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.

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
DAC	on-chip	dac
ACMP	on-chip	analog comparator

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.

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

Install the pyOCD Debug Host Tools and make sure they are in your search path.

Follow the instructions in OpenSDA DAPLink Onboard Debug Probe to program the OpenSDA DAPLink TWR-KE18F Firmware.

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 Firmware for TWR-KE18F.

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 twr_ke18f samples/hello_world -- -DBOARD_FLASH_RUNNER=jlink -DBOARD_DEBUG_RUNNER=jlink

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