STM32H743 SPI Topic is solved

[fvantienen]

No I'm not using polled exchange and I checked that if I set it before the spiSelect everything works fine, but if I set it after the spiSelect it doesn't work. I can't actually look at see what happens on the SPI1 bus with an analyser. But I guess that it might either be a timing issue where the register needs to be set quickly after configuring, or it would generate some weird pulses on the bus because it is set after spiSelect.
My guess is that the second one is the problem, in combination with high clock idle state it might generate an 'extra' pulse at the start after spiSelect.

[Giovanni]

Hi,

Update, I am testing on a H755, fixed the problem with polled exchange:

polled_exchance.png (3.67 KiB) Viewed 7920 times

I don't see that clock glitch, at least not in polled mode (my LA is sampling at 200MHz, is yours faster?).

I am not experiencing problems with the existing SPI demo, I am trying to stress the driver some more in DMA mode. Could it be specific to old H743s? which chip revision are you using?

Giovanni

[fvantienen]

I am sampling with 100MSPS so that should not be the problem. I have an STM32H743 with STM32_ENFORCE_H7_REV_XY. Will look into this problem more later, currently switched to V1 where the glitches only occur outside the SS.

Btw I'm not using polled mode at all.

[Giovanni]

Hi,

I verified in DMA mode too (current trunk code), no glitch visible. Could it be a bug on that old H743 revision? Could you try on some other device?

Giovanni