Sega Master System / Game Gear (SN76489)
Activate with chip sms (or chip gg / chip gamegear for Game Gear–oriented stereo). Optional region: chip sms ntsc (default) or chip sms pal.
Status: Beta.
Channels
| Channel | BeatBax type | Hardware |
|---|---|---|
| 1 | tone1 | Tone 1 (square, 10-bit period) |
| 2 | tone2 | Tone 2 |
| 3 | tone3 | Tone 3 |
| 4 | noise | 15-bit LFSR (white or periodic) |
There are no hardware envelopes or LFO — articulation uses software macros and inline effects.
Instrument fields
Common
| Field | Description | Range |
|---|---|---|
vol | Constant volume | 0–15 (0 = loudest, 15 = silent) |
vol_env | Volume envelope macro | [0-15,…|loop] |
gg:pan / gg_pan | Game Gear stereo pan | L, C, or R |
Tone (tone1–tone3)
| Field | Description |
|---|---|
arp_env | Arpeggio macro (semitone offsets) |
pitch_env | Pitch bend macro (semitone offsets) |
Noise
| Field | Description | Values |
|---|---|---|
noise_mode | LFSR feedback | white or periodic |
noise_rate | Clock divisor | 0, 1, 2, or tone3 |
noise_rate_env | Animated noise rate | [0-3,…|loop] |
noise_rate=tone3 locks the noise clock to Tone 3’s period (classic kick-follows-bass trick).
Walkthrough song
chip sms
bpm 150
inst lead type=tone1 vol=10 vol_env=[0,3,6,9,12,15]
inst harm type=tone2 vol=8 vol_env=[4,6,8,10]
inst bass type=tone3 vol=12
inst kick type=noise noise_mode=white noise_rate=2 vol_env=[0,6,10,15]
effect majorArp = arp:4,7
pat melody = C5<majorArp>:4 E5:4 G5:4 A5:4
pat bassline = C3 . G2 . A2 . F2 .
pat drums = kick . . kick kick . kick .
seq main = melody*4
seq bass_seq = bassline*4
seq drum_seq = drums*4
channel 1 => inst lead seq main
channel 2 => inst harm seq main:oct(-1)
channel 3 => inst bass seq bass_seq
channel 4 => inst kick seq drum_seq
play
Tips
- Volume is attenuation:
vol=0is loudest,vol=15is silent. - Use
vol_envfor attacks and decays (no hardware ADSR). - Lock kicks to the bass with
noise_rate=tone3on the noise instrument while Tone 3 plays the root. - For Game Gear stereo, use
chip ggandgg:pan=L|C|R.
Game Gear stereo
chip gg
bpm 140
inst lead type=tone1 vol=10 gg:pan=R
inst harm type=tone2 vol=8 gg:pan=L
inst bass type=tone3 vol=12 gg:pan=C
pat melody = C5:4 E5:4 G5:4 A5:4
channel 1 => inst lead pat melody
channel 2 => inst harm pat melody:oct(-1)
channel 3 => inst bass pat melody:oct(-2)
play
gg:pan is honoured in Web Audio / PCM and encoded in VGM via the 0x4F stereo command.
Effects
Supported (software-driven): arpeggio, pitch bend, vibrato, portamento, volume slide, tremolo, cut, pan / gg:pan. Hardware pulse sweep and multi-channel echo are not available — use pitch_env / bend instead of sweep.
Export
- VGM — primary tracker/register stream for SMS/GG: VGM export
- WAV / MIDI — common formats