[Discuss-gnuradio] two packet transmitters on two daugherboards

[Thomas Schmid]

Hi everyone,

I have a little conceptual problem I don't seem to be able to solve. I
want to have two packet transmitters, one for the daughterboard in
slot A, the other one for the daughterboard in slot B. The two
daughterboards work at different frequencies and use different
protocols, i.e., they have a different interpolation rate etc. I saw
the example on how to use two TX, though this is not possible in that
scenario, because we can not assume that we always have a packet to
send on both channels. Therefore, I tried to use a basic approach that
before you send a message on one board, you reconfigure the USRP. This
doesn't seem to work. My test consisted of first configuring the USRP
for the daughterboard in slot A. Then, I send two messages. These are
sent successful (I can see them on a second USRP on an other
computer). Then, I reconfigure the USRP and send the next two messages
over the daughterboard in slot B. This does not work. The messages are
sent out, though I don't see them on the other USRP! It is to note
that I don't stop the flowgraph before I reconfigure it because the
stop() just blocks and never continues.

Does anybody have an idea on what is going wrong? Do I have to stop
the flowgraph before I reconfigure the USRP? if so, how can i achieve
that stop does not block forever? An suggestions on how to solve that
problem are appreciated.

Thomas