Media clock generation using eDMA

[sathishkumar_sunmugavel]

Hello Everyone,

I’m working on generating a clock using the GMAC PPS module along with eDMA.

From the documentation, I understand that the mcgr_dma_req_o[3:0] signal gets asserted when the GMAC system time is greater than or equal to the configured target time.

   

sathishkumar_sunmugavel_0-1753271626406.png

sathishkumar_sunmugavel_1-1753271663068.png

My goal is to use this signal to trigger eDMA to automatically update the next target time by copying values into the following registers:

• MAC_PPS0_TARGET_TIME_NANOSECONDS

• MAC_PPS0_TARGET_TIME_SECONDS

I would like to clarify:

• How do I connect mcgr_dma_req_o to the DMA controller? How eDMA will receive Peripheral Request?

• Are these signals internally routed to the DMA MUX in the MCU, or do I need to configure any specific routing?

If anyone has any examples, reference configurations, or application notes for this kind of setup, please share.

The intended behavior is:
Whenever the GMAC system time reaches the current target time, the mcgr_dma_req_o signal triggers a DMA transfer that updates the target time for the next PPS event.

Thanks in Advance!!!