STM32WB55 Core Board V1.0

Overview

The WeAct Studio STM32WB55 Core Board is a compact multi-protocol wireless and ultra-low-power development board embedding a powerful radio compliant with the Bluetooth® Low Energy (BLE) SIG specification v5.0 and with IEEE 802.15.4-2011.

  • STM32WB55CGU6 microcontroller in UFQFPN48 package

  • 2.4 GHz RF transceiver supporting Bluetooth® specification v5.0 and IEEE 802.15.4-2011 PHY and MAC

  • Dedicated Arm® 32-bit Cortex® M0+ CPU for real-time Radio layer

  • One user LED (Blue)

  • One BOOT button

  • One RESET button

  • USB Type-C connector

  • Onboard 3.3V LDO regulator (ME6231A33M3G)

  • Integrated PCB antenna with 2.4GHz RF filter

  • 32 MHz HSE crystal oscillator

  • 32.768 kHz LSE crystal oscillator for RTC

  • 2.54mm pitch pin headers (P1: 20 pins, P2: 15 pins)

  • 4-pin SWD debug header

Hardware

STM32WB55CGU6 is an ultra-low-power dual core Arm Cortex-M4 MCU 64 MHz, Cortex-M0+ 32MHz with 1 Mbyte of Flash memory, Bluetooth 5, 802.15.4, USB, AES-256 SoC and provides the following hardware capabilities:

  • Ultra-low-power with FlexPowerControl (down to 600 nA Standby mode with RTC and 32KB RAM)

  • Core: ARM® 32-bit Cortex®-M4 CPU with FPU, frequency up to 64 MHz

  • Radio:

    • 2.4GHz

    • RF transceiver supporting Bluetooth® 5 specification, IEEE 802.15.4-2011 PHY and MAC, supporting Thread and ZigBee® 3.0

    • RX Sensitivity: -96 dBm (Bluetooth® Low Energy at 1 Mbps), -100 dBm (802.15.4)

    • Programmable output power up to +6 dBm with 1 dB steps

    • Integrated balun to reduce BOM

    • Support for 2 Mbps

    • Dedicated Arm® 32-bit Cortex® M0+ CPU for real-time Radio layer

    • Accurate RSSI to enable power control

  • Clock Sources:

    • 32 MHz crystal oscillator with integrated trimming capacitors (Radio and CPU clock)

    • 32 kHz crystal oscillator for RTC (LSE)

    • Internal low-power 32 kHz RC

    • Internal multispeed 100 kHz to 48 MHz oscillator, auto-trimmed by LSE

    • 2 PLLs for system clock, USB, and ADC

  • RTC with HW calendar, alarms and calibration

  • Up to 24 capacitive sensing channels

  • 16x timers:

    • 2x 16-bit advanced motor-control

    • 2x 32-bit and 5x 16-bit general purpose

    • 2x 16-bit basic

    • 2x low-power 16-bit timers (available in Stop mode)

    • 2x watchdogs

    • SysTick timer

  • Memories

    • 1 MB Flash, 2 banks read-while-write

    • Up to 256 KB of SRAM

  • Rich analog peripherals

    • 12-bit ADC 4.26 Msps, up to 16-bit with hardware oversampling

    • 2x ultra-low-power comparator

SMBus/PMBus)

  • 1x USB 2.0 FS device, crystal-less, BCD and LPM

  • Security and ID

    • 3x hardware encryption AES maximum 256-bit

    • HW public key authority (PKA)

    • True random number generator (RNG)

    • 96-bit unique ID

More information about STM32WB55CG can be found here:

Supported Features

The weact_stm32wb55_core board supports the hardware features listed below.

on-chip / on-board
Feature integrated in the SoC / present on the board.
2 / 2
Number of instances that are enabled / disabled.
Click on the label to see the first instance of this feature in the board/SoC DTS files.
vnd,foo
Compatible string for the Devicetree binding matching the feature.
Click on the link to view the binding documentation.

Bluetooth and STM32WB Copro Wireless Binaries

IMPORTANT: The WeAct STM32WB55 Core Board ships with a “Full Stack” wireless binary pre-installed on the Cortex-M0+ coprocessor. This binary is NOT compatible with Zephyr and must be replaced with an “HCI Layer” binary before using Bluetooth functionality.

