multimedia card (MMC)
Multimedia Card(MMC) are small memory cards with dimensions of 32 mm x 24 mm, with a thickness of only 1.4 mm. These cards are used in MP3 players, handhelds, smartphones and digital camcorders. Multi Media Cards are available with storage capacities of up to 8 gigabytes( GB), data throughput of 2.5 MB/s and supply voltages of 2.7 V to 3.6 V. The service life is specified as 1,000,000 memory/erase cycles.
The portfolio of the MMC card was extended by three further versions in the 4.0 standard: MMC-Plus, MMC-Mobile and MMC-Micro. Further versions are the MMC- RS and MMC-plus-RS. The abbreviation "RS" stands for Reduced Size, i.e. MMC cards with smaller dimensions.
MMC-Plus is the successor version of the multimedia card. It has the same dimensions as the latter, its memory capacity has been increased to 1 GB, its data rate has been increased to 26 MB/s and the operating voltage has been reduced to 3.3 V or 1.8 V.
MMC Mobile has dimensions of 18 mm x 24 mm and is pin-compatible with the double-sized MMC-Plus and the SD card. MMC Mobile has the same features as the MMC-Plus.
MMC Micro was developed for smartphones and digital cameras and is characterized by dimensions of only 14 mm x 12 mm and is only 1.1, mm thin. The memory card is managed by the File Allocation Table FAT16 or FAT32. The data rate for readout is 10 MB/s, for write-in it is 7 MB/s. It is available with memory capacities of 16 GB. The operating voltages are 3.3 V or 1.8 V.
Another smaller version of the MMC card is the RS-MMC card, where the "RS" stands for Reduced Size. It is smaller than the MMC card and consumes less power. It was formerly used in mobile devices.
The original MMC card has a serial interface with 7 pins, MMC Plus cards have 13. The memory cards can be plugged into a PC card adapter and thus connected to the PC card bus. In addition, there are special card readers for flash memory that can handle several formats and can be connected directly to the USB interface.
The specifications for the multimedia card are worked out by the Multimedia Card Association( MMCA). There is a proprietary notation for Multi Media Card: MultiMediaCard. For embedded applications in mobile devices, the MMCA and JEDEC have standardized the embedded Multimedia Card( eMMC). In an eMMC card, an MMC interface, the flash memory and controllers are integrated in an FBGA package.