Hi,
I currently have edma set up in ping pong transfer mode that is delaying a hwi. I am seeing a large ringing latency. Below is a graph of the period of my hwi that is being triggered at 1600Hz. This is a c6748 running at 372MHz. As seen in the graph, there is a periodic ringing where nearly 3000 ticks or 16us of latency spikes and then decays over about a hundred cycles of interrupts. I have isolated the culprit of this ringing to edma ping pong transfer.
I stumbled upon a different thread: http://e2e.ti.com/support/embedded/bios/f/355/t/91872.aspx?pi199400=2 that talks about a similar issue, but he was using it in polling mode. This ping pong uses callback functions instead, so I am not sure if this was relevant to my situation.
EDIT 1: Is there someway to have my HWI always interrupt the edmas? Also, I'm finding that another cause of occasional latencies (around 30-40 us) is caused by my app's spi driver. That driver is in IOM_INOUT mode and using edma as well.
SYSBIOS 6_34_04_22
EDMA3 2_11_06_01
BIOSPSP 03_001_01_00
TI C6748
