EDMA3 completion ISR and PaRAM set reload

Jianzhong Xu

Hi,

I'm using the link feature of EDMA3 and also have a call back function associated with EDMA3 completion ISR - lisrEdma3ComplHandler0. If I call EDMA3_DRV_getPaRAMEntry() inside the call back function, which PaRAM set will be obtained? Another word, which finishes first between lisrEdma3ComplHandler0 and PaRAM set reload?

For example, say PaRAM set 3 is tied to my active EDMA channel and links to PaRAM set 4. When PaRAM set 3 is finished, PaRAM set 4 will be copied to PaRAM set 3. On the other hand, ISR lisrEdma3ComplHandler0 will be running as well. Which gets executed first, ISR or PaRAM set reload? Which PaRAM set will EDMA3_DRV_getPaRAMEntry() inside the call back function read, PaRAM set 3 or PaRAM set 4?

Thanks a lot,

Jianzhong

over 9 years ago

0 Yordan Kovachev over 9 years ago

TI__Guru**** 161600 points

Hi Jianzhong,

I've notified the EDMA expert. Could you elaborate which device is this? Also what software?

Best Regards,
Yordan

0 ran35366 over 9 years ago in reply to Yordan Kovachev

TI__Genius 12805 points

This is very interesting question. I wonder why do you need to know?

Here is what I think. Based on the description in the EDMA User's Guide http://www.ti.com/lit/ug/sprugs5b/sprugs5b.pdf

2.3.7 the link update occurs after the current PaRam parameters have been exhausted (read the text when it happens) So my answer is that completion interrupt ISR will see the new PaRam. The interesting question is what about intermediate transfer completion. (you can see http://processors.wiki.ti.com/index.php/EDMA_FAQ_for_KeystoneI/II_devices#Q._What_type_of_interrupts_does_the_EDMA3_channel_controller_generate_on_transfer_completion.3F

for the conditions for the two interrupts). My guess (only guess) is that the hardware is faster than the ISR response time, so you will see the newer PaRam in the intermediate transfer case as well.

Could you try and run your code and find for sure? I am very much interested in the answer. Please try it and post the results here

Best Regards

Ran

0 Jianzhong Xu over 8 years ago in reply to ran35366

TI__Guru 58785 points

Ran,

Thanks for the information. It makes sense. The reason I wanted to know is for debugging purpose. I'll let you know the results when I try it out.

Regards,
Jianzhong

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EDMA3 completion ISR and PaRAM set reload