Hi,
I made a custom board with the STM32WB5MMG module. The custom board contains just the STM32WB5MMG module with pins connected to some of the GPIOs of the module. I tried to interface this custom board with AD5940 potentiostat via SPI in order to get readings. I tested my code with the STM32WB5MMG-DK and the AD5940 board and it is working fine and I am getting the expected readings. But when I try to implement the same code with the custom board, the SPI communication fails. I am using the same pins I use in the DK board (PA1 as SPI1_SCK, PB4 as SPI1_MISO, PA7 as SPI1_MOSI and PA4 as SPI1_CS). I also tried changing the pins but the result is the same. I connected the custom board via USART pin to the computer and I get the following error in the terminal while trying SPI communication.
Just to check if I2C communication also fails, I tried I2C communication with the board and an NFC module (NTAG I2C PLUS) and it is also not working. It cannot read or write via I2C.
I have attached the schematic and pcb of the custom board I am using below:
It is a very simple board and I designed the circuit according to the datasheet. I also don't think it is an issue with the soldering since the USART is working fine (I connect it to computer via a FTDI adapter). I just want some insight on what might be wrong about my custom board. It should not be the code since it works perfectly fine with the DK board.
One thing I should mention is that the BLE also advertises fine for the custom board. Initially it wasn't working but then I found a post in the community where someone suggested upgrading the firmware which fixed the issue with the BLE and it started working fine. The other thing I should mention is that I am not connecting the 100 nF capacitor from PH3_boot pin to VDD. So PH3_boot remains unconnected (which according to the datasheet is grounded internally)
I am just wondering what I am doing wrong with the SPI.
