RAK4631

Overview

RAK4631 is a WisBlock Core module for RAK WisBlock. It extends the WisBlock series with a powerful Nordic nRF52840 MCU that supports Bluetooth 5.0 (Bluetooth Low Energy) and the newest LoRa transceiver from Semtech, the SX1262. The Semtech SX1262 has compared to the older SX127x series a lower power consumption at the same TX power. This makes the RAK4631 an ultra-low power communication solution. RAK4631 can be comfortably programmed with ZephyrRTOS.

RAK4631-NRF52840

Hardware

To use a RAK4631, you need at least a WisBlock Base to plug the module in. WisBlock Base is the power supply for the RAK4631 module and has the programming/debug interface.

  • nRF52840 ARM Cortex-M4F Processor

  • 64 MHz CPU clock

  • 1 Micro-AB USB OTG host/device

  • Semtech SX1262 low power high range LoRa transceiver

  • iPEX connectors for the LORA antenna and BLE antenna.

  • Multiple interfaces, I2C, UART, GPIO, ADC

  • 2 user LEDs on RAK5005 mother Board

  • Powered by either Micro USB, 3.7V rechargeable battery or a 5V Solar Panel Port

Supported Features

The rak4631_nrf52840 board configuration supports the following hardware features:

Interface

Controller

Driver/Component

ADC

on-chip

adc

CLOCK

on-chip

clock_control

FLASH

on-chip

flash

GPIO

on-chip

gpio

I2C(M)

on-chip

i2c

MPU

on-chip

arch/arm

NVIC

on-chip

arch/arm

PWM

on-chip

pwm

RADIO

on-chip

Bluetooth, ieee802154

RADIO

on-board

LoRa (SX1262)

RTC

on-chip

system clock

SPI(M/S)

on-chip

spi

UART

on-chip

serial

USB

on-chip

usb

WDT

on-chip

watchdog

The default board configuration can be found in the defconfig file:

boards/arm/rak4631_nrf52840/rak4631_nrf52840_defconfig

Connections and IOs

LED

  • LED1 (green) = P1.3

  • LED2 (blue) = P1.4

Programming and Debugging

The RAK4631 board shall be connected to a Segger Embedded Debugger Unit J-Link OB. This provides a debug interface to the NRF52840 chip. You can use JLink to communicate with the NRF52840.

Flashing

  1. Download JLink from the Segger JLink Downloads Page 1. Go to the section “J-Link Software and Documentation Pack” and install the “J-Link Software and Documentation pack for Linux”. The application JLinkExe needs to be accessible from your path.

  2. Run your favorite terminal program to listen for output. Under Linux the terminal should be /dev/ttyACM0. For example:

    $ minicom -D /dev/ttyACM0 -o

    The -o option tells minicom not to send the modem initialization string. Connection should be configured as follows:

    • Speed: 115200

    • Data: 8 bits

    • Parity: None

    • Stop bits: 1

#. Connect the RAK4631 board to your host computer using the USB debug port. Then build and flash the Hello World application.

# From the root of the zephyr repository
west build -b rak4631_nrf52840 samples/hello_world
west flash

You should see “Hello World! rak4631_nrf52840” in your terminal.

Debugging

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

# From the root of the zephyr repository
west build -b rak4631_nrf52840 samples/hello_world
west debug