OMAP-L138: What value do I have to set a EDMA PaRAM ACNT when I use McASP AFIFO?

j-breeze

Part Number: OMAP-L138

Hi Champs,

Do I have to set the ACNT to be equal to or greater than McASP WFIFOCTL.WNUMEVT when I enable the AFIFO?
What will happen if I set the ACNT to be less than the WNUMEVT?

I'd like to make sure of it.

Regards,
j-breeze

over 7 years ago

0 Yordan Kovachev over 7 years ago

TI__Guru**** 161600 points

Do you have any OS in mind? If yes, which SDK version?

The sw team is notified of this and will post their feedback directly here.

Best Regards,
Yordan

0 j-breeze over 7 years ago in reply to Yordan Kovachev

Mastermind 7560 points

Hi Yordan,

I use SYS/BIOS v6.46.5.55. But I don't think that the setting value is depend on any OS.

Regards,
j-breeze

0 j-breeze over 7 years ago in reply to j-breeze

Mastermind 7560 points

Hi,

Could you please let me know if you have any updates on this matter?

What value do I have to set a DMA transfer size and McASP WFIFOCTL.WNUMEVT when I use 2 serializers and 8-slot each w/ McASP AFIFO?

Best regards,
j-breeze

0 Garrett Ding over 7 years ago in reply to j-breeze

TI__Mastermind 43296 points

Hi J-breeze,

Sahin has been looking into the questions, but he is out of office this week, will reply you after he is back.

Regards,
Garrett

0 Sahin Okur over 7 years ago in reply to j-breeze

TI__Mastermind 27355 points

Hi j-breeze,

WNUMEVT can be set to an integer multiple of WNUMDMA (number of serializers) depending on how much delay you want, see the following:

If you change WNUMEVT to be more than WNUMDMA, then you need to make sure that ACNT x BCNT are equal to the number of bytes/words expected every trigger event. This is explained by Mukul in more detail in the following thread.

0 j-breeze over 7 years ago in reply to Sahin Okur

Mastermind 7560 points

Hi Sahin and Garrett,

I appreciated your support.
I will follow the settings of the Throughput Presentation in the TI wiki page.

Regards,
j-breeze

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OMAP-L138: What value do I have to set a EDMA PaRAM ACNT when I use McASP AFIFO?