STM32H745 does not generate SPI clock signal when it is set to 60 Mhz ?

EOzde.1 · ‎2021-09-18

Hello,

I have a 250 Mhz oscilloscope. I am analyzing SPI clock signals at different speeds. Once I tried to have a maximum clock speed for SPIs in H745, I cant see anything from the clock pins. When I set the prescaler to 4(30Mhz) or 8(15Mhz) I can see the clock singal and everything works fine. Does anybody know about this issue ?

Best Regards.

waclawek.jan · ‎2021-09-18

How is the SCK pin's respective GPIO_OSPEEDR field set?

JW

EOzde.1 · ‎2021-09-19

Thanks for the answer.

I tried with different speeds. (low to very high). It does not change anything. BTW I am using SPI with interrupt. Maybe I should use DMA to reach maximum speed ?

waclawek.jan · ‎2021-09-19

Even if the interrupt-based code would be too slow to feed the SPI data continuously, you should see intermittent clocks.

But there may be something in the code which prevents Tx. Try placing a breakpoint at the point where the data register is written.

JW