mirror of
https://github.com/tildearrow/furnace.git
synced 2024-11-19 11:05:11 +00:00
27 lines
1.3 KiB
Markdown
27 lines
1.3 KiB
Markdown
|
# OKI MSM5232
|
||
|
|
|
||
|
|
a rather primitive (but powerful) sound generator chip used in some arcade boards and even synthesizers (like Korg Poly-800).
|
||
|
|
|
||
|
|
it has 8 channels in 2 groups (of 4 channels each). each group can be configured with an envelope and the ability to produce 2', 4', 8' and/or 16' square/noise overtones on 8 outputs (four (2', 4', 8' and 16') per group).
|
||
|
|
|
||
|
|
however, this chip cannot entirely produce sound alone. it has to be paired with either an external envelope generator or capacitors to assist the internal envelope generator.
|
||
|
|
|
||
|
|
it also has no fine tune whatsoever. the frequency resolution is exactly a semitone.
|
||
|
|
|
||
|
|
Furnace implements this chip in a way that allows the following features:
|
||
|
|
- internal (capacitors) or external (volume macro) envelope modes per group
|
||
|
|
- the ability to change the volume of each output (this can be used to generate saw waves if you set each part/overtone's volume to exactly half of the previous one)
|
||
|
|
- global fine tune
|
||
|
|
- global vibrato (some arcade boards played with the clock input to simulate vibrato)
|
||
|
|
|
||
|
|
# effects
|
||
|
|
|
||
|
|
- `10xy`: set group control.
|
||
|
|
- `x` sets sustain mode.
|
||
|
|
- `y` is a 4-bit mask which toggles overtones.
|
||
|
|
- `11xx`: set noise mode.
|
||
|
|
- `12xx`: set group attack (0 to 5).
|
||
|
|
- only in internal (capacitor-based) envelope mode.
|
||
|
|
- `13xx`: set group decay (0 to 11).
|
||
|
|
- only in internal (capacitor-based) envelope mode.
|