Does the DMAMUX solve the External DMA Trigger deficiency on STM32 devices?

[Zaher]

I just came across this application note here: Click Here as this still of great interest to me. I just don't know what ST would have to lose if they have added a couple of signals for the DMAC on their future STM32 devices so it can be triggered from external sources. It's been done on legacy devices like the STR91xFA, so why drop that great feature on new series?

As I can see, many people designing products based on the STM32 MCUs/MPUs, and I'm one of them, are suffering because of this deficiency as they had to go through many alternative ways and workarounds to do it somehow. I believe it's still far from the result sought by the ST community.

This DMAMUX thing seems a great idea if this can be utilized to overcome this issue. Still reading through the AN and maybe I've got to get a board with one of those new lines to play with, however, I would love to hear from our experts here on the subject!

Zaher

[Zaher]

** Update **

According to the application note, the Request Generator can be used to generate requests triggered from EXTI line to initiate a transfer from SRAM buffer to a GPIO through the BDMA module.

[TDK]

Can you be a bit more clear about what deficiency you're talking about? The term "deficiency" doesn't appear in the app note.

[Zaher]

I didn't mean the app note itself, but the lack of external DREQ/DACK in the STM32 devices which makes it difficult to trigger DMA from external event. As you can see, I have updated the post with info from the app note to show that the example given might be the solution I'm looking for!

[TDK]

Thanks for explaining. So you want a line that when it goes high (for example) it triggers a DMA request. That does seem useful.

There might also be something where you can use a timer reset line to trigger a timer event which triggers a DMA request. Just guessing.

[Zaher]

Yes, that's exactly what I wanted to do. Supporting that out of the box on one of the STM32 future series would make our life much easier. I'm now addicted to ST and it's whole development ecosystem. I hate to move to other parts just because of this issue. I guess a lot of designers share this with me, as well!

Here is the block diagram of the legacy STR9. It would be great to have this back on a future STM32 device. The DMAMUX seems promising, however, it's not available on all series and I need to test it to find out whether I can achieve the desired result for my application.