Here is the sample (intro music)



You can see, it uses only 3 channels, no SFX or sophisticated envelope/shaping.

For the hardware, main MCU is 16F877A @ 20mhz. I want code to run on it, or if it'll be better to have separate chip, I have space for SOIC-8 case, this is why I said 12F683, but it can be say 12F1840 or whatsoever (no space for extra xtal, but I can use CLKOOUT from main chip).