1 Reply Latest reply on Feb 21, 2017 1:39 AM by yuval.berger_1799926

    ISO OUT is dropping packets (device is not receiving producer DMA events as expected)

    yuval.berger_1799926

      Using the source-sink isochronous image I came across the following problem:

         

      Senario:

         

      Host sends X bursts (each burst contains 16 packets, packet size = 1024 bytes, mult =1 ), and then queries the cypress fx3 regarding the amount of glDmaPktsReceived (counter of DMA events that is increased when CyFxIsoSrcSinkDmaCallback being called with producer CY_U3P_DMA_CB_PROD_EVENT that occurrs either when the buffer is full or short packet was recieved).

         

      Problem:

         

      glDmaPktsReceived < Total Number of bursts that were sent from the host (verified in sniffer that everything was transmitted). 

         

      NOTE:  working with short packet solves this, for example size of 1023 bytes, test is completed successfully glDmaPktsReceived = Total Bursts sent from the host.

         

      Configuration is:

         

      burst size = 16KB, mult = 1, bInterval=5 (any value between 1..5 has the same issue)

         

      Any ideas? are there any known limitation for FX3 ISO that I should be aware on when working with this device?