To operate Bluetooth on the WeAct STM32WB55 Core Board, the Cortex-M0+ core must be flashed with a valid STM32WB Coprocessor HCI binary. These binaries are delivered in STM32WB Cube packages, under Projects/STM32WB_Copro_Wireless_Binaries/STM32WB5x/

For this board, the extended HCI binary has been tested: stm32wb5x_BLE_HCILayer_extended_fw.bin

For compatibility information with the various versions of these binaries, please check hal_stm32:lib/stm32wb/README.rst.

Flashing the Wireless Coprocessor Binary

The Cortex-M0+ wireless coprocessor binary requires an external debug probe and STM32CubeProgrammer to flash. DFU mode cannot be used for the M0+ coprocessor. Connect an external debug probe (ST-LINK/V2 or J-Link) to the 4-pin SWD header (P3) and use STM32CubeProgrammer to program the binary at the appropriate memory address.

The install address for STM32WB5xxG (1M variant) varies by binary type (v1.23.0):

  • BLE_HCILayer_extended: 0x080DB000

  • BLE_HCILayer: 0x080E1000

FUS (Firmware Upgrade Services) install address (v2.1.0):

  • FUS v2.1.0: 0x080EE000

See the STM32 Wireless Coprocessor Binary Table for complete address information.

Connections and IOs

Default Zephyr Peripheral Mapping:

  • UART_1 TX/RX : PA9/PA10

  • LPUART_1 TX/RX : PA2/PA3 (with CTS: PA6, RTS: PB1)

  • I2C_1_SCL : PB8

  • I2C_1_SDA : PB9

  • SPI_1_NSS : PA4

  • SPI_1_SCK : PA5

  • SPI_1_MISO : PB4

  • SPI_1_MOSI : PB5

  • PWM_1_CH1 : PA8

  • PWM_2_CH1 : PA15

  • ADC_1_IN5 : PA0

  • ADC_1_IN6 : PA1

  • USER_LED (Blue) : PB2

  • BOOT_BUTTON : PE4

  • USB_DP : PA12

  • USB_DM : PA11

System Clock

The WeAct STM32WB55 Core Board system clock is driven by a 32 MHz HSE crystal oscillator. By default, the system clock is configured to run at 64 MHz using the PLL with HSE as the source.

Power Supply

The board includes an ME6231A33M3G 3.3V LDO regulator that accepts input voltage from 3.3V to 5.5V. Power can be supplied via:

  • USB Type-C connector (5V)

  • VDD5V pins on header P1

  • VDD33 pins on header P2 (3.3V regulated supply)

Serial Port

The board has 1 USART and 1 LPUART. The Zephyr console output is assigned to USART1 (PA9/PA10). Default settings are 115200 8N1.

Programming and Debugging

The weact_stm32wb55_core board supports the runners and associated west commands listed below.

flash debug

The WeAct STM32WB55 Core Board does not include an onboard debugger. The Cortex-M4 can be flashed via DFU mode without an external probe, however the Cortex-M0+ coprocessor requires an external debug probe (ST-LINK/V2 or J-Link) connected to the 4-pin SWD header (P3).

Flashing

Installing dfu-util

It is recommended to use at least v0.8 of dfu-util. The package available in debian/ubuntu can be quite old, so you might have to build dfu-util from source. There is also a Windows version which works, but you may have to install the right USB drivers with a tool like Zadig.

Flashing an Application

Connect a USB Type-C cable and the board should power ON. Force the board into DFU mode by keeping the BOOT button pressed while pressing and releasing the RESET button.

The dfu-util runner is supported on this board and so a sample can be built and tested easily.

# From the root of the zephyr repository
west build -b weact_stm32wb55_core samples/basic/blinky
west flash

# From the root of the zephyr repository
west build -b weact_stm32wb55_core samples/hello_world
west flash

Alternatively, if you have an external debug probe (ST-LINK/V2 or J-Link) connected to the SWD header (P3), STM32CubeProgrammer can also be used to flash the Cortex-M4 application using the --runner (or -r) option:

$ west flash --runner stm32cubeprogrammer

Debugging

You need an external debugger connected to the SWD header (P3) to debug applications on this board. You can then debug an application in the usual way. Here is an example for the Blinky application.

# From the root of the zephyr repository
west build -b weact_stm32wb55_core samples/basic/blinky
west debug