STM 32F4xx - limitations on a DMA controller configuring another DMA controller

[peter-h]

There are some bus limitations, mentioned here in a recent thread. But in general, is this supposed to work?

I have a feeling one could do quite clever stuff with that.

[wek]

> There are some bus limitations

Yes, and you can use only DMA2 to DMA into DMA.

> But in general, is this supposed to work?

Yes, why not.

> I have a feeling one could do quite clever stuff with that.

Hardly so.

Among other things to start a transfer you need to write at least to two discontinuous registers (clear the TC flag and set the enable bit), and for anything even marginally useful also to the memory pointer register, and maybe also the count (NDTR) register. That is, you'd need 2-4 other DMA streams to serve this one. Probably doable, but doesn't sound to be useful.

Newer STM32 ('H5 for example) have a much more sophisticated DMA.

JW