mirror of
https://github.com/tildearrow/furnace.git
synced 2024-11-27 06:53:01 +00:00
23 lines
1.3 KiB
Markdown
23 lines
1.3 KiB
Markdown
# Konami VRC6
|
|
|
|
the most popular expansion chip to the Famicom's sound system.
|
|
|
|
the chip has 2 pulse wave channels and one sawtooth channel.
|
|
volume register is 4 bit for pulse wave and 6 bit for sawtooth, but sawtooth output is corrupted when volume register value is too high. because this register is actually an 8 bit accumulator, its output may wrap around.
|
|
|
|
for that reason, the sawtooth channel has its own instrument type. setting volume macro and/or pattern editor volume setting too high (above 42/2A) may distort the waveform.
|
|
|
|
pulse wave duty cycle is 8-level. it can be ignored and it has potential for DAC at this case: volume register in this mode is DAC output and it can be PCM playback through this mode.
|
|
Furnace supports this routine for PCM playback, but it consumes a lot of CPU time in real hardware (even if conjunction with VRC6's integrated IRQ timer).
|
|
|
|
# effects
|
|
|
|
these effects only are effective in the pulse channels.
|
|
|
|
- `12xx`: **set duty cycle.** range is `0` to `7`.
|
|
- `17xx`: **toggle LEGACY sample mode.**
|
|
- **this effect exists only for compatibility reasons! its use is NOT recommented. use Sample type instruments instead.**
|
|
|
|
# info
|
|
|
|
this chip uses the [VRC6](../4-instrument/vrc6.md), [VRC6 (saw)](../4-instrument/vrc6.md), and [Generic Sample](../4-instrument/sample.md) instrument editors.
|