Re: How to use 2 N310 for TX and RX

[Marcus D Leech]

What happens if you just use a single N310 for both TX and RX?

Just trying to figure out where the problem might be. Also please share a 
minimal flow graph that shows the problem. 

Sent from my iPhone

> On Feb 10, 2021, at 1:25 PM, Johannes Demel <demel@ant.uni-bremen.de> wrote:
> 
> Hi all,
> 
> I have a flowgraph where I want to use two N310s for TX and RX.
> 
> If I run `benchmark_rate`, everything works fine.
> 
> ```
> ./benchmark_rate --pps external --ref external --rx_channels "0,4" 
> --tx_channels "2,6" --rx_rate 61.44e6 --tx_rate 61.44e6 
> --args="addr0=192.168.21.218,addr1=192.168.20.213,master_clock_rate=122.88e6
> ```
> 
> It's important that I use one RX and one TX channel each on those USRPs.
> 
> But it seems like I can't do that with
> 
> ```
> [INFO] [UHD] linux; GNU C++ version 9.3.0; Boost_107100; 
> UHD_3.15.0.0-62-g7a3f1516
> [INFO] [MPMD] Initializing 2 device(s) in parallel with args: 
> mgmt_addr0=192.168.20.213,type0=n3xx,product0=n310,serial0=319841B,claimed0=False,mgmt_addr1=192.168.21.218,type1=n3xx,product1=n310,serial1=3180AF3,claimed1=False,addr0=192.168.20.213,addr1=192.168.21.218,master_clock_rate=122.88e6,clock_source=external,time_source=external
> [INFO] [MPM.PeriphManager] init() called with device args 
> `time_source=external,clock_source=external,master_clock_rate=122.88e6,product=n310,mgmt_addr=192.168.20.213'.
> [INFO] [0/Replay_0] Initializing block control (NOC ID: 0x4E91A00000000004)
> [INFO] [MPM.PeriphManager] init() called with device args 
> `time_source=external,product=n310,master_clock_rate=122.88e6,clock_source=external,mgmt_addr=192.168.21.218'.
> 
> [...]
> 
> [INFO] [MULTI_USRP]     1) catch time transition at pps edge
> [INFO] [MULTI_USRP]     2) set times next pps (synchronously)
> [INFO] [MPMD] Initializing 1 device(s) in parallel with args: 
> mgmt_addr=192.168.21.218,type=n3xx,product=n310,serial=3180AF3,claimed=True,addr=192.168.21.218,master_clock_rate=122.88e6,clock_source=external,time_source=external
> [ERROR] [RPC] Someone tried to claim this device again (From: 192.168.21.34)
> [WARNING] [MPM.RPCServer] Someone tried to claim this device again (From: 
> 192.168.21.34)
> Traceback (most recent call last):
>  File "gr-tacmac/examples/usrp_multi_test.py", line 360, in <module>
>    main()
>  File "gr-tacmac/examples/usrp_multi_test.py", line 338, in main
>    tb = top_block_cls()
>  File "gr-tacmac/examples/usrp_multi_test.py", line 133, in __init__
>    self.uhd_usrp_sink_0 = uhd.usrp_sink(
> RuntimeError: RuntimeError: Error during RPC call to `claim'. Error message: 
> Someone tried to claim this device again (From: 192.168.21.34)
> ```
> 
> I can share the example flowgraph. It's just a USRP source connected to a Qt 
> time sink (and a Qt Freq sink). And a USRP sink that's fed by two Signal 
> sources.
> 
> It works if I only have either a USRP sink or USRP source. But in case I try 
> to use both. The configuration breaks with the above error. How do I fix this?
> 
> Cheers
> Johannes
>