Thanks for the ideas.
99.99x99.99 for board size.
I was thinking maybe the Arduino Nano 2560 Mini Pro, About $13... lots of IO...
But then, with the nano, when using I2C, there are 6 extra IO ports. Its just program memory...
I did want to limit FW changes, I was hoping to only have to change the code relating to LPF and BPF...
I'm thinking 5 LPFs and BPF that are switched in. Builder selects the 5 bands they want to operate on and builds the radio/software for that...
The more I think this over the bigger it becomes.
Farhan has achieved so much already! I would only do stuff if he was OK with it,