i.MX7D SDMA for mem-to-ext peripheral transfers?

[thomasdoerfler]

Hi,

I intend to use the i.MX7D SDMA engine to transfer a byte stream from system memory (DDR RAM) to an FPGA attached to the EIM. The FPGA should be able to trigger transfers using DRQ lines.

I have the SDMA up and running for mem-to-mem transfers (using the ap_2_ap script), but I still have two challenges:

- the SDMA should not increment the destination (FPGA) address from one byte to the next

- each byte should be triggered with the external event (DRQ line)

For i.MX6, there seems to be a ap_2_ap_fixed script, but I don't see it documented for the i.MX7.

Any hints?

[ceggers · Accepted solution]

Hi Thomas,

I have created tools (binutils port + plugin for Lauterbach Trace32) for developing and debugging custom SDMA scripts. It seems that you are already familiar with the basics of the SDMA, so you could easily modify the existing scripts for your need.

Alternatively I can do the necessary customization for you. I should be able to do this within a few days.

Please contact me directly (German preferred )  for more details.

regards
Christian

[thomasdoerfler]

Christian,

this really sounds interesting. Having an adapted script with the required functionality enables the SDMA to fulfill its purpose in my application.

Thanks a lot!

[igorpadykov]

Hi thomasdoerfler

I am afraid such script is not available (not "officially" supported), sorry.

One can try to develop custom script using tutorial : http://billauer.co.il/blog/2011/10/imx-sdma-howto-memory-map/

or with Professional Services: https://contact.nxp.com/new-prof-svcs-sw-tech

Best regards
igor