Looking for some advice and help on RFNOC.... I am creating a custom RFNOC block that will roughly do what the noc_block_duc does but instead uses a fractional polyphase interpolator. I believe I have everything working correctly in terms of the tlast and EOB and for single timed bursts it seems to work fine which I can verify on the scope and in chipscope. However when I switch to a streaming data I start getting UUs. If I look at it in chipscope it appears that the incoming data is just not being supplied fast enough. My block is not pushing back. In terms of rates I am using a 1 gig Ethernet connection and am running 32 times interpolation in my block with the radio block being set to 200 MHz. This would imply that I have a 6.25Msps required feed rate to my block. I think this should be well within the 1 gig capability. Again I verified that my block is not pushing back so it really appears the data is not coming down fast enough. My rfnoc graph consists of the radio core connected to my block and then to the host. Nothing else.
I am wondering are there flow control things that I am not doing properly in my block. Perhaps the host UHD code is not getting the right feedback for the flow control? Perhaps sample line rate settings that I should be doing? In my UHD code I am only setting the sample rate in the radio core and it only accepts 200 MHz but does that somehow screw up the flow control? Is there special sauce in the duc that makes it necessary to use that with the radio core to get the rates correct? Thanks for any help. Jeff
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