I am trying to transfer data over SPI3 on HS at 20Mbps rate. I am testing the speed by writing and reading 1MB of data at 32K bursts. SPI transfer rate I am seeing is about 7Mbps. Each 32K burst takes about 37ms to transfer. I connected Saleae SPI analyzer and captured the transfers. What I am seeing is, during the 32K burst transfer, there is time gap of about 2 micro secs between each byte transferred. I can’t explain where this time gap is coming from. I bumped up the SPI master’s thread priority to real-time and still it didn’t make any difference. Is this wait time coming from SSP pl022? Is there any special settings/mode for higher SPI speed? If anyone has tried SPI at higher speed, please comment.
I appreciate any suggestions.