furnace/doc/7-systems/gba.md

Game Boy Advance

a portable video game console from Nintendo, succeeding the Game Boy.

it starts with the Game Boy sound hardware and adds two stereo sample audio channels which can be used directly ("DMA", hard-panned, usually used as left/right channels) or used in a software mixing driver (most games do this) in order to have multiple voices.

effects

• 10xx: change wave.

Game Boy Advance (MinMod)

this is the software mixing driver available in Furnace. it is written by Natt Akuma. it features echo and up to 16 voices.

• 10xx: change wave.
• 11xy: configure echo.
  • this effect is kinda odd. here's how to use it:
    • create an empty instrument and put a very high note of it in channel 1.
    • put 110x in the effect column.
    • set volume column to set feedback.
    • don't use the channel for anything else.
• 12xy: toggle invert.
  • x left channel.
  • y right channel.

info

this chip uses the GBA DMA and GBA MinMod instrument editors.

chip config

the following options are available in the Chip Manager window:

• DAC bit depth: sets the bit depth.

these options are available when using MinMod:

• Volume scale: scale volumes to prevent clipping/distortion.
• Mix buffers: sets how many mix buffers will be stored in memory. higher values result in longer echo.
• Channel limit: sets the number of channels that will be available. higher values use more CPU.
• Sample rate: sets the mixing rate. higher values use more CPU.