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K22 SPI DMAs with "Transmit or Receive" Sources

Question asked by lsrbigfoot on Sep 30, 2017
Latest reply on Oct 2, 2017 by Mark Butcher

Typically when setting up TX and RX SPI DMA transfers (on K20 for example), I would use dedicated (or separate) source numbers for TX and RX DMAs. For the K22, I can only use this approach for SPI0 but not for SPI1 and SPI2 because the DMA source numbers on both peripherals appear to be a share resource where I can only do either TX or RX (see below):

 

 

How can I still implement SPI DMAs (TX and RX) on SPI channels with shared DMA source numbers? Any examples?

If not possible, then will I have to set up the transfers such that one transfer is interrupt controlled (likely TX) while the other is DMA controlled (RX)?

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