AnsweredAssumed Answered

K65 DSPI_EDMA driver

Question asked by Tim Robbins on Sep 7, 2016
Latest reply on Sep 22, 2016 by Vincent Göbel

Hello,

I am attempting to use the DMA SPI driver on a K65 with SDK 2.0.

I want to send 40K of data out the SPI to update a LCD screen.

I have successfully done this on a K70 with PE, and also a KL28 with SDK 2.0.

 

The fsl_dspi_edma driver seems to have an upper limit of 512 bytes per transfer as seen here...

 

/* this limits the amount of data we can transfer due to the linked channel.
* The max bytes is 511 if 8-bit/frame or 1022 if 16-bit/frame
*/
if (handle->bitsPerFrame > 8)
{
if (transfer->dataSize > 1022)
{
return kStatus_DSPI_OutOfRange;
}
}
else
{
if (transfer->dataSize > 511)
{
return kStatus_DSPI_OutOfRange;
}
}

 

It is unclear to me why there is a limit. How can I work around this?

 

Thanks.

Tim

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