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.

FRDM-KL25Z

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
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

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

# If you already made a build directory (build) and ran cmake, just 'cd build' instead.

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

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