I’ve posted my verilog sources. Here is my modified top-level usrp
The PID feedback module is here:
One more accessory module for doing arithmetic is here:
The USRP top level module is, of course, under the GPL. The other 2
I release to the public domain. No warranties, expressed or implied,
In testing, when connecting the control signal output directly into the
controller’s measure input, I was able to achieve settling times of .5
to 1 us.