Registers #
| Old3DS | Name | Address | Width | Used by |
|---|---|---|---|---|
| Yes | I2S1_CNT | 0x10145000 | 2 | Codec sysmodule, AgbBg, TwlBg |
| Yes | I2S2_CNT | 0x10145002 | 2 | Codec sysmodule, AgbBg, TwlBg |
I2S1_CNT #
| Bit | Description |
|---|---|
| 0-5 | DSP volume (doesn’t affect csnd). |
| 6-11 | GBA hardware master volume. And DSi too? |
| 12 | Unknown purpose. Maybe direction for microphone input? |
| 13 | I2S frequency. 0=32.728498046875 kHz, 1=47.605088068181818181818 kHz. |
| 14 | First MCLK output. 0=8.3784955 MHz, 1=16.756991 MHz. |
| 15 | Enable (0=Disabled, 1=Enabled) |
This I2S line is used the DSP, GBA hardware and microphone.
This is usually set to 0xC800 or 0xC820 when the DSP is active.
I2S2_CNT #
| Bit | Description |
|---|---|
| 0-12 | Unused (0). |
| 13 | I2S frequency. 0=32.728498046875 kHz, 1=47.605088068181818181818 kHz. |
| 14 | Second MCLK output. Connected to the CODEC chip. 0=8.3784955 MHz, 1=16.756991 MHz. |
| 15 | Enable (0=Disabled, 1=Enabled) |
This I2S line is used by CSND.
Usually set to 0xE000.