Sending extra info (rssi) in ethernet frames from USRP2 to host

Hi, *

I am reading through the firmware C codes and trying to figure out how
to
carry the RSSI values from auxiliary ADC in the word0 section of each
ethernet frame. I was confused by the structure of the firmware C codes.
In
the main() of txrx.c, there is no explicit function calls looks like
send(),
recv() for handing the ethernet frames. And I found in
mimo_app_common_v2.c
some functions like send_reply(), set_reply_hdr() and
handle_control_chan_frame() which may correspond to this issue.
I also tried to modify the u2p_set_word0() function in
usrp2_eth_packet.h in
order to carry the RSSI value. But it seems that this only works when
starting streaming as every frame rceived on the host side shows the
same
value.
I really want to know how does the frameware handle the samples and
controlling frames. Any hints?

Thanks in advance.
Hanwen

Forget to mention, we are using GR 3.2.2, not the newer one with UDP
supported.

Cheers,
Hanwen

2010/4/21 hanwen [email protected]