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scanning all ADC channels within DMA

Question asked by Arnold Bischof on Apr 29, 2014
Latest reply on Jan 15, 2017 by Mark Butcher

I have designed a software driver which scans all AD channels of a MK10DN within DMA.

This device has some A channels and some B channels (e.g. ADC0.SE4a and ADC0.SE4b).

In my approach I use the PDB which cyclically triggers both AD channels A at 0 and B at half cycle time using the hardware trigger mode. Additionally I use one linked DMA channel which programs the channel selection into SC1A and SC1B alternately. For the transfer of the converted AD values, I use a second DMA channel which copies the RA and RB registers alternately into a table in RAM. The second DMA is triggered by ADC conversion complete.

 

This approach works fine for AD channels without suffix A and B (e.g. ADC0.SE8 and ADC0.SE9) but the A/B channel pairs (e.g. ADC0.SE4a and ADC0.SE4b) do not work proper. I see the same converted value in the values table for the A and B channel whereas the voltages on a and b are different.

 

I need some help to get the A and B channels within DMA

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