Restart SPI DMA Transmit without Reconfiguration

ygtcbs — Thu, 10 Nov 2022 18:16:30 GMT

Hi, I'm developing a project with S32K116 and using NXP SDK version 4.0.1.

I want to send 16 bit data with FLEXIO SPI. But with the FLEXIO_SPI_DRV_MasterTransfer function it takes a very long time. The function takes around 20-30us in polling and interrupt mode(I'm using 48MHz HIRC).

But in the project, I need to do this as soon as possible. That's why I decided to use DMA. But the FLEXIO_SPI_DRV_MasterTransfer function takes 150us in DMA Mode. because it reconfigures DMA in every call. I moved the configuration to a separate function (includes EDMA_DRV_ConfigMultiBlockTransfer functions). I call EDMA_DRV_StartChannel and FLEXIO_SetShifterDMARequest to start communication in the loop, and call EDMA_DRV_StopChannel and FLEXIO_SetShifterDMARequest functions in FLEXIO_SPI_DRV_MasterEndDmaTransfer to stop communication. I don't disable or clear FLEXIO Shifters (do I need to?).

But I could not communicate in this way. Do you have a suggestion to shorten the transmit time? Or can you share a documentation or sample code link just for my use case of DMA?

Re: Restart SPI DMA Transmit without Reconfiguration

VaneB — Tue, 29 Nov 2022 18:19:41 GMT

Hi @ygtcbs

A truly apology for the late response.
There are some examples related to the DMA, SPI and FLEXIO included in the S32K1xx SDK RTM v4.0.1.

...\nxp\S32_SDK_S32K1xx_RTM_4.0.1\examples\S32K116\driver_examples\communication

The example documentation can be found in the S32 SDK documentation at Examples and Demos section.

...\nxp\S32_SDK_S32K1xx_RTM_4.0.1\doc\Start_Here.html

B.R.

VaneB

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Restart SPI DMA Transmit without Reconfiguration

Re: Restart SPI DMA Transmit without Reconfiguration