MultiMediaCard (MMC) uses a 7-pin connector compatible with SD card sockets. MMC uses a serial SPI or MMC bus interface and was the predecessor to SD cards, now found mainly in embedded and automotive applications.
| Pin | Name | Function | Type |
|---|---|---|---|
| 1 | DAT3/CS | Data 3 or SPI chip select | I/O |
| 2 | CMD/DI | Command or SPI data in | BUS |
| 3 | VSS | Ground | GND |
| 4 | VDD | Supply voltage | PWR |
| 5 | CLK | Clock | BUS |
| 6 | VSS | Ground | GND |
| 7 | DAT0/DO | Data 0 or SPI data out | BUS |