AnsweredAssumed Answered

DMA transfer (Reception) not proper when implemented with ethernet communication

Question asked by mishra.arun on Nov 24, 2014
Latest reply on Nov 24, 2014 by waclawek.jan
Hello there,

I am using Lwip library for Ethernet implementation. I poll for the Ethernet packet in main loop. Then the packet is passed to further libraries to process it. 
Meanwhile I have also to receive 8 bit data on Port GPIOH  with clock on Timer 8 capture. Using DMA2, channel 7. 
Receiving 220 bytes of parallel  data @20 Mhz. DMA transfers it from GPIO port H to internal RAM


If I run the DMA without ethernet, it runs perfectly fine. but when ethernet is switched on, some of the DMA packets are lost.
Did a test and found 400 packets out of 100000. (0.4%)


Do not have sufficient window to retransmit the packet. 
But cannot afford to loose the packet.
Hardware issues like noise etc are ruled out. Please Help.


Thanks in advance

Outcomes