This is the upshot of my investigation (I haven’t gotten it working yet) into the imx7 SDMA: It appears really powerful, but very complicated to get started. The imx.6 appears to use the same SDMA engine. The SDMA essentially has its own microprocessor that can be programmed in assembly language. I could not find a compiler for it - but read of someone writing their own. The manual for the sdma is over 200 pages long - I could not find any white paper on how to really use it. I concluded it is just too complicated and no simple examples of how to use as of April or 2017 - so my way to avoid having to use it will be to just have a fast interrupt do what I would have had it do - the A7 is fast enough, it shouldn’t be a problem. The SDMA is a common resource available to any of the 3 processors - I found 2 c files related to a linux use of it, but I think that code was part of a larger set of code I couldn’t find. My guess is only users of million lot quantities who have in house NXP support really have it working - for the rest of us, I recommend use the lightening speed of the A7 to avoid having to learn it
