# Problem Collection for USRP
+ If gnuradio unfound the rfnoc module, that may due to incorrect programming of .v file.

+ [WARNING] [X300] For the 192.168.10.2 connection, UHD recommends a receive frame size of at least 8000 for best performance, but your configuration will only allow 1472.
The link rate for GigE is 1427, while it's 8000 for 10GigE.
https://files.ettus.com/manual/page_transport.html

+ [ERR] 1 Unresolved connection(s)
+ Check icore.yml. There's must be port connected incorrect.

+ No attribute
+ lib problem from python. Make sure the yml file for gnu radio is correct and do make ldconfig after install.

+ runtimeerror: cannot find block!
+ Noc_ID in add_block_ctrl_impl.cpp wrong.

+ One or more blocks timed out during flush! UHD recv() call timed out.
+ tlast in .v may be connected incorrectly.

+ Test bench may be fail while vivado gui is run, especially HLS stage. This problem is due to HLS is called by vivado gui.

+ ERROR: [Chipscope 16-213] The debug port 'u_ila_0/probe0' has 16 unconnected channels (bits). This will cause errors during implementation.
+ Go to the directory where the xdc file at and use the following command to update back to the original one.

    git checkout x300_dram.xdc

+ Alternatively way is using vivado gui to remove them.

+

    RuntimeError: 
    GR-UHD detected ABI compatibility mismatch with UHD library.
    GR-UHD was build against ABI: 4.0.0,
    but UHD library reports ABI: 4.1.0
    Suggestion: install an ABI compatible version of UHD,
    or rebuild GR-UHD component against this ABI version.

+ Build and install GNU Radio again

+ If GnuRadio can't enable RX port properly. The LED indicator didn't flash.
+ try ```uhd_fft -f 915e6 -s 10e6 -g 10``` to make sure whethere it's due to GnuRadio or UHD.

+ Sample rate too high
+ It'll result CPP buffer overrun and GnuRadio freeze. Changing connectiong to PCIe will solve the problem.

###### tags: `USRP`, `FPGA`, `Ettus Research`, `UHD`, `RFNoC`, `RFNoC搭建`, `Multiple I/O RFNoC`, `RFNoC Vivado`