AnsweredAssumed Answered

BF537 ethernet receiving and minimal frames

Question asked by pfeifferc on Sep 6, 2012
Latest reply on Sep 18, 2012 by Stephane

Hi !

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

 

regards chris

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