Possible SPI master bug when using DMA

RE: Possible SPI master bug when using DMA

codezork — Mon, 15 May 2017 19:27:32 GMT

Thank you. I had the same problem with the endless loop. Sad that there are no examples for the advanced use cases in the SDK so somebody could discover issues with that. It is still present in the version 13.

RE: Possible SPI master bug when using DMA

Ole Bauck — Tue, 21 Feb 2017 15:52:30 GMT

Ok, I did not realize that you where using the list feature (the NRF_DRV_SPI_FLAG_TX_POSTINC flag will enable this). Then I understand your problem.

I will report this internally

RE: Possible SPI master bug when using DMA

Braver — Tue, 21 Feb 2017 14:10:23 GMT

It was my understanding that the NRF_DRV_SPI_FLAG_HOLD_XFER flag can be used in combination with PPI. We would program the spi peripheral with the right parameters and then generate repeated start events using a timer. A counter would then count the spi start events and notify the CPU when the data has run out and needs to be refreshed, again calling the spi_xfer function. A spi event handler in this situation would just invoke unnecessary interrupts.

RE: Possible SPI master bug when using DMA

Ole Bauck — Mon, 20 Feb 2017 12:24:28 GMT

I agree that this can happen, but I don't see when you need to use the NRF_DRV_SPI_FLAG_HOLD_XFER flag if you don't have an event handler. You will need to know in the application when the transfer is finished, so if you don't have an event handler you will have to add the while loop in main after you trigger the start task.