SNDEX
The DSi has extended the sound memory mapped I/O interface.
ARM7 IO REGISTERS
| ADDRESS | WIDTH (bytes) | NAME |
|---|---|---|
| 0x04004700 | 2 | REG_SNDEXCNT |
| BIT | DESCRIPTION |
|---|---|
| 3-0 | NITRO/DSP ratio, valid range is 0 to 8. |
| 13 | I2S frequency, 0=32.73 kHz, 1=47.61 kHz |
| 14 | Mute status |
NITRO/DSP ratio
The DSP can generate sound output aswell, alongside the old NITRO sound mixer. The following settings configure the ratio between DSP and NITRO mixer output:
| Setting | Description |
|---|---|
| 0 | DSP sound 8/8, NITRO sound 0/8 (=DSP sound only) |
| 1 | DSP sound 7/8, NITRO sound 1/8 |
| 2 | DSP sound 6/8, NITRO sound 2/8 |
| 3 | DSP sound 5/8, NITRO sound 3/8 |
| 4 | DSP sound 4/8, NITRO sound 4/8 |
| 5 | DSP sound 3/8, NITRO sound 5/8 |
| 6 | DSP sound 2/8, NITRO sound 6/8 |
| 7 | DSP sound 1/8, NITRO sound 7/8 |
| 8 | DSP sound 0/8, NITRO sound 8/8 (=NITRO sound only) |