topic Re: Problem using multi channel ADC With DMA in LPC Microcontrollers

Problem using multi channel ADC With DMA

AD11 — Wed, 01 Feb 2023 18:55:30 GMT

Hello,
Currently i've a problem using DMA with ADC.
My use case is: i've 6 ADC Channels, I am triggering adc with a sampling rate and after number of samples requested i want to get all samples in a one go or even after each sample the destination address of each buffer will be incremented internally.

so as an examples, rate is 1 sample per second and number of samples 5, so on first sec, DMA will read from first one then second one till fifth channel and increment each channel destination address by one. next sec it will read from first channel but it'll allocate in the second location of this channel buffer, then second and so on till fifth. and so on.

problem is descriptor never goes to the next one without being exhausted and if i defined number of transactions it will go to second one only after it fills all those transactions.
I successfully used timer to trigger ADC but i couldn't get that done using dma descriptors. i've used single conversion mode and burst mode but both didn't give me this approach.
can you help me with this

Re: Problem using multi channel ADC With DMA

Alice_Yang — Fri, 03 Feb 2023 07:23:30 GMT

Hello @AD11

Please tell us the part number of your chip/board?

Alice

Re: Problem using multi channel ADC With DMA

AD11 — Mon, 06 Feb 2023 21:03:54 GMT

LPC54113

Re: Problem using multi channel ADC With DMA

Alice_Yang — Tue, 07 Feb 2023 02:04:09 GMT

Hello @AD11 ,

Recommend first have a look at the ADC+DMA demo under SDK:

Download from: https://mcuxpresso.nxp.com/en/select

Alice

Re: Problem using multi channel ADC With DMA

AD11 — Thu, 09 Feb 2023 19:00:31 GMT

yes i used this to build my app and it didn't work for me for that approach i posted

Re: Problem using multi channel ADC With DMA

Alice_Yang — Mon, 13 Feb 2023 08:24:50 GMT

Hello @AD11

What about the mainly issue? 6 ADC Channels can work well ? DMA only can read the first channel value?

Alice