Compatible Sequence Instruments
From the latest draft of the manual:
FamiTracker already allows instruments to be used interchangeably on several chips to a certain degree in exported NSFs, namely those from 2A03, VRC6, N163, or 5B; these sound chips (and MMC5) share a unified sequence instrument type. Since version 0.3.13, 0CC-FamiTracker adds full tracker-side support for using these sequence instruments across expansion chips, while handling the duty/wave setting for the respective chip appropriately.
Instruments from the sound chips listed above can be used across these chips. Their volume, arpeggio, and (hi)-pitch sequences are processed according to the target chip configuration. The following rules for duty cycle conversion apply:
VRC6 duty cycles up to 12.5% become 12.5%, duty cycles from 43.75% to 50% become 50%, and the rest become 25%. N163 wave indices are processed as is. 5B duty cycles always become 50%. There is no special handling of the duty cycle value regarding the noise generator of 2A03 or 5B.
2A03 75% becomes 25%, the rest remain the same. N163 wave indices are processed as is. 5B duty cycles always become 50%. There is no special handling related to the sawtooth channel.
Non-N163 sequence instruments do not write to the wave buffer nor alter the current channel's wave parameters.
All non-5B instrument duty values enable square output, plus disable the envelope and noise outputs.
Duty conversion occurs only through duty/wave instrument sequences; the Vxx effect always modifies the duty cycle/wave index directly, without invoking any conversion method.
