mirror of
https://github.com/tildearrow/furnace.git
synced 2024-11-02 02:52:40 +00:00
81 lines
3.4 KiB
Markdown
81 lines
3.4 KiB
Markdown
# Commodore 64
|
|
|
|
a home computer with a synthesizer-grade sound chip of which people took decades to master. three oscillators with four selectable waveforms, ring modulation, oscillator sync, multi-mode filter and ADSR envelope.
|
|
|
|
very popular in Europe and mostly due to the demoscene, which stretched the machine's limbs to no end.
|
|
|
|
two versions of aforementioned chip exist - 6581 (original chip) and 8580 (improved version with working waveform mixing and somewhat more consistent filter curves).
|
|
|
|
## effects
|
|
|
|
- `10xx`: **change wave.** the following values are accepted:
|
|
- `00`: nothing
|
|
- `01`: triangle
|
|
- `02`: saw
|
|
- `03`: triangle and saw
|
|
- `04`: pulse
|
|
- `05`: pulse and triangle
|
|
- `06`: pulse and saw
|
|
- `07`: pulse and triangle and saw
|
|
- `08`: noise
|
|
- `11xx`: **set coarse cutoff.** `xx` may be a value between `00` and `64`.
|
|
- _this effect only exists for compatibility reasons, and its use is discouraged._
|
|
- use effect `4xxx` instead.
|
|
- `12xx`: **set coarse duty cycle.** `xx` may be a value between `00` and `64`.
|
|
- _this effect only exists for compatibility reasons, and its use is discouraged._
|
|
- use effect `3xxx` instead.
|
|
- `13xx`: **set resonance.** `xx` may be a value between `00` and `0F`.
|
|
- `14xx`: **set filter mode.** the following values are accepted:
|
|
- `00`: filter off
|
|
- `01`: low pass
|
|
- `02`: band pass
|
|
- `03`: low+band pass
|
|
- `04`: high pass
|
|
- `05`: band reject/stop/notch
|
|
- `06`: high+band pass
|
|
- `07`: all pass
|
|
- `15xx`: **set envelope reset time.**
|
|
- this is the amount of ticks the channel turns off before a note occurs in order to reset the envelope safely.
|
|
- if `xx` is 0 or higher than the song speed, the envelope will not reset.
|
|
- `1Axx`: **disable envelope reset for this channel.**
|
|
- `1Bxy`: **reset cutoff**:
|
|
- if `x` is not 0: on new note
|
|
- if `y` is not 0: now
|
|
- this effect is not necessary if the instrument's cutoff macro is absolute.
|
|
- `1Cxy`: **reset duty cycle**:
|
|
- if `x` is not 0: on new note
|
|
- if `y` is not 0: now
|
|
- this effect is not necessary if the instrument's duty macro is absolute.
|
|
- `1Exy`: **change additional parameters.**
|
|
- _this effect only exists for compatibility reasons, and its use is discouraged._
|
|
- `x` may be one of the following:
|
|
- `0`: attack (`y` from `0` to `F`)
|
|
- `1`: decay (`y` from `0` to `F`)
|
|
- `2`: sustain (`y` from `0` to `F`)
|
|
- `3`: release (`y` from `0` to `F`)
|
|
- `4`: ring modulation (`y` is `0` or `1`)
|
|
- `5`: oscillator sync (`y` is `0` or `1`)
|
|
- `6`: disable channel 3 (`y` is `0` or `1`)
|
|
- `20xy`: **set attack/decay.**
|
|
- `x` is the attack.
|
|
- `y` is the decay.
|
|
- `21xy`: **set sustain/release.**
|
|
- `x` is the sustain.
|
|
- `y` is the release.
|
|
- `3xxx`: **set duty cycle.** `xxx` range is `000` to `FFF`.
|
|
- `4xxx`: **set cutoff.** `xxx` range is `000` to `7FF`.
|
|
|
|
## info
|
|
|
|
this chip uses the [C64](../4-instrument/c64.md) instrument editor.
|
|
|
|
## channel status
|
|
|
|
the following icons are displayed when channel status is enabled in the pattern view:
|
|
|
|
- channel is silent:
|
|
-  it's not
|
|
-  gate bit disabled
|
|
-  gate bit disabled and test bit enabled
|
|
-  test bit enabled
|
|
-  ch3off enabled in filter mode
|