furnace/papers/doc/7-systems/ym2612.md

# Yamaha YM2612

one of two chips that powered the Sega Genesis. It is a six-channel, four-operator FM synthesizer. Channel #6 can be turned into 8-bit PCM player.

For 0.6pre1, Furnace can now support advanced YM2612 features that  [Fractal](https://gitlab.com/Natsumi/Fractal-Sound) sound driver adds: two software-mixed PCM channels (variable pitch, sample offsets, max 13.7 khz rate) and CSM - ch3 special mode feature that can be abused to produce rudimentary speech synthesis.

# 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.
- `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.
- `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: -3
    - 1: -2
    - 2: -1
    - 3: 0
    - 4: 1
    - 5: 2
    - 6: 3
    - 7: -0
- `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.
update documentation 2022-01-16 01:10:43 -05:00			`# Yamaha YM2612`

somewhat improved system descriptions 2022-03-26 14:55:20 -04:00			`one of two chips that powered the Sega Genesis. It is a six-channel, four-operator FM synthesizer. Channel #6 can be turned into 8-bit PCM player.`
update documentation 2022-01-16 01:10:43 -05:00
docs update (#519) * docs update mentions of fractal, new chips documentation, and other minor stuff * add a link to the Fractal repo as suggested by @breakthetargets * better wording, less typos 2022-06-06 10:49:39 -04:00			`For 0.6pre1, Furnace can now support advanced YM2612 features that [Fractal](https://gitlab.com/Natsumi/Fractal-Sound) sound driver adds: two software-mixed PCM channels (variable pitch, sample offsets, max 13.7 khz rate) and CSM - ch3 special mode feature that can be abused to produce rudimentary speech synthesis.`

update documentation 2022-01-16 01:10:43 -05:00			`# 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.`
			- `18xx`: toggle extended channel 3 mode.
			`- 0 disables it and 1 enables it.`
rename system to platform easier to understand 2022-01-16 01:17:30 -05:00			`- only in extended channel 3 system.`
update documentation 2022-01-16 01:10:43 -05:00			- `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.
document (NON-WORKING) extended op param effects 2022-05-02 19:15:51 -04:00			- `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:
the final part of extra FM effects 2022-05-04 18:39:22 -04:00			`- 0: -3`
			`- 1: -2`
			`- 2: -1`
			`- 3: 0`
			`- 4: 1`
			`- 5: 2`
			`- 6: 3`
			`- 7: -0`
document (NON-WORKING) extended op param effects 2022-05-02 19:15:51 -04:00			- `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.
docs update (#519) * docs update mentions of fractal, new chips documentation, and other minor stuff * add a link to the Fractal repo as suggested by @breakthetargets * better wording, less typos 2022-06-06 10:49:39 -04:00			- `5Fxx`: set D2R/SR of operator 4.