FRDM-KL25Z

Overview

The Freedom KL25Z is an ultra-low-cost development platform for Kinetis® L Series KL1x (KL14/15) and KL2x (KL24/25) MCUs built on ARM® Cortex®-M0+ processor.

The FRDM-KL25Z features include easy access to MCU I/O, battery-ready, low-power operation, a standard-based form factor with expansion board options and a built-in debug interface for flash programming and run-control.

Hardware

MKL25Z128VLK4 MCU @ 48 MHz, 128 KB flash, 16 KB SRAM, USB OTG (FS), 80LQFP
On board capacitive touch “slider”, MMA8451Q accelerometer, and tri-color LED
OpenSDA debug interface

For more information about the KL25Z SoC and FRDM-KL25Z board:

Supported Features

The frdm_kl25z board supports the hardware features listed below.

on-chip / on-board: Feature integrated in the SoC / present on the board.
2 / 2: Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files.
vnd,foo: Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.

frdm_kl25z

/

mkl25z4

Type	Location	Description	Compatible
CPU	on-chip	ARM Cortex-M0+ CPU1	`arm,cortex-m0+`
ADC	on-chip	Kinetis ADC161	`nxp,kinetis-adc16`
Clock control	on-chip	NXP Kinetis Multipurpose Clock generator (MCG) IP node1	`nxp,kinetis-mcg`
	on-chip	Kinetis System Integration Module (SIM) IP node1	`nxp,kinetis-sim`
	on-chip	Generic fixed factor clock provider2	`fixed-factor-clock`
Flash controller	on-chip	NXP Kinetis Flash Memory Module A (FTFA)1	`nxp,kinetis-ftfa`
GPIO & Headers	on-chip	Kinetis GPIO3 2	`nxp,kinetis-gpio`
GPIO & Headers	on-board	GPIO pins exposed on Arduino Uno (R3) headers1	`arduino-header-r3`
I2C	on-chip	Kinetis I2C1 1	`nxp,kinetis-i2c`
Input	on-board	Group of GPIO-bound input keys1	`gpio-keys`
Interrupt controller	on-chip	ARMv6-M NVIC (Nested Vectored Interrupt Controller) controller1	`arm,v6m-nvic`
LED	on-board	Group of GPIO-controlled LEDs1	`gpio-leds`
MTD	on-chip	Flash node1	`soc-nv-flash`
Pin control	on-chip	NXP PORT Pin Controller5	`nxp,port-pinmux`
Pin control	on-chip	NXP PORT Pin Controller1	`nxp,port-pinctrl`
Sensors	on-board	FXOS8700 6-axis accelerometer/magnetometer sensor1	`nxp,fxos8700`
Serial controller	on-chip	Kinetis LPSCI UART1	`nxp,kinetis-lpsci`
SRAM	on-chip	Generic on-chip SRAM1	`mmio-sram`
Timer	on-chip	ARMv6-M System Tick1	`arm,armv6m-systick`
USB	on-chip	NPX Kinetis USBFSOTG Controller in device mode1	`nxp,kinetis-usbd`

Connections and IOs

The KL25Z SoC has five pairs of pinmux/gpio controllers, and all are currently enabled (PORTA/GPIOA, PORTB/GPIOB, PORTC/GPIOC, PORTD/GPIOD, and PORTE/GPIOE) for the FRDM-KL25Z board.

Name	Function	Usage
PTB2	ADC	ADC0 channel 12
PTB18	GPIO	Red LED
PTB19	GPIO	Green LED
PTD1	GPIO	Blue LED
PTA1	UART0_RX	UART Console
PTA2	UART0_TX	UART Console
PTE24	I2C0_SCL	I2C
PTE25	I2C0_SDA	I2C

System Clock

The KL25Z SoC is configured to use the 8 MHz external oscillator on the board with the on-chip FLL to generate a 48 MHz system clock.

Serial Port

The KL25Z UART0 is used for the console.

USB

The KL25Z SoC has a USB OTG (USBOTG) controller that supports both device and host functions through its mini USB connector (USB KL25Z). Only USB device function is supported in Zephyr at the moment.

Programming and Debugging

The frdm_kl25z board supports the runners and associated west commands listed below.

	flash	debug	attach	debugserver	rtt
jlink	✅	✅	✅	✅	✅
linkserver	✅ (default)	✅ (default)	✅	✅
pyocd	✅	✅	✅	✅	✅

Build and flash applications as usual (see Building an Application and Run an Application for more details).

Configuring a Debug Probe

A debug probe is used for both flashing and debugging the board. This board is configured by default to use the OpenSDA DAPLink Onboard Debug Probe.

Early versions of this board have an outdated version of the OpenSDA bootloader and require an update. Please see the DAPLink Bootloader Update page for instructions to update from the CMSIS-DAP bootloader to the DAPLink bootloader.

Option 1: Linkserver: OpenSDA DAPLink Onboard Debug Probe (Recommended)

Install the LinkServer Debug Host Tools and make sure they are in your search path. LinkServer works with the CMSIS-DAP debug firmware. Please follow the instructions on OpenSDA DAPLink Onboard Debug Probe and select the latest revision of the firmware image.

Linkserver is the default for this board, west flash and west debug will call the linkserver runner.
west flash
west debug

Option 2: OpenSDA J-Link Onboard Debug Probe 

Install the J-Link Debug Host Tools and make sure they are in your search path.

Follow the instructions in OpenSDA J-Link Onboard Debug Probe to program the OpenSDA J-Link FRDM-KL25Z Firmware.

Add the arguments -DBOARD_FLASH_RUNNER=jlink and -DBOARD_DEBUG_RUNNER=jlink when you invoke west build to override the default runner from pyOCD to J-Link:

# From the root of the zephyr repository
west build -b frdm_kl25z samples/hello_world -- -DBOARD_FLASH_RUNNER=jlink -DBOARD_DEBUG_RUNNER=jlink

Note:

The runners supported by NXP are LinkServer and JLink. pyOCD is another potential option, but NXP does not test or support the pyOCD runner.

Configuring a Console

Regardless of your choice in debug probe, we will use the OpenSDA microcontroller as a usb-to-serial adapter for the serial console.

Connect a USB cable from your PC to J7.

Use the following settings with your serial terminal of choice (minicom, putty, etc.):

Speed: 115200
Data: 8 bits
Parity: None
Stop bits: 1

Flashing

Here is an example for the Hello World application.

# From the root of the zephyr repository
west build -b frdm_kl25z samples/hello_world
west flash

Open a serial terminal, reset the board (press the SW1 button), and you should see the following message in the terminal:

***** Booting Zephyr OS v1.14.0-rc1 *****
Hello World! frdm_kl25z

Debugging