I'm working on another software mod that was inspired by the IC22S version that has adjustable CTCSS tones.
Here is a version on progress that has 40 channels and the CTCSS tones are adjustable as are the channel frequencies. So far, the simplex/duplex is still fixed and there is no test to limit out of band when the duplex offset is applied. Also, it would be nice to store the frequencies for later use. I'll need help with that as I have never used that option.
This code uses A3 to select the mode. >200 = set frequ. >400 = set CTCSS. Something else can be added at >550.
Please feel free to have a play.
For some ADC resistors..
Pull down = 10K
buttons with resistors switched to +5V..
22K reads about 320.
10K reads about 512.
6K8 reads about 609.
Both 22K and 10K together = close to 6K6, so that will give you 4 states with 2 buttons, including 0V.
EDIT: Updated code at 17:25 20230315 and some resistors?