This is simple simcovox for people, who do not like to modify their precious Atari computer.

By using microcontroller, I was able to reach highest 8-bit quality of sound, as we all know, that Atari8-bit ports are armed with 220 ohm, 1nF capacitors and 10uH solenoids, which makes digital signals not fully digital for some time. The ordinary attempt - using R-2R ladder caused spikes on bit flipping and in general spikes everywhere for 1/4/1/5 of one sample time of freq 15600 Hz. Atmega code filters that out and plays smoothly.

The 8-bit PWM method used in Atmega plays samples with 62.5 khz base frequency, so it is not hearable at all even for your pets.

The code for Atmega328p was adopted from another project, so some settings are unneccessary.

The best working version of Arduino is that with 16MHz and 3.3V stabilizer to cut off digital noise from computer.

I do not want to spend more time cleaning up the code, it works as it is.