tick timer
• Human-Machine Interfaces (HMI)
— General purpose input/output controller
FRDM-KL26Z User’s Guide, Rev. 0
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FRDM-KL26Z hardware description
— Capacitive touch sense input interface hardware module
5.3.1 Clock source
The Kinetis KL26 microcontrollers feature an on-chip oscillator compatible with three ranges of input
crystal or resonator frequencies: 32-40 kHz (low freq. mode), 3-8 MHz (high frequency mode, low range)
and 8-32 MHz (high frequency mode, high range). The KL26Z128 on the FRDM-KL26Z is clocked from
an 8 MHz crystal.
5.3.2 USB interface
The Kinetis KL26 microcontrollers feature a dual-role USB controller with on-chip full-speed and
low-speed transceivers. The USB interface on the FRDM-KL26Z is configured as a full-speed USB
device. J6 is the USB connector for this interface.
Figure 7. USB connector schematic
In order to enable USB host functionality on the FRDM-KL26Z, it is necessary to populate J9 and R8 as
shown in Figure 7. However, there is no electrical protection provided. Use the USB host functionality at
your own risk.
FRDM-KL26Z User’s Guide, Rev. 0
Freescale Semiconductor 11
FRDM-KL26Z hardware description
5.3.3 Serial port
The primary serial port interface signals are PTA1 and PTA2. These signals are connected to both the
OpenSDA and to the J1 I/O connector. Note that the OpenSDA connection can be isolated from J1 by
removing R13 & R14, if required.
5.3.4 Reset
The PTA20/RESET signal on the KL26Z128 is connected externally to a pushbutton, SW2, and also to the
OpenSDA circuit. However, J13 has been provided to isolate the OpenSDA MCU from SW2. Isolating the
RESET line allows a more accurate measurement of the target device’s power consumption in low-power
modes. The reset button can be used to force an external reset event in the target MCU. The reset button
can also be used to force the OpenSDA circuit into bootloader mode. See Section 5.2, “Serial and debug
adapter (OpenSDA), for more details.
5.3.5 Debug
The sole debug interface on all Kinetis L Series devices is a serial wire debug (SWD) port. The primary
controller of this interface on the FRDM-KL26Z is the onboard OpenSDA circuit (see Section 5.2, “Serial
and debug adapter (OpenSDA)). However, an unpopulated 10-pin (0.05”) Cortex Debug connector, J7,
provides access to the SWD signals. The Samtec FTSH-105-02-F-D or compatible connector can be added
to the J7 through-hole debug connector to allow for an external debug cable to be connected.
5.4 Capacitive touch slider
Two Touch Sense Input (TSI) signals, TSI0_CH9 and TSI0_CH10, are connected to capacitive electrodes
configured as a touch slider. Freescale’s Touch Sense Software (TSS) provides a software library for
implementing the capacitive touch slider.
5.5 6-axis accelerometer and magnetometer
A Freescale FXOS8700CQ low-power, six-axis accelerometer and magnetometer is interfaced through an
I2C bus and two GPIO signals as shown in Table 4. By default, the I2C address is 0x1D (SA0 pulled high).
Table 4. Accelerometer signal connections
FX0S8700CQ KL26Z128
SCL PTE24
SDA PTE25
INT1 PTD0
INT2 PTD1
FRDM-KL26Z User’s Guide, Rev. 0
12 Freescale Semiconductor
FRDM-KL26Z hardware description
Figure 8. FXOS8700CQ schematic diagram
5.6 RGB LED
Three PWM-capable signals are connected to a red, green, blue LED, D7. The signal connections are
shown in Table 5.
Table 5. RGB LED signal connections
Figure 9. RGB LED schematic diagram
RGB LED KL26Z128
Red cathode PTE29
Green cathode PTE31
Blue cathode PTD51
1PTD5 is also connected to the I/O header on J2 pin 10 (also known as D13).
FRDM-KL26Z User’s Guide, Rev. 0
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FRDM-KL26Z hardware description
5.7 Ambientlightsensor
An ambient light sensor is connected to ADC0_SE3 (PTE22). This sensor may be isolated from PTE22 by
removing R36.
5.8 Input/Output connectors
The KL26Z128VLK4 microcontroller is packaged in a 64-pin LQFP. Some pins are utilized in on-board
circuitry, but many are directly connected to one of four I/O headers.
The pins on the KL26Z microcontroller are named for their general purpose input/output port pin function.
For example, the 1st pin on Port A is referred to as PTA1. The I/O connector pin names are given the same
name as the KL26Z pin connected to it, where applicable.
FRDM-KL26Z User’s Guide, Rev. 0
14 Freescale Semiconductor
FRDM-KL26Z hardware description
Note that all pinout data is available in spreadsheet format in FRDM-KL26Z Pinouts. See Section 2,
“Reference documents” for details.
5.9 Analog reference voltage
The onboard ADC of the KL26Z128VLH4 MCU uses the Reference Voltage High (VREFH) and
Reference Voltage Low (VREFL) pins to set high and low voltage references for the analog modules. On
the FRDM-KL26Z, by default VREFH is attached to P3V3_KL26Z (3.3V Supply). VREFL is connected
to GND. Figure 10 illustrates this circuitry.
Figure 10. FRDM-KL26Z VREFH circuit schematic
If desired, VREFH can use a VDDA independent reference by adding R11 and a Zener diode (D6). R10
(0 Ω resistor) must be removed when implementing this option. Alternatively, VREFH can be attached to
an external source through AREF by removing R10 and populating R9 with a 0 Ω resistor.
5.10 Arduino compatibility
The I/O headers on the FRDM-KL26Z are arranged to allow compatibility with peripheral boards (known
as shields) that connect to Arduino™ and Arduino-compatible microcontroller boards. The outer rows of
pins (the even numbered pins) on the headers share the same mechanical spacing and placement as the I/O
headers on the Arduino Revision 3 (R3) standard.
FRDM-KL26Z User’s Guide, Rev. 0
Freescale Semiconductor 15
FRDM-KL26Z hardware description
Refer to the FRDM-KL26Z Pinouts spreadsheet for a compatibility chart showing how all the functions of
the KL26Z signals on the I/O connectors map to the pin functions available on the Arduino Uno R3.
Document Number: FRDMKL26ZUG
Rev. 0
10/2013
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