View source for EMMC

{{Use dmy dates|date=May 2012}}
{{Infobox media
| name          = MultiMediaCard
| logo          = 
| image         = 15-04-29-MMC-Karte-RalfR-dscf4734-d.jpg
| caption       = 32&nbsp;[[Megabyte|MB]] MMCplus card
| type          = [[Memory card]]
| encoding      = 
| capacity      = Up to 512&nbsp;GB
| read          = 
| write         = 
| standard      = 
| owner         = [[JEDEC]]
| use           = Portable devices
| dimensions    = Standard: 32&nbsp;×&nbsp;24&nbsp;×&nbsp;1.4&nbsp;mm
| weight        = Standard: ~2.0 g
| extended from =
| extended to   = [[Secure Digital]] (SD)
}}

In  [[consumer electronics]], the '''MultiMediaCard''' ('''MMC''') is a [[memory card | memory-card]] standard used for [[solid-state storage]]. Unveiled in 1997 by  [[SanDisk]] and [[Siemens AG]],<ref>{{cite book|url =http://www.tomshardware.com/reviews/flash-removable-storage-ssd-drive,3626-3.html | website= TomsHardware.com | title= Upgrading And Repairing PCs 21st Edition | publisher= Que Publishing | author= Scott Mueller | isbn= 978-0789750006 }}</ref> 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 memory | flash]] technology. MMC is about the size of a postage stamp: 24&nbsp;mm × 32&nbsp;mm × 1.4&nbsp;mm.  MMC originally used a 1-[[bit]] [[serial interface]], but newer versions{{when?|date=March 2018}} 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.

Typically, an MMC operates as a storage medium for a portable device, in a form that can easily be removed for access by a [[Personal computer|PC]]. For example, a [[digital camera]] would use an MMC  for storing image files. Via an MMC reader (typically a small box that connects via [[USB]] or some other serial connection, although some can be found integrated into the computer itself), a user could transfer pictures taken with the digital camera to his or her computer. Modern computers, both laptops and desktops, often have SD slots, which can additionally read MMCs if the operating system drivers can.

MMCs are available in sizes up to and including 512&nbsp;[[Gigabyte|GB]]. They are used in almost every context in which [[memory card]]s are used, like [[mobile phone| cellular phone]]s, digital audio players, digital cameras and [[Personal digital assistant|PDA]]s. Since the introduction of SD cards, few companies build MMC slots into their devices (an exception is some mobile devices like the [[Nokia 9300]] communicator in 2004, where the smaller size of the MMC is a benefit), but the slightly thinner, pin-compatible MMCs can be used in almost any device that can use SD cards if the software/firmware on the device is capable.

While few companies build MMC slots into devices {{as of | 2018 | lc = on}} (SD cards are more common), the embedded MMC (eMMC) is still widely used in consumer electronics as a primary means of integrated storage in portable devices. It provides a low-cost flash-memory system with a built-in controller that can reside inside an [[Android (operating system)|Android]] or [[Microsoft Windows|Windows]] phone or in a low-cost PC and can appear to its host as a bootable device, in lieu of a more expensive form of solid-state storage, such as a traditional [[solid-state drive]].

==Open standard==
[[File:Four MMC cards front.jpg|thumb|Top of four types of MMC cards (clockwise from left): MMC, RS-MMC, MMCplus, MMCmobile, metal extender]]
[[File:01fourcardsrev.curve.jpg|thumb|Bottom of the same four cards]]

This technology is a standard available to any [[company (law)|company]] wanting to develop products based on it. There is no royalty charged for devices which host an MMC. A membership with the MMC Association must be purchased in order to manufacture the cards themselves.

As of July 2009, the latest specifications version 4.4 (dated March 2009) can be requested from the MMCA, and after registering with MMCA, can be downloaded free of charge. Older versions of the standard, as well as some optional enhancements to the standard such as MiCard and SecureMMC, must be purchased separately.

A highly detailed version is available on-line<ref>{{cite web |url=http://html.alldatasheet.com/html-pdf/141187/SAMSUNG/MC2GH512NMCA-2SA00/305/1/MC2GH512NMCA-2SA00.html |title=MC2GH512NMCA-2SA00 datasheet(1/102 Pages) SAMSUNG &#124; SAMSUNG MultiMediaCard |website=Html.AllDatasheet.com |date=2005-09-22 |accessdate=2013-11-13}}</ref> that contains essential information for writing an MMC driver.

As of 23 September 2008, the MMCA group has [https://web.archive.org/web/20080302013503/http://www.mmca.org/compliance/buy_spec/mmc_spec_v4_3/ turned over] all specifications to the [http://www.jedec.org JEDEC organization] including embedded MMC (e-MMC) and miCARD assets. [[JEDEC]] is an organization devoted to standards for the solid-state industry.

As of February 2015, the latest specifications version 5.1 can be requested from JEDEC, and after registering with JEDEC, can be downloaded free-of-charge. Older versions of the standard, as well as some optional enhancements to the standard such as MiCard and SecureMMC, must be purchased separately.

