ADC DMA with TIM21 TRGO conversion source on STM32L010

[DWann]

I've got an application where I'm performing an ADC DMA transfer where the ADC conversions are triggered by the TIM2 TRGO. Everything was running smoothly until a PCB respin forced me to switch over to TIM21 to trigger the conversion. I didn't see a problem with that but now my DMA transfer doesn't work (nothing making it to the buffer).

From the documentation, I see that TIM2 supports DMA request generation while TIM21 does not. Could this be the issue? I wouldn't have thought so - the ADC should be the one requesting the DMA, not the timer. All the timer should be doing is firing the TRGO.

Any thoughts?

[waclawek.jan]

Hi @Amel NASRI​ ,

From this thread, it appears, that TIM21_TRGO is not available for ADC trigger (with EXTSEL=0b100) not only in Cat.1 'L0, but also in Cat.2.

OTOH, there are hints that TIM22_TRGO should be available for ADC trigger, but the 'L0x0 RM does not list it (even if it uses as an example in the Appendix).

Can these issues please be clarified?

Thanks,

Jan

[Amel NASRI]

Hi @Community member​ ,

Thanks for pointing out this issue. I am checking it internally and I will come back to you with details about corrective actions we will take.

As already suggested by you, it will be interesting if you @DWann​  can do the test with TIM22_TRGO.

-Amel

[waclawek.jan]

Thanks, Amel.

Jan