DMA limitation for STM32L0 accessing GPIO

Asked Oct 23 '19 at 12:54

Active Oct 23 '19 at 15:14

Viewed 353 times

I am using a STM32L072KB microcontroller and tried to get familiar with timers. I wanted to use a timer to toggle a GPIO/LED via DMA. I read on a book "Mastering STM32" (https://leanpub.com/mastering-stm32) that it is obviously not possible here, to use DMA for directly accessing the GPIO with a STM32L0 core, but I have not found anything in the reference manual which confirms that restriction (https://www.st.com/resource/en/reference_manual/dm00108281.pdf):

Here is the example of the book for a F4-core which uses the timer+DMA and access the GPIO directly:

https://github.com/cnoviello/mastering-stm32/blob/master/nucleo-f401RE/src/ch11/main-ex2.c

But it seems to be true: I found on a forum a post, that someone supposes that for the L0-core a PWM can be used additionally as a workaround to get work with DMA.

Can someone please explain me, why DMA cannot access GPIO directly on a L0-core and how I can implement a GPIO/LED toggle (perhaps with the PWM proposal)?

edited Oct 23 '19 at 15:14

asked Oct 23 '19 at 12:54

user9564464

I would suggest to find a TRM for this type of SoCs and read it, though I suspect the best answer is inside some non-public documentation.. – 0andriy Oct 24 '19 at 07:38
@0andriy that's what the OP did : " but I have not found anything in the reference manual which confirms that restriction" – Guillaume Petitjean Oct 24 '19 at 09:58
@GuillaumePetitjean, and see what I wrote afterwards. – 0andriy Oct 24 '19 at 11:01

DMA limitation for STM32L0 accessing GPIO

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