[Discuss-gnuradio] issues of synchronizing two USRP N210s

[Pengyu Zhang]

Hi,

I met the following errors when I try to synchronize two USRP N210s. Both N210s are fed with 10MHz reference clock and 1 PPS from an OctoClock. The two N210s are connected via a MIMO cable as well. One N210 is connected to the Ethernet of a MacbookPro (2010 model) via an Ethernet cable. Attached is the flow graph and python program used. When I run the top_block.py, I met the following errors. According to the previous discussion (http://gnuradio.4.n7.nabble.com/Issues-with-syncing-two-USRPs-td48883.html), it seems that this error is caused by Ethernet connection. However, in my setup, the N210 is connected to the MacbookPro via Ethernet directly without router in the middle. So what could be the potential problem?

RuntimeError: fifo ctrl timed out looking for acks

One more information: I am using GNURadio 3.7.7.1 and UHD 3.8.2.

Pengyu

The complete output of running top_block.py is:

$ python top_block.py

linux; GNU C++ version 4.8.2; Boost_105400; UHD_003.008.002-0-ge9d11b35

-- Opening a USRP2/N-Series device...

-- Current recv frame size: 1472 bytes

-- Current send frame size: 1472 bytes

UHD Warning:

    Unable to set the thread priority. Performance may be negatively affected.

    Please see the general application notes in the manual for instructions.

    EnvironmentError: OSError: error in pthread_setschedparam

UHD Warning:

    Unable to set the thread priority. Performance may be negatively affected.

    Please see the general application notes in the manual for instructions.

    EnvironmentError: OSError: error in pthread_setschedparam

--     1) catch time transition at pps edge

--     2) set times next pps (synchronously)

-- Successfully tuned to 915.000000 MHz

--

-- Successfully tuned to 915.000000 MHz

--

-- Opening a USRP2/N-Series device...

-- Current recv frame size: 1472 bytes

-- Current send frame size: 1472 bytes

UHD Warning:

    Unable to set the thread priority. Performance may be negatively affected.

    Please see the general application notes in the manual for instructions.

    EnvironmentError: OSError: error in pthread_setschedparam

--     1) catch time transition at pps edge

--     2) set times next pps (synchronously)

-- Successfully tuned to 915.000000 MHz

--

Using Volk machine: sse4_1_64

thread[thread-per-block[3]: <block gr uhd usrp source (1)>]: RuntimeError: fifo ctrl timed out looking for acks

mimo_signal.grc
Description: Binary data

top_block.py
Description: Text Data