I observe some strange behaviour. I use DMA for ethernet receive&sending.
After some performance troubles with lost packets on a layer2 protocol i use a timestamp method
to measure the timing of the received frames within the int routine.
i get a minimum time from one frame to the next received frame in the EthDMA Int Routine of 19,6µs
How could this happen ? i send packets for testing with the ostinato burst generator and my packet size is 64Bytes.
if i calc this with interframeGap and preamble etc. there is a min. time from one frame to the next of 6,72µs on a 100MBit line.
But im not able to measure this time and i have lost packets?
i use a fscl of 125MHz and DMA from MAC controller - whats the matter of this timing. how can i accelerate this.
i turned of all other running dma channels with no effect.
I use DMA with flow=7 and to buffers for receiving