96Boards WisTrio


96Boards WisTrio LoRa Tracker board is based on the RAK Wireless RAK5205 chipset integrating SX1276 LoRaWAN Modem, STM32L151CB MCU and GPS module. Zephyr applications use the 96b_wistrio configuration to run on these boards.

96Boards WisTrio

96Boards WisTrio

This board is one of the 96Boards IoT Edition platform providing LoRa connectivity.


96Boards WisTrio provides the following hardware components:

  • RAK5205 Chipset
  • 3.3V work voltage
  • 128 KB Flash
  • 16 KB SRAM
  • On board sensors:
    • Acclerometer: STMicro LIS3DH
    • Integrated Environmental sensor: Bosch BME680
  • 2 User LEDs
  • GPIO with external interrupt capability
  • UART (2)
  • I2C (1)
  • GPS Module
  • GPS Antenna
  • LoRa Antenna

Supported Features

The Zephyr 96b_wistrio board configuration supports the following hardware features:

Interface Controller Driver/Component
NVIC on-chip nested vector interrupt controller
SYSTICK on-chip system clock
UART on-chip serial port
GPIO on-chip gpio
PINMUX on-chip pinmux
I2C on-chip i2c

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


Connections and IOs


  • LED1 / User1 LED = PA12
  • LED2 / User2 LED = PB4

Push buttons

  • BUTTON = RST (BT1)

Serial Port

96Boards WisTrio board has 2 UARTs. Zephyr console output is assigned to USART1 with 115200 8N1 as the default setting and USART3 is used for GPS module.


96Boards WisTrio board has 1 I2C connected to on-board sensors. The default I2C mapping is:

  • I2C1_SCL : PB8
  • I2C1_SDA : PB9

I2C1 also goes to the J22 connector and can be used to attach external sensors.

Programming and Debugging


Here is an example for building the Hello World application.

# 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=96b_wistrio ..

# Now run ninja on the generated build system:


96Boards WisTrio can be flashed by two methods, one using the ROM bootloader and another using the SWD debug port (which requires additional hardware).

Flashing using the ROM bootloader requires a special activation pattern, which can be triggered by using the BOOT0 pin. The ROM bootloader supports flashing via UART, and I2C but this document describes the UART case only. You can read more about how to enable and use the ROM bootloader by checking the application note AN2606 .

Using ROM bootloader:

  1. Connect 96Boards WisTrio to your Linux PC using, USB-Micro to USB-A cable.
  2. ROM bootloader can be triggered by the following pattern:
    • Connect BOOT0 to VDD (link pin 1 and 2 on J12)
    • Press and release the RST button

More detailed information on activating the ROM bootloader can be found in Chapter 29 of Application note AN2606. The ROM bootloader supports flashing via UART, and I2C protocols.

For flashing, stm32flash command line utility can be used. The following command will flash the zephyr.bin binary to the WisTrio board using UART and starts its execution:

$ stm32flash -w zephyr.bin -v -g 0x08000000 -e 255 /dev/ttyUSB0

Using SWD debugger:

Use the Black Magic Debug Probe as an SWD programmer, which can be connected to the SWD pins exposed on the J22 header using its flying leads and its 20 Pin JTAG Adapter Board Kit. When plugged into your host PC, the Black Magic Debug Probe enumerates as a USB serial device as documented on its Getting started page.

It also uses the GDB binary provided with the Zephyr SDK, arm-zephyr-eabi-gdb. Other GDB binaries, such as the GDB from GCC ARM Embedded, can be used as well.

$ arm-zephyr-eabi-gdb -q zephyr.elf
(gdb) target extended-remote /dev/ttyACM0
Remote debugging using /dev/ttyACM0
(gdb) monitor swdp_scan
Target voltage: 3.3V
Available Targets:
No. Att Driver


After flashing 96Boards WisTrio, it can be debugged using the same GDB instance. To reattach, just follow the same steps above, till “attach 1”. You can then debug as usual with GDB. In particular, type “run” at the GDB prompt to restart the program you’ve flashed.