SPIM transfer from RTC handler gets stuck

RE: SPIM transfer from RTC handler gets stuck

NewtoM — Fri, 07 Oct 2016 07:06:00 GMT

Hi RK and thanks for the answer. The above was just a simplified description of what happens. Of course I am not really waiting, but at a specific point I was asserting the SPIM transfer having finished. And in the said case it never have.

Apart from this, your answer is correct. It had to do with the IRQ priorities. When increasing the SPI handler's priority, everything works as expected.

Thank you!

RE: SPIM transfer from RTC handler gets stuck

RK — Fri, 07 Oct 2016 01:20:18 GMT

"waiting for the SPIM handler to signal end of transfer", do you mean that, are you actually sitting in the code spinning around waiting for a flag to show the end of the transfer?

Because if you are doing that in an interrupt handler, you're not returning from the interrupt handler and most likely the SPI handler is of equal or lesser priority than the RTC one so it never gets to run. And if you're blocking in the RTC handler, that's pretty much the wrong thing to be doing anywa.

RE: SPIM transfer from RTC handler gets stuck

NewtoM — Thu, 06 Oct 2016 12:40:14 GMT

Thanks for the quick reply, Sigurd! My revision is QFAAB0 so that should not be the problem. RTC2 seems to function (toggling an LED from its handler works).

RE: SPIM transfer from RTC handler gets stuck

Sigurd — Thu, 06 Oct 2016 12:37:27 GMT

What IC revision is this? It might be this problem.