NXP FRDM-KW41Z

Overview

The FRDM-KW41Z is a development kit enabled by the Kinetis® W series KW41Z/31Z/21Z (KW41Z) family built on ARM® Cortex®-M0+ processor with integrated 2.4 GHz transceiver supporting Bluetooth® Smart/Bluetooth® Low Energy (BLE) v4.2, Generic FSK, IEEE® 802.15.4 and Thread.

The FRDM-KW41Z kit contains two Freedom boards that can be used as a development board or a shield to connect to a host processor. The FRDM-KW41Z is form-factor compatible with the Arduino™ R3 pin layout for more expansion options.

The FRDM-KW41Z highly-sensitive, optimized 2.4 GHz radio features a PCB F-antenna which can be bypassed to test via SMA connection, multiple power supply options, push/capacitive touch buttons, switches, LEDs and integrated sensors.

Hardware

Can be configured as Host or Shield for connection to Host Processor
Supports all DC-DC configurations (Buck, Boost, Bypass)
PCB inverted F-type antenna
SMA RF Connector
RF regulatory certified
Serial Flash for OTA firmware upgrades
On board NXP FXOS8700CQ digital sensor, 3D Accelerometer ( ±2g/ ±4g/ ±8g) + 3D Magnetometer
OpenSDA and JTAG debug

For more information about the KW41Z SoC and FRDM-KW41Z board:

Supported Features

The frdm_kw41z 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
COUNTER	on-chip	rtc
GPIO	on-chip	gpio
I2C	on-chip	i2c
SPI	on-chip	spi
ADC	on-chip	adc
UART	on-chip	serial port-polling; serial port-interrupt
FLASH	on-chip	soc flash
SENSOR	off-chip	fxos8700 polling: fxos8700 trigger
PWM	on-chip	tpm
TRNG	on-chip	entropy
FTFA	on-chip	flash programming

The default configuration can be found in the defconfig file:

boards/arm/frdm_kw41z/frdm_kw41z_defconfig

Other hardware features are not currently supported by the port.

Connections and IOs

The KW41Z SoC has three pairs of pinmux/gpio controllers, but only two are currently enabled (PORTA/GPIOA and PORTC/GPIOC) for the FRDM-KW41Z board.

Name	Function	Usage
PTC1	GPIO	Red LED / FXOS8700 INT1
PTA19	GPIO	Green LED
PTA18	GPIO	Blue LED
PTB2	ADC	ADC0 channel 3
PTC2	I2C1_SCL	I2C / FXOS8700
PTC3	I2C1_SDA	I2C / FXOS8700
PTC4	GPIO	SW3
PTC5	GPIO	SW4
PTC6	LPUART0_RX	UART Console
PTC7	LPUART0_TX	UART Console
PTC16	SPI0_SCK	SPI
PTC17	SPI0_SOUT	SPI
PTC18	SPI0_SIN	SPI
PTC19	SPI0_PCS0	SPI

System Clock

The KW41Z SoC is configured to use the 32 MHz external oscillator on the board with the on-chip FLL to generate a 40 MHz system clock.

Serial Port

The KW41Z SoC has one UART, which is used for the console.

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.

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 FRDM-KW41Z 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 FRDM-KW41Z 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_kw41z 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 J6.

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_kw41z 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_kw41z

Debugging