NXP TWR-KE18F

Overview

The TWR-KE18F is a development board for NXP Kinetis KE1xF 32-bit MCU-based platforms. The onboard OpenSDAv2 serial and debug adapter, running an open source bootloader, offers options for serial communication, flash programming, and run-control debugging.

TWR-KE18F

TWR-KE18F (Credit: NXP)

Hardware

  • MKE18F512VLL16 MCU (up to 168 MHz, 512 KB flash memory, 64 KB RAM, and 100 Low profile Quad Flat Package (LQFP))
  • 3.3 V or 5 V MCU operation
  • 6-axis FXOS8700CQ digital accelerometer and magnetometer
  • RGB LED
  • Four user LEDs
  • Two user push-buttons
  • Potentiometer
  • Thermistor
  • Infrared port (IrDA)
  • CAN pin header
  • Flex I/O pin header

For more information about the KE1xF SoC and the TWR-KE18F board, see these NXP reference documents:

Supported Features

The twr_ke18f 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
FLASH on-chip soc flash
RTC on-chip rtc
I2C(M) on-chip i2c
SENSOR off-chip fxos8700 polling; trigger supported with H/W mods explained below;
SPI(M) on-chip spi
ADC on-chip adc
CAN on-chip can
WDT on-chip watchdog
PWM on-chip pwm

The default configuration can be found in the defconfig file: boards/arm/twr_ke18f/twr_ke18f_defconfig.

Other hardware features are not currently supported by the port.

System Clock

The KE18 SoC is configured to use the 8 MHz external oscillator on the board with the on-chip PLL to generate a 120 MHz system clock.

Serial Port

The KE18 SoC has three UARTs. UART0 is configured for the console. The remaining UARTs are not used.

Accelerometer and magnetometer

The TWR-KE18F board by default only supports polling the FXOS8700 accelerometer and magnetometer for sensor values (CONFIG_FXOS8700_TRIGGER_NONE=y).

In order to support FXOS8700 triggers (interrupts) the 0 ohm resistors R47 and and R57 must be mounted on the TWR-KE18F board. The devicetree must also be modified to describe the FXOS8700 interrupt GPIOs:

/dts-v1/;

&fxos8700 {
        int1-gpios = <&gpioa 14 0>;
        int2-gpios = <&gpioc 17 0>;
};

Finally, a trigger option must be enabled in Kconfig (either FXOS8700_TRIGGER_GLOBAL_THREAD=y or FXOS8700_TRIGGER_OWN_THREAD=y).

Programming and Debugging

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.

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 J2.

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 twr_ke18f 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-xxx-gxxxxxxxxxxxx *****
Hello World! twr_ke18f

Debugging

Here is an example for the Hello World application.

# From the root of the zephyr repository
west build -b twr_ke18f samples/hello_world
west debug

Open a serial terminal, step through the application in your debugger, and you should see the following message in the terminal:

***** Booting Zephyr OS v1.14.0-xxx-gxxxxxxxxxxxx *****
Hello World! twr_ke18f