Resolved! Currently we make use of three SPI busses on a STM32F405. SPI1 is a slave and SPI 2/3 are masters. I switch SPI1 to master mode and it just doesn't work. I suspect the APB2 bus but I think I have it set correctly.
Here's my code:SPI_HandleTypeDef spi_handle = { .Instance = DEF_SPI_INS_SPI1, .Init = { .Direction = SPI_DIRECTION_2LINES, .BaudRatePrescaler = SPI_BAUDRATEPRESCALER_2, .CLKPh...