MultiMediaCard
The MultiMediaCard, officially abbreviated as MMC, is a memory card standard used for solid-state storage. Unveiled in 1997 by SanDisk and Siemens, MMC is based on a surface-contact low pin-count serial interface using a single memory stack substrate assembly, and is therefore much smaller than earlier systems based on high pin-count parallel interfaces using traditional surface-mount assembly such as CompactFlash. Both products were initially introduced using SanDisk NOR-based flash technology.
32 MB MMCplus card | |
| Media type | Memory card |
|---|---|
| Capacity | Up to 512 GB |
| Developed by | JEDEC |
| Dimensions | Standard: 32 × 24 × 1.4 mm |
| Weight | Standard: ~2.0 g |
| Usage | Portable devices |
| Extended to | Secure Digital (SD) |
| Released | 1997 |
MMC is about the size of a postage stamp: 32 mm × 24 mm × 1.4 mm. MMC originally used a 1-bit serial interface, but newer versions of the specification allow transfers of 4 or 8 bits at a time. MMC can be used in many devices that can use Secure Digital (SD) cards. MMCs may be available in sizes up to 16 gigabytes (GB).
They are used in almost every context in which memory cards are used, like cellular phones, digital audio players, digital cameras, and PDAs. Typically, an MMC operates as a storage medium for devices, in a form that can easily be removed for access by a PC via a connected MMC reader.
The eMMC (embedded MMC) is MMC for use in circuit boards as an embedded non-volatile memory system. This is not a user-removable card, but rather a permanent attachment to the printed circuit board.