==Variants==

===RS-MMC===
In 2004, the '''Reduced-Size MultiMediaCard''' ('''RS-MMC''') was introduced as a smaller form factor of the MMC, about half the size: 24&nbsp;mm × 18&nbsp;mm × 1.4&nbsp;mm.  The RS-MMC uses a simple mechanical adapter to elongate the card so it can be used in any MMC (or SD) slot.  RS-MMCs are currently available in sizes up to and including 2&nbsp;[[Gigabyte|GB]].

The modern continuation of an RS-MMC is commonly known as '''MiniDrive''' ('''MD-MMC'''). A MiniDrive is generally a [[microSD]] card adapter in the RS-MMC form factor. This allows a user to take advantage of the wider range of modern MMCs available<ref>TheMiniDrive.com, http://www.TheMiniDrive.com. Extracted 23 April 2014.</ref> to exceed the historic 2&nbsp;[[gigabyte|GB]] limitations of older chip technology.

Implementations of RS-MMCs include [[Nokia]] and [[Siemens cellular telephones|Siemens]], who used RS-MMC in their [[Series 60]] [[Symbian]] [[smartphone]]s, the [[Nokia 770 Internet Tablet]], and generations 65 and 75 (Siemens). However, since 2006 all of Nokia's new devices with card slots have used [[miniSD]] or [[microSD]] cards, with the company dropping support for the MMC standard in its products. Siemens exited the mobile phone business completely in 2006. Siemens continue to use MMC for some [[Programmable logic controller|PLC]] storage leveraging MD-MMC advances.

===DV-MMC===
The Dual-Voltage MultimediaCard ('''DV-MMC''') is one of the first acceptable changes in MMC was the introduction of dual-voltage cards that can operate at 1.8&nbsp;V in addition to 3.3&nbsp;V. Running at lower voltages reduces the card's energy consumption, which is important in mobile devices. However, simple dual-voltage parts quickly went out of production in favour of MMCplus and MMCmobile which offer capabilities in addition to dual-voltage capability.

===MMCplus and MMCmobile===
The version 4.x of the MMC standard, introduced in 2005, brought in two very significant changes to compete against SD cards: ability to run at higher speeds (26&nbsp;MHz and 52&nbsp;MHz) than the original MMC (20&nbsp;MHz) or SD (25&nbsp;MHz, 50&nbsp;MHz) and a four- or eight-bit-wide [[Bus (computing)|data bus]].

Version 4.x full-size cards and reduced-size cards can be marketed as '''MMCplus''' and '''MMCmobile''' respectively.

Version 4.x cards are fully backward compatible with existing readers but require updated hardware/software to use their new capabilities; even though the four-bit-wide bus and high-speed modes of operation are deliberately electrically compatible with SD, the initialization protocol is different, so firmware/software updates are required to use these features in an SD reader.

===MMCmicro===
[[File:Mmc-micro.PNG|thumb|MMCmicro]]

'''MMCmicro''' is a micro-size version of MMC.  With dimensions of 14&nbsp;mm × 12&nbsp;mm × 1.1&nbsp;mm, it is even smaller and thinner than RS-MMC. Like MMCmobile, MMCmicro allows dual voltage, is backward compatible with MMC, and can be used in full-size MMC and SD slots with a mechanical adapter. MMCmicro cards have the high-speed and four-bit-bus features of the 4.x spec but not the eight-bit bus, due to the absence of the extra pins.<ref>{{cite web|url=http://www.samsung.com/Products/Semiconductor/FlashCard/MMC/micro_mmc.htm |title=Samsung Semiconductor Global Official Website |language=ru |publisher=Samsung.com |date= |accessdate=2013-11-13}}</ref>

It was formerly known as ''S-card'' when introduced by [[Samsung]] on 13 December 2004. It was later adapted and introduced in 2005 by the [[MultiMediaCard Association]] (MMCA) as the third form factor memory card in the ''MultiMediaCard'' family.<ref>allmemorycards.com, ''[http://www.allmemorycards.com/mmc-micro.htm MMCmicro]''. Extracted 22 April 2006.</ref>

MMCmicro appears very similar to [[microSD]] but the two formats are not physically compatible and have incompatible pinouts.

===MiCard===
The '''MiCard''' is a backward-compatible extension of the MMC standard with a theoretical maximum size of 2048&nbsp;GB (2&nbsp;TB) announced on 2 June 2007. The card is composed of two detachable parts, much like a microSD card with an SD adapter. The small memory card fits directly in a USB port while it also has MMC-compatible electrical contacts, which with an included electromechanical adapter fits in traditional MMC and SD card readers. To date, only one manufacturer (Pretec) has produced cards in this format.<ref name=micard>{{cite web
| title = Pretec Announces S-Diamond, 1st In the World to Implement miCARD Standard
| url = http://www.businesswire.com/portal/site/google/index.jsp?ndmViewId=news_view&newsId=20070604006489&newsLang=en
| accessdate = 21 January 2010 }}</ref>

Developed by [[Industrial Technology Research Institute]] of Taiwan, at the time of the announcement twelve [[Taiwan]]ese companies (including [[ADATA]] Technology, [[Asustek]], [[BenQ]], [[Carry Computer Eng. Co.]], [[C-One Technology]], [[DBTel]], [[Power Digital Card Co.]], and [[RiCHIP]]) had signed on to manufacture the new memory card. However, as of June 2011 none of the listed companies had released any such cards, and nor had any further announcements been made about plans for the format.

