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Kingston memory cards with MMC and SD interfaces. Computer help mms memory cards

How to choose a memory card?

It is worth highlighting a number of points that affect the choice of a memory card:

Memory card capacity

It is important to know that the actual amount of memory that the card has differs from the theoretical maximum that is written on the packaging. This is due to the fact that part of the card is occupied by service information: file data, service information, information to protect the memory card from failures, etc. On average, the actual amount of memory is 10% less than promised.

Speed

Speed ​​is fun. The faster the card, the less time it takes to write data to the card. A fast card will allow the camera to take more pictures in a shorter amount of time. Super, Ultra, Pro, Xtream memory cards are faster than other cards. Per unit of speed is selected. The speed of the 133x card is twice as fast as the 66x card. The designation 1x means a speed of 150 KB per second.

Reliability

According to testing, xD and Compact Flash cards are the most secure. Modern cards The memory is designed for several write-rewrite cycles, which ensures the safety of data for a period of at least 5 years.

Protection

Many memory cards, such as SD, Memory Stick, have the ability to protect information from illegal use.

Memory card prices

Prices for memory cards vary accordingly depending on the parameters listed above and the "brand name".

Brand

The choice of manufacturer (brand) of memory cards often plays a big role for customers. Fan sentiment is especially strong among young people and amateur photographers. There is a huge amount of opinions, tests, disputes about which manufacturer of memory cards is the best! According to the results of some tests - the fastest Kingston memory cards, according to the results of other Transcend cards. Someone considers Microdia the most reliable brand, someone Sandisk. As in the case of mobile phones, there is no unequivocal opinion on this matter.

Types of memory cards

Compact Flash (CF)- one of the oldest and most common types of memory cards. The format was developed by SanDisk Corporation in 1994. Most digital cameras, PDAs, MP3 players and other devices support the Compact Flash card. The Compact Flash CF card is ideal for photography enthusiasts. In fact, no card can boast such speeds and volumes as the Compact Flash card. To date, Compact Flash cards have a capacity of 2 MB to 128 GB. The most popular "size" Compact Flash 16Gb and 32Gb. In terms of speed, the Compact Flash 600x and Compact Flash 667x are currently the fastest cards in the series. But not only the speed of Compact Flash became the key to its popularity. Compact Flash type has one of the most optimal volume/price ratios.

As technology has advanced, this format has evolved. CompactFlash Type II (CF Type II) characterized by an increased read / write speed and a slightly greater thickness. Digital equipment with a CompactFlash Type II slot also supports a Compact Flash card.

The most famous Compact Flash CF manufacturers are A-DATA, ATP, Canon, FujiFilm, Kingston Technology, Kodak, Lexar, Memorex, Olympus, Panasonic, PNY, Ritek, SanDisk, Samsung, Sony, Toshiba, Transcend, Verbatim Corporation, UMAX.

microdrive — it's not exactly a memory card, but rather a miniature hard drive. Compactflash Microdrive has a housing and a connection connector similar to Compact Flash II. However, the disadvantages of CF Microdrive - such as increased power consumption and heat dissipation, low performance, sensitivity to vibrations - are slowly pushing it out of the market. Of the pluses - the Microdrive card has a fairly low price in relation to its volume. The size of the compactflash Microdrive ranges between 170 MB and 8 GB. The Microdrive card is integrated into some devices: Apple iPod mini - 4GB and 6GB Hitachi Microdrive, HTC Athena 8GB Hitachi Microdrive, iriver H10 - 5GB and 6GB Seagate Microdrive, etc. The file system of the CF Microdrive is NTFS.

Secure Digital (SD) is a joint development of Panasonic, Toshiba and SanDisk. At the moment, Secure Digital card is one of the most common data storage formats. The advantages of the Secure Digital card are its small size, high write and read speed, low power consumption, the ability to protect the information stored on it from copying, accidental erasure or destruction, and mechanical strength. Standard for Secure Digital SD cards file system is FAT32. The maximum speed of the Secure Digital card is 300x (i.e. 45000 kB/s). Secure Digital memory does not exceed 4 GB.

The expansion of the Secure Digital card has led to the emergence of additional formats − Secure Digital HC (SDHC) with a maximum capacity of 32GB and Secure Digital XC (SDXC) up to 2TB.

For miniature technology developed formats miniSD(21.5x20x1.4 mm), microSD(11x15x1 mm) and microSDHC(11x15x1 mm), which have adapters (adapters) with which they can be inserted into any slot for a regular SD card. Cards of this size are usually used in cell phones, as their compactness allows not to increase the size and weight of modern devices.

miniSDHC(Mini Secure Digital High Capacity) - is an extension of the miniSD format and allows you to issue memory cards with a capacity of 4 GB or more. However, they are only compatible with MiniSDHC-enabled devices.

xD-Picture- developed in 2001 by well-known manufacturers of digital photographic equipment, Olympus and Fuji. Among the advantages of the xD-Picture card are its compactness, reliability, speed, and low power consumption. Cons: Together with the Sony Memory Stick, this is one of the most expensive memory cards out there. The xD memory card is only found in Olympus and Fuji digital cameras. In addition, xD Picture memory is suitable for storing digital movies. Compatibility: xD -> Compact Flash (with adapter).

