STM32WB55 Thread Stack not running on CP2?

YTalh.1 · ‎2021-12-13

I have been using the STM32WB55 Nucleo board successfully to run a CoAP server on OpenThread.

I have designed a custom board which is very similar to the Nucleo board (same microcontroller).

I successfully updated the FUS firmware following the Release Notes documentation (flashed stm32wb5x_FUS_fw.bin at address 0x080EC000, and stm32wb5x_Thread_FTD_fw.bin at address 0x08097000).

When I read the FUS infos, I get:

FUS Status: FUS_NO_ERROR
FUS Version: v1.2.0.0
FUS OPerator: v3.1.0

Now, when I run the program, it looks like function SHCI_C2_THREAD_Init() never returns, as shown in the picture attached:I connected to the UART to get the trace debug output, shown below:

[M4 APPLICATION] **********************************************************

[M4 APPLICATION] WIRELESS COPROCESSOR FW:

[M4 APPLICATION] VERSION ID = 1.13.0

[M4 APPLICATION] FW Type : Thread FTD

[M4 APPLICATION] **********************************************************

The above output tells me that the co-processor FW is correctly flashed.

I not sure where to start here: the microcontroller, crystals, passive components are all the same as the Nucleo board, for which the same exact program runs without issues.

Additionally, the option bytes are the exact same.

Do you have any insight on what could be causing this issue?

YTalh.1 · ‎2021-12-20

Turned out my issue was a hardware one: my external crystal footprint had the wrong pinout, and it looks like CPU2 needs the HSE to start the FW stack, After fixing the crystal, everything worked as expected.