My setup is the following: a Nucleo board (Nucleo 144 embedding a STM32H743) is configured as SPI Master. Another identical board is configured as SPI Slave.
For the Master I setup the SPI1 (pins GND, D11, D12 and D13 - PA5,6,7- of the CN7 connector) with following config:
- GPIO: very high speed, alternate function 5
- SPI: prescaler DIV8, interrupts enabled, simplex communication, no Slave Select
- all clocks set to maximum (CPU 400MHz, etc...)
For the Slave I setup the SPI1 too (same pins), it works fine.
Then I tried to switch to SPI2 peripheral for the Slave board and could not make it work (no change to master board). I chose the pins D18 (PB13) for SCK, A7 (PC2) for MISO and A2 (PC3) for MOSI.
I've checked the following points:
- SPI2 periph clock is enabled
- GPIOB and C clocks are enabled and pins PB13, PC2 and PC3 are set up the same way as PA5,6,7 in previous setup.
- for the GND I tried different GND pins on the board, I don't know if it makes a difference.
- the GPIOs used for SPI2 are not used elsewhere in my code. I've got them from the datasheet of STM32H743ZI
What I see:
- my slave is still receiving the SCK signal correctly: I get the correct number of RXP interrupts.
- the data received by the slave is corrupted.
- however the data send by the slave to the master is correct.
I think the MOSI signal is badly configured, either physically or logically. I tried the other GPIO pins whose alternate function can be SPI2_MOSI but same behaviour.
Is there a specificity to SPI2 and/or this GPIO setup ? Does the GND location on the board matter ?
