MMC
From HwB
MMC = MultiMedia Card.
MMC has been superseeded by MMCplus. Which is backward compatible with MMC, but has 13 pins instead of 7. Developed by Siemens and SanDisk in 1997.
Size is 32 x 24 x 1.4 mm.
Contents |
Pinout
MultiMedia Card Mode
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | RSV | Reserved for future use | |
| 2 | CMD |  PP) OD) |
Command / Response |
| 3 | VSS |  |
Supply voltage ground |
| 4 | VDD |  |
Supply voltage |
| 5 | CLK | |
Clock |
| 6 | VSS | |
Supply voltage ground |
| 7 | DAT | PP) |
Data |
Note: Direction is memory card relative to host.
PP) Push-pull.
OD) Open-drain.
SPI Mode
| Pin | Name | Dir | Description |
|---|---|---|---|
| 1 | CS | |
Chip Select |
| 2 | DI | PP) |
Data In |
| 3 | VSS | |
Supply voltage ground |
| 4 | VDD | |
Supply voltage |
| 5 | CLK | |
Clock |
| 6 | VSS | |
Supply voltage ground |
| 7 | DAT | PP) |
Data Out |
Note: Direction is memory card relative to host.
PP) Push-pull.
History
- MMC v1.0 (September 1996)
- MMC v2.11 (June 1999)
- SD Card based on this standard
- MMC v3.31 (May 2003)
- Dual Voltage Cards
- MMC v4.x (April 2005)
- Smaller form factor
- Larger bus (4 or 8 bits)
- Faster bus (26MHz or 52MHz)
- SecureMMC
- MMCplus (> 4GB)
- eMMC (December 2006)
Related connectors
Additional information
Sources
- Kingmax Digital Inc's MMC datasheet
- Presentation about FreeBSD's SD/MMC Implementation by Warner Losh