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101
papers/doc/7-systems/ym2203.md Normal file
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# Yamaha YM2203 (OPN)
a cost-reduced version of the YM2151 (OPM).
it only has 3 FM channels instead of 8 and removes the LFO.
however it does contain an AY/SSG part which provides 3 channels of square wave with noise and envelope.
this chip was used in the PC-88/PC-98 series of computers, and in some arcade boards.
several variants of this chip were released as well, with more features.
# effects
- `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.
- `18xx`: toggle extended channel 3 mode.
- 0 disables it and 1 enables it.
- only in extended channel 3 system.
- `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.
- `20xx`: set SSG channel mode. `xx` may be one of the following:
- `00`: square
- `01`: noise
- `02`: square and noise
- `03`: nothing (apparently)
- `04`: envelope and square
- `05`: envelope and noise
- `06`: envelope and square and noise
- `07`: nothing
- `21xx`: set noise frequency. `xx` is a value between 00 and 1F.
- `22xy`: set envelope mode.
- `x` sets the envelope shape, which may be one of the following:
- `0: \___` decay
- `4: /___` attack once
- `8: \\\\` saw
- `9: \___` decay
- `A: \/\/` inverse obelisco
- `B: \¯¯¯` decay once
- `C: ////` inverse saw
- `D: /¯¯¯` attack
- `E: /\/\` obelisco
- `F: /___` attack once
- if `y` is 1 then the envelope will affect this channel.
- `23xx`: set envelope period low byte.
- `24xx`: set envelope period high byte.
- `25xx`: slide envelope period up.
- `26xx`: slide envelope period down.
- `29xy`: enable SSG auto-envelope mode.
- in this mode the envelope period is set to the channel's notes, multiplied by a fraction.
- `x` is the numerator.
- `y` is the denominator.
- if `x` or `y` are 0 this will disable auto-envelope mode.
- `30xx`: enable envelope hard reset.
- this works by inserting a quick release and tiny delay before a new note.
- `50xy`: set AM of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` determines whether AM is on.
- `51xy` set SL of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` is the value.
- `52xy` set RR of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` is the value.
- `53xy` set DT of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` is the value:
- 0: +0
- 1: +1
- 2: +2
- 3: +3
- 4: -0
- 5: -3
- 6: -2
- 7: -1
- `54xy` set RS of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` is the value.
- `55xy` set SSG-EG of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` is the value (0-8).
- values between 0 and 7 set SSG-EG.
- value 8 disables it.
- `56xx`: set DR of all operators.
- `57xx`: set DR of operator 1.
- `58xx`: set DR of operator 2.
- `59xx`: set DR of operator 3.
- `5Axx`: set DR of operator 4.
- `5Bxx`: set D2R/SR of all operators.
- `5Cxx`: set D2R/SR of operator 1.
- `5Dxx`: set D2R/SR of operator 2.
- `5Exx`: set D2R/SR of operator 3.
- `5Fxx`: set D2R/SR of operator 4.

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papers/doc/7-systems/ym2608.md Normal file
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# Yamaha YM2608 (OPNA)
like YM2203, but with twice the FM channels, an ADPCM channel and built-in drums ("rhythm")!
it was one of the available sound chips for the PC-98 series of computers.
the YM2610 (OPNB) and YM2610B chips are very similar to this one, but the built-in drums have been replaced with 6 sample channels.
# 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.
- `18xx`: toggle extended channel 3 mode.
- 0 disables it and 1 enables it.
- only in extended channel 3 system.
- `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.
- `20xx`: set SSG channel mode. `xx` may be one of the following:
- `00`: square
- `01`: noise
- `02`: square and noise
- `03`: nothing (apparently)
- `04`: envelope and square
- `05`: envelope and noise
- `06`: envelope and square and noise
- `07`: nothing
- `21xx`: set noise frequency. `xx` is a value between 00 and 1F.
- `22xy`: set envelope mode.
- `x` sets the envelope shape, which may be one of the following:
- `0: \___` decay
- `4: /___` attack once
- `8: \\\\` saw
- `9: \___` decay
- `A: \/\/` inverse obelisco
- `B: \¯¯¯` decay once
- `C: ////` inverse saw
- `D: /¯¯¯` attack
- `E: /\/\` obelisco
- `F: /___` attack once
- if `y` is 1 then the envelope will affect this channel.
- `23xx`: set envelope period low byte.
- `24xx`: set envelope period high byte.
- `25xx`: slide envelope period up.
- `26xx`: slide envelope period down.
- `29xy`: enable SSG auto-envelope mode.
- in this mode the envelope period is set to the channel's notes, multiplied by a fraction.
- `x` is the numerator.
- `y` is the denominator.
- if `x` or `y` are 0 this will disable auto-envelope mode.
- `30xx`: enable envelope hard reset.
- this works by inserting a quick release and tiny delay before a new note.
- `50xy`: set AM of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` determines whether AM is on.
- `51xy` set SL of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` is the value.
- `52xy` set RR of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` is the value.
- `53xy` set DT of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` is the value:
- 0: +0
- 1: +1
- 2: +2
- 3: +3
- 4: -0
- 5: -3
- 6: -2
- 7: -1
- `54xy` set RS of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` is the value.
- `55xy` set SSG-EG of operator.
- `x` is the operator (1-4). a value of 0 means "all operators".
- `y` is the value (0-8).
- values between 0 and 7 set SSG-EG.
- value 8 disables it.
- `56xx`: set DR of all operators.
- `57xx`: set DR of operator 1.
- `58xx`: set DR of operator 2.
- `59xx`: set DR of operator 3.
- `5Axx`: set DR of operator 4.
- `5Bxx`: set D2R/SR of all operators.
- `5Cxx`: set D2R/SR of operator 1.
- `5Dxx`: set D2R/SR of operator 2.
- `5Exx`: set D2R/SR of operator 3.
- `5Fxx`: set D2R/SR of operator 4.

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papers/doc/7-systems/ym2610b.md
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@ -16,9 +16,9 @@ it is backward compatible with the original chip.
- `16xy`: set multiplier of operator.
- `x` is the operator (1-4).
- `y` is the mutliplier.
- `18xx`: toggle extended channel 2 mode.
- `18xx`: toggle extended channel 3 mode.
- 0 disables it and 1 enables it.
- only in extended channel 2 system.
- only in extended channel 3 system.
- `19xx`: set attack of all operators.
- `1Axx`: set attack of operator 1.
- `1Bxx`: set attack of operator 2.
@ -95,4 +95,4 @@ it is backward compatible with the original chip.
- `5Cxx`: set D2R/SR of operator 1.
- `5Dxx`: set D2R/SR of operator 2.
- `5Exx`: set D2R/SR of operator 3.
- `5Fxx`: set D2R/SR of operator 4.
- `5Fxx`: set D2R/SR of operator 4.