1.4 KiB
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 is0to7.17xx: 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 and VRC6 (saw) instrument editors.
chip config
the following options are available in the Chip Manager window:
- Clock rate: sets the rate at which the chip will run.