There is an external adapter that allows xD-Picture cards to be used in the SmartMedia slot, but it does not fully fit into the SM slot. There is a limit on the size of the used xD card (128, sometimes - 256 MB), and there may also be limitations in the operation of the reader.

smart media is a portable flash memory card developed by Toshiba, Olympus and Fuji. At the moment, the SmartMedia card has almost completely disappeared from circulation. Very rarely there are only Japanese digital cameras (for example, Olympus) of the last years of release with support for Smart Media. But Olympus limits the functionality of non-native cards, and their purchase will cost significantly more. The advantages of the card include low price and compactness. The disadvantages are a small amount of built-in memory (128 MB SmartMedia cards are the limit), the lack of a memory controller to reduce the price, mechanical insecurity and a short service life (no more than 5 years). The SmartMedia memory card exists in two versions - 5 V and 3.3 V, they differ only in the position of the cut corner.

memory stick — Unique cards based on flash memory technology, developed by the world famous Sony company exclusively for its products. That is why Sony Memory Sticks are the most expensive cards on the market, sharing the first place with xD. Sony Memory Stick is not even one, but a whole family of memory cards. It also includes Memory Stick Pro, a faster option, and Memory Stick Duo, a smaller and more expensive card. Memory Stick Pro Duo are used in camcorders, digital cameras, personal computers, printers, game consoles PSP and some Sony Ericsson mobile phones.

The capacity of the Memory Stick has never exceeded 128 MB, as well as Memory Stick Duo(also no more than 128MB). More advanced in this matter Memory Stick PRO(1GB) and Memory Stick PRO Duo (8-16GB). All of them differ in size, however, there are special adapters for connecting modules of one type to a slot of another type.

Cards Memory Stick Pro-HG Duo were announced at the end of 2006. This is a high speed version of Memory stick PRO for use in HDTV cameras. And a little later - in 2008 - the Memory Stick PRO Duo Mark 2 card was released, the volume of which was 16 GB.

Micro Memory Stick- has a very small size (15 x 12.5 x 1.2 mm). Designed for use in Sony Ericsson mobile phones. The advantage of microMMC (besides its size) is that the information on it is protected from unauthorized copying.

MultiMediaCard (MMC)- became the first memory card designed specifically for use in mobile phones and players. MMC appeared in 1997 thanks to the efforts of Sandisk and Siemens. First MMC cards Memory systems were actively promoted by mobile phone manufacturers Nokia and Siemens. Advantages of MultiMedia Card - small size, as well as a solid mechanical design and low power consumption. Among the drawbacks of the Multi Media Card is the slow interface and rather high cost. The MMC multimedia card is mostly compatible with the later developed SD card and can be used instead of SD.

The development of the secure digital MultiMedia card has led to the creation of Reduced Size—Multi Media Card (RS-MMC). The RS-MMC memory card is half the size of a standard MMC card and weighs only 1g. An adapter is required to ensure compatibility with the existing MMC standard when using RS-MMC cards. In terms of speed, they are similar to MMC cards, the maximum capacity of which today is 2 GB. RS-MMC is found in some Nokia and Siemens models.

There is also a modification of these cards called DV-RS-MMC, this card consumes less power, as a result, the phone will have to be charged less often. It is also worth noting that some models of Nokia smartphones only support DV-RS-MMC cards Compatibility: RS-MMC \ DV-RS-MMC -> MMC -> SD (with adapter).

Memory cards MMC Plus appeared in 2005, their main difference from SD and MMC cards is high data transfer speed (up to 52 Mb/s). Map MMC Plus HC(High Capacity) is an extension of MMCPlus. The capacity of this model is 4GB. Distinctive feature MMCPlus HC is that it can only be used with compatible devices. And in devices without support, it works like a standard MMC.

microMMC- Designed for mobile devices with ECC support. (Error Checking and Correction - detection and correction of errors when writing / reading). The advantage is low power consumption, so the cell phone will not sit down so quickly.

MiCard (Multiple Interface card) is a multi-interface card developed by Taiwan's Industrial Technology Research Institute that is compatible with existing USB ports as well as MMC card slots. This is a new type of card that has the advantage of high data transfer rates (480 Mbps). MiCard is used to transfer data directly between a portable device and a desktop computer without connecting a card reader.

No sooner had we gotten used to cards that conform to the SD 1.1 specification (and most devices still only support the slower SD 1.0), a transition to SD 2.0 loomed on the horizon. It can be assumed that, as a result, 1.1 becomes a "passing" version, and you should not pay attention to it. In fact, everything is different. There is a feeling that the implementation of SD 2.0 will be even slower and more painful than the transition from 1.0 to 1.1 or even from MMC 3.0 to 4.x. Most likely, this process will resemble the transition from MMC to SD, which, by the way, did not end as a result - instead of the death of MMC, which was repeatedly predicted (including by me), this format, on the contrary, recently found a second wind. The reason is the same - the lack of backward compatibility of SD and SDHC (this logo will be worn by all cards that meet 2.0 specifications). If an SD 1.1 card can be safely used in conjunction with devices designed for SD 1.0 (albeit at a lower speed - as much as was possible in 1.0), the same applies to MMC 4.x / 3.0, then the SDHC card will work in the "normal" SD device will not. Thus, an SD 1.1 or MMCplus card could be bought for the future, but SDHC could not. At the same time, SDHC devices will be compatible (when available) with conventional SD cards, so the latter can be safely purchased. Not the fact that you will lose something later. Why? Let's see what SD 2.0 brings us.

