iMX6: SDMA external Event 0 not working? (Event 1 does)

[Rob_iMX6]

Hi!

I'm working on a iMX6DL board with SDMA and external hardware events. There are two external event lines available: Event 0 on pad T21 and Event 1 on pad U24. (and their alternates)

Event 1 works as it expected:

     1. set IOMUXC_GPR0[7]=1

     2. set IOMUXC_SW_MUX_CTL_PAD_DISP0_DATA17 to ALT4

     3. set IOMUXC_SDMA_EVENTS15_SELECT_INPUT to DISP0_DATA17 (default anyway)

     4. it is mapped to event 14 of the SDMA. Setting CHNENBL14 to the desired channel (channel 1 in my case), i.e. value 2.

     5. and HO=1, EO=0 and CHNPRI1=7

     -> this will let event 1 trigger my SDMA script nicely.

However, the same procedure does not work for the event 0 line. I have verified that the pin is connected (using GPIO) and that the external trigger signal arrives on the chip.

Event 0 is routed to the SDMA by setting IOMUXC_GPR0[0]=1, IOMIXC_SW_MUX_CTL_PAD_DISP0_DATA16=ALT4 and IOMUXC_SDMA_EVENTS14_SELECT_INPUT=DISP0_DATA16

The mapping should be event 2 of the SDMA. I have tried all CHNENBLn, without success.

Furthermore, I have enabled all clocks to be sure (CCM_CCGRn=0xfffffff), without success either.

Any ideas? Looks like a chip bug to me...

Regards,

-Urs

[jial2012]

Hi Rob:

     did you solved your question? I have the same case about how to triggle the external SDMA request pins about IMX6Q SDMA_EXT_EVENT0. if you solved your  problem , please guide something help for me! thanks!

   Best regards

      lingjia

[igorpadykov · Accepted solution]

Hi Rob

yes you are right, attached part of rev.2 i.MX6SDL Ref manual

Best regards

igor

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[Rob_iMX6]

Hi Igor

Thanks for the acknowledgement. Hope that we receive an updated ref manual soon!

Regards,

-Rob aka Urs

[Rob_iMX6]

In the latest iMX6QD Ref manual, there is no SDMA event mapping of the external  hardware event 0 line...

well, might be the same for MX6SDL?