MultiMedia Card (MMC)

The MultiMedia card has been Available since 1997. This was developed by the subsidiary Infineon Ingentix together with SanDisk. It has an internal controller.
Devices which can write and read SD memory cards are generally downward compatible to MMC cards. However, devices originally designed for MMC are not compatible with SD memory cards. To prevent damage and wrong use, the SD cards have a thicker casing as the MMC cards.


MMC Plus

In February 2004, the MMCA (Multimedia Card Association) presented a new standard. MMC 4.0, which is called MMC Plus. Owing to an increased bus width and higher clock rate (26 and 52 MHz) higher reading and writing speeds could also be achieved.


RS-MMC

The so-called RS-MMC (Reduced Size Multi Media Card) is a scaled down by half version of the MMC card, especially in the newer mobile phones used. This is also usable in normal MMC devices by the use of an adaptor.


Mobile RS-MMC-DV/MMC

Some newer devices provide only a supply voltage of 1.8 volts. Therefore, a dual-voltage card was necessary, the RS-DV-MMC (Reduced Size Multimedia Card Dual Voltage), or also MMC mobile called. These cards can be used with two different operating voltages, with either 1.8 volts (20mA) or with 3Volt (80mA).


MMC Micro

Since early 2005, there are also the micro-MMC memory cards. This variant is only one-third the size of the RS-MMC card. It works with an operating voltage of 1.8 volts or 3.3 volts.


General technical data of different types:

Size (WxHxD) mm, number of contacts, operating voltages:

 
MMC / MMC Plus 24 x 32 x 1.4 7 / 13 Contacts 3 / 3, 3Volt
RS-MMC/RS-MMC DV 24 x 18 x 1.4 7 Contacts 3.3 / 1,8-3,3 volts
MMC mobile 24 x 18 x 1.4 13 contacts 1.8 / 3.3 volts
MMC micro 12 x 14 x 1.1 10 contacts 1.8 / 3.3 volts

Realized Capacities:    2MB (MMC) to 8GB (MMC Plus)

Speeds:                
Read: 3 to about 15MB / s (MMC) (52MB / MMC Plus theoretically)
write: from 2.5 to approximately 16MB / s (45MB / MMC theoretically)

File systems: FAT16 to 2GB, FAT32 from 2GB