furnace/doc/7-systems/vic20.md
2023-06-05 00:08:37 -05:00

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# Commodore VIC-20
the Commodore VIC-20 was Commodore's major attempt at making a personal home computer, and is the percursor to the Commodore 64.
it was also known as the VC-20 in Germany, and the VIC-1001 in Japan.
it has 4 voices that have a limited but wide tuning range, and like the SN76489 and T6W28, the last voice is dedicated to playing noise.
the 3 pulse wave channels also have different octaves that they can play notes on:
- the first channel is the bass channel, and it can play notes from octave 1.
- the next is the 'mid/chord' channel, and it plays notes from octave 2.
- and rather obviously, the 3rd pulse channel is typically the lead channel, can play notes from octave 3.
these channels are not referred as "square" wave channels since a technique to play 15 additional pulse-like waveforms has been discovered long after the VIC-20's release.
## effect commands
- `10xx` Switch waveform (`xx` from `00` to `0F`)