NXP 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 configuration supports the following hardware features:

Interface	Controller	Driver/Component
NVIC	on-chip	nested vector interrupt controller
SYSTICK	on-chip	systick
PINMUX	on-chip	pinmux
GPIO	on-chip	gpio
UART	on-chip	serial port-polling; serial port-interrupt
I2C	on-chip	i2c
SPI	on-chip	spi
ADC	on-chip	adc
FLASH	on-chip	soc flash

The default configuration can be found in the defconfig file:

boards/arm/frdm_kl25z/frdm_kl25z_defconfig

Other hardware features are not currently supported by the port.

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
PTC4	SPI0_PSC0	SPI
PTC5	SPI0_SCK	SPI
PTC6	SPI0_MOSI	SPI
PTC7	SPI0_MISO	SPI

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.

Programming and Debugging¶

The FRDM-KL25Z includes the NXP OpenSDA serial and debug adapter built into the board to provide debugging, flash programming, and serial communication over USB.

To use the pyOCD tools with OpenSDA, follow the instructions in the pyOCD page using the DAPLink FRDM-KL25Z Firmware. The pyOCD tools are the default for this board, therefore it is not necessary to set OPENSDA_FW=daplink explicitly when programming and debugging.

With these mechanisms, applications for the frdm_kl25z board configuration can be built and flashed in the usual way (see Build an Application and Run an Application for more details).

To use the Segger J-Link tools with OpenSDA, follow the instructions in the Segger J-Link page using the Segger J-Link OpenSDA V2.1 Firmware. The Segger J-Link tools are not the default for this board, therefore it is necessary to set OPENSDA_FW=jlink explicitly in the environment before programming and debugging.

Flashing¶

This example uses the Hello World sample with the pyOCD tools.

# On Linux/macOS
cd $ZEPHYR_BASE/samples/hello_world
mkdir build && cd build

# On Windows
cd %ZEPHYR_BASE%\samples\hello_world
mkdir build & cd build

# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=frdm_kl25z ..

# Now run ninja on the generated build system:
ninja flash

Open a serial terminal (minicom, putty, etc.) with the following settings:

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

Reset the board and you should be able to see on the corresponding Serial Port the following message:

Hello World! arm

Debugging¶

You can debug an application in the usual way. Here is an example for the Hello World application.

# On Linux/macOS
cd $ZEPHYR_BASE/samples/hello_world
# If you already made a build directory (build) and ran cmake, just 'cd build' instead.
mkdir build && cd build

# On Windows
cd %ZEPHYR_BASE%\samples\hello_world
# If you already made a build directory (build) and ran cmake, just 'cd build' instead.
mkdir build & cd build

# Use cmake to configure a Ninja-based build system:
cmake -GNinja -DBOARD=frdm_kl25z ..

# Now run ninja on the generated build system:
ninja debug