[Discuss-gnuradio] reading two rx channels on usrp2

[Tom Gross]

I am in the process of hacking up the usrp2 host and firmware to
support two receiver channels.  I'm at the point where
"start_rx_streaming" is being acknowledged for channel 1 but there is
no data being returned for that channel.  I don't actually understand
yet where the receiver data is packaged to be sent over the ethernet
(I haven't really looked into that yet) but I have been trying to
understand how which receiver channel is selected...

I'm guessing that the bits in rx_mux in dsp_rx_regs_t are used to
connect one of two DACs to one (or two?) inputs of the digital down
converter.  I note that the current setting of rx_mux is  0x44444444
which I am guessing (based on the comments in memory_map.h) could mean
"constant 0" for one input and "DAC A" for the other input to the
DDC...  Am I interpreting that correctly?  Can anyone give me some
hints as to what the setting would be if I want to enable both
channels?  Any other insights as to how to access both channels in the
USRP2 firmware?

-Tom