The card was announced to be available starting in the third quarter of 2007. It was expected to save the 12 Taiwanese companies who planned to manufacture the product and related hardware up to US$40 million in licensing fees, that presumably would otherwise be paid to owners of competing flash memory formats. The initial card was to have a capacity of 8&nbsp;[[Gigabyte|GB]], while the standard would allow sizes up to 2048&nbsp;GB. It was stated to have data transfer speeds of 480 [[Mbit/s]] (60 [[Mbyte/s]]), with plans to increase data throughput over time.

===SecureMMC===
An additional, optional, part of the MMC 4.x specification is a [[Digital rights management|DRM]] mechanism intended to enable MMC to compete with SD or [[Memory Stick]] in this area. Very little information is known{{Citation needed|date=December 2008}} about how SecureMMC works or how its DRM characteristics compare with its competitors.

===eMMC===
[[File:Samsung Galaxy Tab 2 10.1 - Samsung KLMAG2GE4A-A002-3955.jpg|thumb|eMMC KLMAG2GE4A-A002 inside the [[Samsung Galaxy Tab 2 10.1]].]]
The eMMC ([[embedded system|embedded]] MMC<ref>{{cite web|url=http://www.datalight.com/solutions/technologies/emmc/what-is-emmc|title=What is eMMC Memory – software support - Reliance Nitro|author=|date=|website=datalight.com}}</ref>) architecture puts the MMC components (flash memory plus controller) into a small [[ball grid array]] (BGA) IC package for use in circuit boards as an embedded non-volatile memory system. eMMC exists in 100, 153, 169 ball packages and is based on an 8-bit parallel interface.<ref>https://www.hyperstone.com Flash Memory Form Factors - The Fundamentals of Reliable Flash Storage, Retrieved 19. April 2018</ref>  This is noticeably different from other versions of MMC as this is not a user-removable card, but rather a permanent attachment to the circuit board. In the event of an issue stemming from either the memory or its controller, the entire PCB ([[Printed Circuit Board]]) would need to be replaced. eMMC also does not support the SPI-bus protocol.

Almost all mobile phones and tablets used this form of flash for main storage up to 2016, in 2016 [[Universal Flash Storage|UFS]] started to take control of the market. The latest version of the eMMC standard ([http://www.jedec.org/standards-documents/results/jesd84-b51 JESD84-B51]) by JEDEC is version 5.1 released February 2015, with speeds rivaling discrete [[Serial ATA|SATA]]-based SSDs (400 MB/s).<ref>{{cite web|url=http://www.jedec.org/standards-documents/technology-focus-areas/flash-memory-ssds-ufs-emmc/e-mmc |title=e.MMC v5.1 |publisher=JEDEC |date= |accessdate=2015-08-21}}</ref>

===Others===
Seagate, Hitachi and others are in the process of releasing [[Small Form Factor committee|SFF]] hard disk drives with an interface called [[CE-ATA]]. This interface is electrically and physically compatible with MMC specification. However, the command structure has been expanded to allow the host controller to issue [[AT Attachment|ATA]] commands to control the hard disk drive.

===Table===
{{main|Comparison of memory cards}}
{{Comparison of memory cards}}

==References==
{{Reflist|30em}}

==External links==
{{Commons category|Multi Media Card}}

===Organizations===
* [http://www.jedec.org/ JEDEC] - Solid State Technology Association

===Specifications===
* [http://www.jedec.org/sites/default/files/docs/JESD84-A44.pdf eMMC (Embedded MMC) Standard MMCA 4.4 (JESD84-A44)(March 2009)] {{Registration required}}
* [http://www.jedec.org/sites/default/files/docs/MO-277A.pdf MMCplus 13 Pin Full Size MultiMediaCard (MMC) Outline (MO-277A)] {{Registration required}}
* [http://www.jedec.org/sites/default/files/docs/MO-278A.pdf MMCmobile 13 Pin Reduced Size MultiMediaCard (MMC) Outline (MO-278A)] {{Registration required}}
* [http://www.jedec.org/sites/default/files/docs/MO-279A.pdf MMCmicro 10 Pin Micro Size MultiMediaCard (MMC) Outline (MO-279A)] {{Registration required}}

===Other===
* [http://www.sandisk.com/Assets/File/OEM/Manuals/ProdManRS-MMCv1.3.pdf Sandisk OEM Manual for MMC and RS-MMC (PDF)]
* [https://web.archive.org/web/20071010143502/http://www.kingmaxdigi.com/product/MMC.pdf KingMax MMC technical document (PDF)]
* [http://www.hardwarebook.info/MMC MMC pinout (tech.)]
* [http://www.hardwarebook.info/MMCplus MMCplus pinout (tech.)]

{{Memory Cards}}

[[Category:Open standards]]
[[Category:SanDisk]]
[[Category:Siemens]]
[[Category:Computer-related introductions in 1997]]