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# 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.
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this console is powered by two sound chips: the [Yamaha YM2612 ](ym2612.md ) and [a derivative of the SN76489 ](sms.md ).
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# 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).
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- `y` is the multiplier.
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- `17xx` : enable PCM channel.
- this only works on channel 6.
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- **this effect is there for compatibility reasons** - it is otherwise recommended to use Sample type instruments (which automatically enable PCM mode when used).
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- `18xx` : toggle extended channel 3 mode.
- 0 disables it and 1 enables it.
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- only in extended channel 3 chip.
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- `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.
