NES (Ricoh 2A03)

BeatBax includes a built-in NES APU. Activate it with chip nes (or chip famicom) at the top of your song. Optional region: chip nes ntsc (default) or chip nes pal.

Status: Stable.

The main Tutorial is Game Boy–focused. This page covers NES-specific channels, instruments, and macros.

Channels

Channel	BeatBax type	Description
1	pulse1	Melody / lead; duty + hardware sweep
2	pulse2	Harmony / counter-melody
3	triangle	Bass; no hardware volume control
4	noise	Percussion; 16 fixed noise “pitches”
5	dmc	Delta-encoded sample playback

Instrument fields

chip nes
bpm 150

; Pulse channels — duty, envelope, optional hardware sweep
inst lead   type=pulse1  duty=25   env=13,down   env_period=2
inst harm   type=pulse2  duty=50   env=10,down   env_period=4

; Sweep-driven pitch slide (Pulse 1 and Pulse 2 both have hardware sweep)
inst sweep  type=pulse1  duty=25   env=13,down   sweep_en=true  sweep_period=3  sweep_dir=down  sweep_shift=2

; Triangle — no hardware volume; use linear= for short percussive pings
inst bass      type=triangle
inst tri_kick  type=triangle  linear=4

; Noise — 16 fixed noise frequencies
inst kick   type=noise  noise_mode=normal  noise_period=12  env=15,down  env_period=3
inst snare  type=noise  noise_mode=normal  noise_period=6   env=14,down  env_period=1
inst hihat  type=noise  noise_mode=normal  noise_period=3   env=8,down   env_period=0

; DMC sample playback
inst bass_hit  type=dmc  dmc_rate=7  dmc_loop=false  dmc_sample="@nes/bass_c2"

Key differences from Game Boy:

• env_period controls hardware envelope decay (0 = fastest, 15 = slowest) separately from the initial level in env
• Triangle has no hardware volume; vol=0 is a software mute, any other value = full amplitude
• Noise pitch is determined by noise_period (0–15), not by the note name in the pattern
• Channel 5 (DMC) plays sample files, not synthesised tones

Named instrument tokens

Add note= to use the instrument name as a pattern token (useful for drums):

inst kick  type=noise  noise_mode=normal  noise_period=12  env=15,down  env_period=3  note=C5
inst snare type=noise  noise_mode=normal  noise_period=6   env=14,down  env_period=1  note=C5
inst hihat type=noise  noise_mode=normal  noise_period=3   env=8,down   env_period=0  note=C5

pat beat = kick . snare . kick . hihat hihat

Software macros

Per-frame (60 Hz) envelope sequences (FamiTracker / FamiStudio style):

Macro	Applied to	Values	Effect
vol_env	pulse1, pulse2, noise	0–15 per frame	Volume automation; overrides hardware env decay
arp_env	pulse1, pulse2, triangle	semitone offset per frame	Rapid arpeggio shimmer
pitch_env	pulse1, pulse2, triangle	semitone offset per frame	Pitch rip / fall-in
duty_env	pulse1, pulse2	0–3 per frame	Duty cycle modulation

Syntax: macro_name=[v0,v1,…] — play once and hold the last value. Add |N to loop from index N:

chip nes
bpm 120

inst lead  type=pulse1  duty=25  vol=10  pitch_env=[3,2,1,0,0,0,0,0]
inst swell type=pulse1  duty=50  vol_env=[1,2,3,4,5,6,7,8,9,10|9]
inst chord type=pulse2  duty=50  vol=8   arp_env=[0,4,7|0]
inst wah   type=pulse1  duty=50  vol=10  duty_env=[2,2,2,2,2,2,2,2,0,0,0,0,0,0,0,0|0]
inst kick  type=noise  noise_mode=normal  noise_period=12  vol_env=[15,12,8,4,2,1]  note=C5

pat melody = C5 . E5 . G5 . E5 .
pat beat   = kick . kick . kick . kick .

channel 1 => inst lead  seq melody
channel 2 => inst chord seq melody
channel 4 => inst kick  seq beat

play

One macro frame = 1/60 s on NTSC, regardless of BPM. If vol_env is present, hardware env decay is not applied.

Export

• FamiTracker text
• WAV / MIDI

See also

• Sound Chip Plugins overview
• Game Boy tutorial
• Example macros: songs/features/nes/nes_macro_*.bax in the toolchain repo