Hi,
We have been working with an (old) USRP1 and doing some modifications in
the
FPGA code. After our modifications (we added an extra layer of DDCs to
perform channel separation in the FPGA), the things didn’t work as
expected.
In some Gnuradio applications the USRP stops sending samples after some
time. For example, usrp_fft.py runs just fine all the time, but
usrp_rx_cfile.py and usrp_wfm_rcv.py work for some secs and then the
USRP
stops sending samples.
I added some pics of our preliminary debugging. In the figures, the
yellow,
blue and red signals refer to the have_pkt_rdy, RD and OE signals,
respectively. After some time, the Cypress stops setting RD and OE
signals
in response to the assertion of have_pkt_rdy (first figure). Latter, the
USB
FIFO in the FPGA overflows and then have_pkt_rdy goes down (figure 2).
So it
seems the problem is not with our modifications in the FPGA code but
with
something related to the Cypress.
Have someone ever had a similar problem ? Any clue in how to solve this
would help a lot. We are using Gnuradio 3.2.2.
The funny thing is that usrp_fft.py works perfectly (we double checked
all
*.py to make sure our new bitstream is always being loadded and our new
DDCs
are being properly configured).
Thanks.
Regards,
Tiago.