[Discuss-gnuradio] Reading registers on the USRP

[kevinmbo]

Hi,

I'm having a little trouble reading the readback registers that are on the
USRP.  I know that most registers are write only with their contents
mirrored on the computer.  The reason I want read those registers back is
because of a custom unit I am testing.  I currently load a custom
implementation on the USRP that consists of 1 TX chain and 2 custom units,
one of which feeds back information into the unused readback ports (rssi0
to rssi3). I'm able to read from the capabilities register using
'_read_fpga_register(FR_RB_CAPS)' and it returns a value that makes sense.
 When I try reading from any other register, the value returned is
consistently '0'.  I'm reading the registers in a loop in case the value
changes after a given amount of time.  I'm not sure what to try next, can
someone give me a new direction?

-Kevin