This program is generates CTCSS tones.
Circuit info: The output is PWM and must be passed though low pass filters (I used 2 RC filters) to create a sine wave, then buffered with an op amp, followed by a 10k trim put to set the final output level.
Suggested filter cut-off frequency is 300Hz
Frequency response can be flattened by adjusting variables in the generateSineWave() procedure.
Copyright 2018 by Dennis Cabell KE8FZX