topic DMA as double buffer in Kinetis Microcontrollers

DMA as double buffer

wendersonolivei — Mon, 11 Aug 2014 16:29:20 GMT

Hi All,

I'm writing a code to output sound tones on DAC, with DMA. Due to precision that I need on tones, I need to use a dual buffer to process and output data via DMA (ping pong buffer).

Well, I've tried to process data and change the source address at DMA OnComplete event, but I haven't enough time to process all data. In some DMAs, we have a hardware trigger to do ping pong buffer; the DMA present in KL25Z can do that?

Thanks

Re: DMA as double buffer

Hui_Ma — Tue, 12 Aug 2014 06:04:29 GMT

It can use DMA channel link function, such as DMA CH0 as half low buffer and DMA CH1 as half top buffer.

DMA CH0 <=> DMA CH1.

When DMA CH0 finish the transfer link to DMA CH1 for transfer; and when DMA CH1 finish transfer, link to DMA CH0 start.

There need to use DMA continuous mode.

And in each DMA interrupt, the CPU can load new data to each DMA channel related data array.

Wish it helps.
best regards
Ma Hui

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Re: DMA as double buffer

wendersonolivei — Tue, 12 Aug 2014 10:46:07 GMT

Hi Hui,

Thanks for help!

Regards