Went to add a Tune button to my BitX40 Raduino but cannot get it to work.
As suggested, added a push button in series with a 1K resistor between pin A1 on connector P1 to ground, as well as a 4K7 resistor between the hot side of C107 at the balance mixer to pin D6 on connector P3, but no carrier output for tuning when button pressed while in transmit.
Rig works fine transmitting ssb.
Looking at my BitX40v3 board (dated 2016) I see that there are no diodes D15 and D16 in place and no balance pot R105 in place. I wonder if I have an upgraded board that has had changes made, and the Tune wire from D6 to C107 needs to attached to another point on the BitX board?
Also D6 remains Low (0v) at all times. Is there some lines in software that needs to be 'Uncommented" or altered to get D6 to toggle between Rx andTx?