I have troubles using SPI3 on STM32U575VG. After some time the transfer hangs and it is not possible to amend it until whole reset.
Configuration: Only transmit, is feeds LCD display, 240 lines, 54 bytes each.
APB3 clock 48 MHz. Manual CS handling, SCLK 1.5 MHz.
Everything looks ok, it works, but after some time and on some boards only it hangs. The problem appeared in the start of production.
Symptoms: after configuration and LL_SPI_Enable(), the DMA transfers 16 bytes to the FIFO. That's ok, DMA works. But after LL_SPI_StartMasterTransfer(), the transfer doesn't start.
Looking at the pins, SCLK remains low and MOSI contains some data, but very slow, one bit interval seems to be 8 ms.
Reset of the SPI doesn't help. Reinit of the whole MCU after STOP2 (without reset), including all clocks doesn't help. The only thing that works is the reset of the whole MCU.
I have no idea where to look at more. The SPI is not overclocked, it doesn't wait for any external signal. It happens sometimes after a few minutes, sometimes after hours.
