Used to start/stop internal sound effect, start/stop sound using internal tone data.
Byte Content
0 Command*8+Length (fixed length=1)
1 Sound Effect A (Port 1) Decrescendo 8-bit Sound Code
2 Sound Effect B (Port 2) Sustain 8-bit Sound Code
3 Sound Effect Attributes
Bit 0-1 - Sound Effect A Pitch (0..3=Low..High)
Bit 2-3 - Sound Effect A Volume (0..2=High..Low, 3=Mute on)
Bit 4-5 - Sound Effect B Pitch (0..3=Low..High)
Bit 6-7 - Sound Effect B Volume (0..2=High..Low, 3=Not used)
4 Music Score Code (must be zero if not used)
5-F Not used (zero)
See Sound Effect Tables below for a list of available pre-defined effects.
Notes:
- Mute is only active when both bits D2 and D3 are 1.
- When the volume is set for either Sound Effect A or Sound Effect B, mute is turned off.
- When Mute on/off has been executed, the sound fades out/fades in.
- Mute on/off operates on the (BGM) which is reproduced by Sound Effect A, Sound Effect B, and the Super NES APU. A "mute off" flag does not exist by itself. When mute flag is set, volume and pitch of Sound Effect A (port 1) and Sound Effect B (port 2) must be set.
Used to transfer sound code or data to SNES Audio Processing Unit memory (APU-RAM).
Byte Content
0 Command*8+Length (fixed length=1)
1-F Not used (zero)
The sound code/data is sent by VRAM-Transfer (4 KBytes). All 16-bit values are little-endian.
000-001 Size of transfer data
002-003 Destination address in S-APU RAM (typically $2B00, see below)
004-XXX Data to be transferred
X+1-X+2 "End marker" (???), should be $0000
X+3-X+4 S-APU jump address, should be $0400
X+5-FFF Remaining bytes ignored
Possible destinations in APU-RAM are:
| Memory range | Description |
|---|---|
| $0400-2AFF | APU-RAM Program Area (9.75KBytes) |
| $2B00-4AFF | APU-RAM Sound Score Area (8Kbytes) |
| $4DB0-EEFF | APU-RAM Sampling Data Area (40.25 Kbytes) |
This function may be used to take control of the SNES sound chip, and/or to access the SNES MIDI engine. In either case it requires deeper knowledge of SNES sound programming.
Below lists the digital sound effects that are pre-defined in the SGB BIOS, and which can be used with the SGB “SOUND” Command. Effect A and B may be simultaneously used. Sound Effect A uses channels 6 and 7, Sound Effect B uses channels 0, 1, 4 and 5. Effects that use less channels will use only the upper channels (eg. 4 and 5 for a B Effect with only two channels).
| Code | Description | Recommended pitch | Nb of channels used |
|---|---|---|---|
| 00 | Dummy flag, re-trigger | - | 2 |
| 01 | Nintendo | 3 | 1 |
| 02 | Game Over | 3 | 2 |
| 03 | Drop | 3 | 1 |
| 04 | OK ... A | 3 | 2 |
| 05 | OK ... B | 3 | 2 |
| 06 | Select...A | 3 | 2 |
| 07 | Select...B | 3 | 1 |
| 08 | Select...C | 2 | 2 |
| 09 | Mistake...Buzzer | 2 | 1 |
| 0A | Catch Item | 2 | 2 |
| 0B | Gate squeaks 1 time | 2 | 2 |
| 0C | Explosion...small | 1 | 2 |
| 0D | Explosion...medium | 1 | 2 |
| 0E | Explosion...large | 1 | 2 |
| 0F | Attacked...A | 3 | 1 |
| 10 | Attacked...B | 3 | 2 |
| 11 | Hit (punch)...A | 0 | 2 |
| 12 | Hit (punch)...B | 0 | 2 |
| 13 | Breath in air | 3 | 2 |
| 14 | Rocket Projectile...A | 3 | 2 |
| 15 | Rocket Projectile...B | 3 | 2 |
| 16 | Escaping Bubble | 2 | 1 |
| 17 | Jump | 3 | 1 |
| 18 | Fast Jump | 3 | 1 |
| 19 | Jet (rocket) takeoff | 0 | 1 |
| 1A | Jet (rocket) landing | 0 | 1 |
| 1B | Cup breaking | 2 | 2 |
| 1C | Glass breaking | 1 | 2 |
| 1D | Level UP | 2 | 2 |
| 1E | Insert air | 1 | 1 |
| 1F | Sword swing | 1 | 1 |
| 20 | Water falling | 2 | 1 |
| 21 | Fire | 1 | 1 |
| 22 | Wall collapsing | 1 | 2 |
| 23 | Cancel | 1 | 2 |
| 24 | Walking | 1 | 2 |
| 25 | Blocking strike | 1 | 2 |
| 26 | Picture floats on & off | 3 | 2 |
| 27 | Fade in | 0 | 2 |
| 28 | Fade out | 0 | 2 |
| 29 | Window being opened | 1 | 2 |
| 2A | Window being closed | 0 | 2 |
| 2B | Big Laser | 3 | 2 |
| 2C | Stone gate closes/opens | 0 | 2 |
| 2D | Teleportation | 3 | 1 |
| 2E | Lightning | 0 | 2 |
| 2F | Earthquake | 0 | 2 |
| 30 | Small Laser | 2 | 2 |
| 80 | Effect A, stop/silent | - | 2 |
Sound effect A is used for formanto sounds (percussion sounds).
| Code | Description | Recommended pitch | Nb of channels used |
|---|---|---|---|
| 00 | Dummy flag, re-trigger | - | 4 |
| 01 | Applause...small group | 2 | 1 |
| 02 | Applause...medium group | 2 | 2 |
| 03 | Applause...large group | 2 | 4 |
| 04 | Wind | 1 | 2 |
| 05 | Rain | 1 | 1 |
| 06 | Storm | 1 | 3 |
| 07 | Storm with wind/thunder | 2 | 4 |
| 08 | Lightning | 0 | 2 |
| 09 | Earthquake | 0 | 2 |
| 0A | Avalanche | 0 | 2 |
| 0B | Wave | 0 | 1 |
| 0C | River | 3 | 2 |
| 0D | Waterfall | 2 | 2 |
| 0E | Small character running | 3 | 1 |
| 0F | Horse running | 3 | 1 |
| 10 | Warning sound | 1 | 1 |
| 11 | Approaching car | 0 | 1 |
| 12 | Jet flying | 1 | 1 |
| 13 | UFO flying | 2 | 1 |
| 14 | Electromagnetic waves | 0 | 1 |
| 15 | Score UP | 3 | 1 |
| 16 | Fire | 2 | 1 |
| 17 | Camera shutter, formanto | 3 | 4 |
| 18 | Write, formanto | 0 | 1 |
| 19 | Show up title, formanto | 0 | 1 |
| 80 | Effect B, stop/silent | - | 4 |
Sound effect B is mainly used for looping sounds (sustained sounds).