CRC and Byte swapping support not available in i.MX6 ?

[kimbp]

Looking into the datasheet http://cache.freescale.com/files/32bit/doc/data_sheet/IMX6SXIEC.pdf  I get the impression (page 16, table 2) that both CRC and byte swapping are supported by the SDMA unit.

Looking into the reference manual, http://www.nxp.com/docs/en/reference-manual/IMX6SXRM.pdf , there seems to be no hint on how to access these features. Byte-swapping ins mentioned in the feature list of the SDMA though (section 55.1.2).

Any one who can shed some light on this?

[Yuri]

Hello,

  The CRC module was removed in i.MX6 SDMA.

 I think CRC relates to a historical issue. The SDMA (as IP module) was used to

transfer data packages which must have CRC, as Ethernet. This feature is not used

now : some functionality may require CRC as protocol feature (Ethernet, USB).

Our SDMA does not need it.

  Byte-swapping is not used in i.MX6 SDMA scripts.

Have a great day,
Yuri

-----------------------------------------------------------------------------------------------------------------------
Note: If this post answers your question, please click the Correct Answer button. Thank you!
-----------------------------------------------------------------------------------------------------------------------

[kimbp]

I have some SPI communication where both CRC and byte swapping would be convenient.

The SPI slave regards the SPI as a stream of bytes, while the i.MX for efficiency writes out 32bits words. The ECSPI block writes out 32bit in network order, i.e. my internal memory chunk is not streamed in the internally stored order. Would have been nice to have some auto byte swap.

In the slave I can enable CRC8 (bytewise), but in order to benefit from that I now have to run through all my data (burst of 2KB) in network order and make the CRC my self. This is rather expensive from a load point of view.

So don't really agree the SDMA doesn't need it.

I must admit I haven't looked into the details of SDMA scripts. Would it be possible to add the byte-swapping to such script?

[Yuri]

Hello,

  Since, the SDMA is based on the custom RISC core, customers can try design own scripts. 

But we do not provide tools for it.

https://community.nxp.com/message/610351  

Regards,

Yuri.