EMMC Registers
| NAME | PHYSICAL ADDRESS | WIDTH |
|---|---|---|
| REG_SDCMD | 0x10006000 | 2 |
| REG_SD??? | 0x10006002 | 2 |
| REG_SDCMDARG0 | 0x10006004 | 2 |
| REG_SDCMDARG1 | 0x10006006 | 2 |
| REG_SDSTOP | 0x10006008 | 2 |
| REG_SDBLKCOUNT | 0x1000600a | 2 |
| REG_SDRESP0-7 | 0x1000600c | 2*8 |
| REG_SDSTATUS0 | 0x1000601c | 2 |
| REG_SDSTATUS1 | 0x1000601e | 2 |
| REG_SD??? | 0x10006020 | 2 |
| REG_SD??? | 0x10006022 | 2 |
| REG_SDCLKCTL | 0x10006024 | 2 |
| REG_SDBLKLEN | 0x10006026 | 2 |
| REG_SDOPT | 0x10006028 | 2 |
| REG_SDFIFO | 0x10006030 | 2 |
The IO interface for SDMC/NAND seems to be very similar to the DSi; see libnds for sample code and 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.