Sega Genesis/Mega Drive

a video game console that showed itself as the first true rival to Nintendo's video game market near-monopoly in the US during the '80's.

this console is powered by two sound chips: the Yamaha YM2612 and a derivative of the SN76489.

effects

10xy: set LFO parameters.
- x toggles the LFO.
- y sets its speed.
11xx: set feedback of channel.
12xx: set operator 1 level.
13xx: set operator 2 level.
14xx: set operator 3 level.
15xx: set operator 4 level.
16xy: set multiplier of operator.
- x is the operator (1-4).
- y is the mutliplier.
17xx: enable PCM channel.
- this only works on channel 6.
- this effect is there for compatibility reasons - it is otherwise recommended to use Sample type instruments (which automatically enable PCM mode when used).
18xx: toggle extended channel 3 mode.
- 0 disables it and 1 enables it.
- only in extended channel 3 chip.
19xx: set attack of all operators.
1Axx: set attack of operator 1.
1Bxx: set attack of operator 2.
1Cxx: set attack of operator 3.
1Dxx: set attack of operator 4.
20xy: set PSG noise mode.
- x controls whether to inherit frequency from PSG channel 3.
  - 0: use one of 3 preset frequencies (C: A-2; C#: A-3; D: A-4).
  - 1: use frequency of PSG channel 3.
- y controls whether to select noise or thin pulse.
  - 0: thin pulse.
  - 1: noise.