IMX6 Linux SPI Slave mode - data read is incomplete/incorrect

[Yavuz]

Hi Everybody, 

I have set IMX6 to run Linux Kernel 5.4.24 for spi in slave mode transfer. 

When Run the command:

spidev_test -v -b  32 -H -D /dev/spidev2.0 -s 15000000

I modified the spidev_test to transmit 256 bytes as default buffer,

The received buffer displayed is correct for first 4 bytes, then deformed for next 8 bytes and remaining (256 - 24) 232 bytes are in correct. 

The remote SPI master is transmitting 256 bytes. but I can only read 4 correct 8 deformed and rest incorrect. 

I have seen some explanations on burst size setting, but I did not understand where and how to set this BURST_LENGTH parameter. 

Best Regards

Y. 

[igorpadykov]

Hi Yavuz

this issue may be related to signal integrity (noise) and one can try to tweak

pad drive strength (DSE) described in AN5078

Influence of Pin Setting on System Function and Performance

and pay attention to cables.

Best regards
igor

[Yavuz]

Hi. 

@igorpadykov  thank you for your response, after detailed investigation it seems that the incoming data was correct and spi slave mode read was successful. 

regards

Y.