Hi, RFNoC has flow control built in. By design, the host will not transmit a packet to your RFNoC block unless it can accept that packet. The flow control mechanism happens behind the scenes, there is nothing special you need to do.
Jonathon On Tue, Aug 15, 2017 at 11:45 AM, James Dunn via USRP-users < usrp-users@lists.ettus.com> wrote: > Hello, > > We have been using RFNoC to implement a complete radio system (PHY + MAC) > on the FPGA with limited control and interfacing in GNURadio. Because the > MAC can exhibit arbitrary transmit delay, we need some method to prevent > the host from sending packets when the transmit buffer on the FPGA is > full. We planned on implementing a split SW/HW buffer to handle this > issue. However, to make this scheme work, we need some flow control > mechanism to prevent the host from emptying its buffer when there is no > room in the FPGA buffer. We have done some Googling and came across > references to a flow control mechanism built into CHDR and RFNoC ( > https://static1.squarespace.com/static/543ae9afe4b0c3b808d7 > 2acd/t/55f85bc2e4b067b8c2af4eaf/1442339778410/3-pendlum_jona > thon-rfnoc_tutorial_fpga.pdf, http://ionconcepts.com/files/U > SRP3_concepts.pdf). However, we are not sure if this flow control > mechanism exists only within the FPGA context or if it extends to > UHD/GNURadio on the host. We could also not find an example of this form > of host to FPGA flow control. Can anyone point us to some flow control > examples or documentation? Thanks! > > James Dunn & Chris Yarp > > _______________________________________________ > USRP-users mailing list > USRP-users@lists.ettus.com > http://lists.ettus.com/mailman/listinfo/usrp-users_lists.ettus.com > >
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