These registers are used to access the system NAND and the inserted SD card. Both devices use the same interface. HCLK of the SDMMC controller is 67.027964 MHz (double of the DSi HCLK).
Registers #
| Old3DS | Name | Address | Width | Used by |
|---|---|---|---|---|
| Yes | EMMC_CMD | 0x10006000 | 2 | Boot9, NewKernel9Loader, Process9 |
| Yes | EMMC_PORTSEL | 0x10006002 | 2 | Port selection, 0 = SD card, 1 = NAND |
| Yes | EMMC_CMDARG0 | 0x10006004 | 2 | |
| Yes | EMMC_CMDARG1 | 0x10006006 | 2 | |
| Yes | EMMC_STOP | 0x10006008 | 2 | |
| Yes | EMMC_BLKCOUNT | 0x1000600a | 2 | |
| Yes | EMMC_RESP0-7 | 0x1000600c | 2*8 | |
| Yes | EMMC_STATUS0 | 0x1000601c | 2 | |
| Yes | EMMC_STATUS1 | 0x1000601e | 2 | |
| Yes | ? | 0x10006020 | 2 | |
| Yes | ? | 0x10006022 | 2 | |
| Yes | EMMC_CLKCTL | 0x10006024 | 2 | |
| Yes | EMMC_BLKLEN | 0x10006026 | 2 | |
| Yes | EMMC_OPT | 0x10006028 | 2 | |
| Yes | EMMC_FIFO | 0x10006030 | 2 | |
| Yes | EMMC_RESET | 0x100060E0 | 2 | |
The IO interface for SDMC/NAND seems to be very similar to the DSi; see libnds for 🔗 sample code and 🔗 documentation, and GBATEK for 🔗 better documentation.
3DS SDMC/NAND IO registers are located at 0x10006000 and apparently mirrored at 0x10007000. It seems the 0x10007000 mirror is never used on retail units.
EMMC_STATUS0 #
| Bit | Description |
|---|---|
| 3 | SD card removal flag (Set to 1 when SD card is removed) |
| 4 | SD card insertion flag (Set to 1 when SD card is inserted) |
| 5 | SD card insertion status (0 = missing, 1 = inserted) |
SD card insertion status #
Assertion happens around 250 ms after SD card insertion and/or enabling the EMMC hardware (delay could possibly be due to an SD bus timeout?).