Just a bug fix

The transition from SD 1.0 to 1.1 doubled the maximum speed, the transition from MMC 3.0 to 4.0 gave us, in fact, new cards, but what does SD 2.0 give? Officially, there are only two things - an increase in the maximum volume of cards and Class Speed ​​​​Rating. The second one is easier, so let's start with it.

As you know, manufacturers prefer to label memory cards by top speed reading, and according to the theoretically possible. Not all and not always, but in most cases we observe just that. The write speed, if indicated, is also the maximum, and even then not always, and only in the specifications and in small print. And the reading speed (the notorious "X") is most often indicated directly on the card in arshin (compared to the size of the card itself) letters. However, it is far from always at least close to the write speed (a vivid example is MLC chips, where the difference is several times by definition), and it is difficult to achieve high values ​​of the latter in the case of flash. Manufacturers do not indicate it - it is unprofitable. As a result, the purchased "high-speed" card can easily turn out to be slower than the "regular" one, which we have encountered more than once. At the same time, in many areas of application, reading speed is not very important (just think - photos after a vacation will be copied to a computer in 10 minutes, not 5: no one will die), while writing speed is critical. An example is the same cameras, where a low recording speed simply will not allow continuous shooting. The situation is even worse with video recording, where flash is gradually becoming one of the most commonly used media: low write speed will make shooting simply impossible due to the fact that most frames will “drop out” with an obvious end result. The first attempt to sort out the mess with markings was made by the MMC alliance: the MMCplus card must not only support the 4.x specification, but also have a minimum steady-state write speed of at least 2 MB / s. The SD association went even further by introducing three card classes: Class 2, Class 4 and Class 6. The numbers here are not abstract values, but the established minimum write speed - 2, 4 and 6 MB / s. The innovation is useful, but not so vital: our tests show that today the vast majority of even inexpensive cards are quite capable of handling a stream of 6 MB / s. On the other hand, it will become easier when buying: for example, if you know that SDHC Class 6 is required to fully realize the capabilities of a photo or video camera, then you should look for such a card without rummaging through test results and descriptions on manufacturers' websites. Of course, the possibility of abuse by the manufacturer remains in theory, but in this case, he will receive not only lamentations from the deceived user on various forums, but also persecution from the Association, which is unlikely to be done by anyone (even from small companies).

As for volume, the situation is simple and understandable. Officially, the capacity of today's SD cards cannot exceed 2 GB. The limitation is not physical, but logical: the reason for this is the file system used - FAT16. The latter also supports volumes over 2 GB, but with a non-standard cluster size, which most household equipment manufacturers will not do. And for SDHC, the official file system is FAT32, so the restriction is almost lifted. However, some upper frames have been included in the standard so far - 32 gigabytes, however, compact cards still grow and grow up to such a capacity (and prices keep falling :)). In the end, some of the formats support large volumes, but cards of at least 16 GB, not to mention 32 or 64, are not yet visible;) Thus, from this point of view, SDHC is an obvious step forward compared to SD . However, somewhat blurred by the fact that some hardware manufacturers have already mastered FAT32 support in SD 1.1. And manufacturers of memory cards responded to this with the release of SD-cards with a capacity of 4 gigabytes. Such cards even in our area already cost less than $100. They will subsequently work in technology with SDHC support (I remind you that there is compatibility in this direction), and no one will fix devices that do not support such cards anyway, since SDHC will definitely not work in them;)

This is what makes the transition from SD 1.1 to 2.0 different from the transition from 1.0 to 1.1. In the second case, we could simply buy new cards and wait for the appearance of new devices that will allow us to reveal all their capabilities. In the first one it is necessary first wait for the market to saturate with SDHC-enabled devices, and after buy cards, as they are useless for older devices. And even then, you can still use regular high-capacity SD cards, since they will work in the future. It is possible that in the present, but this particular device needs to be checked. So far on the SanDisk website, I have found only seven SDHC-compatible devices with all the consequences. It can be said that the 4 GB SDHC cards that have been actively announced recently are simply useless - you can buy a regular one of this capacity. When you want to get an eight gigabyte card, it's another matter: there will be no alternatives to SDHC. But first you need to purchase a device in which you can use such a card.

And how can this affect the "popular" volumes up to 2 GB? No way - SDHC-cards of such capacity are not planned. This segment of the market will remain the patrimony of SD 1.1, but many users at the current price level do not even need two gigabytes. That is why testing SD 1.1 cards continues to make sense, and this situation can last at least another year, or even more. The MMC alliance does not make any sudden movements after the appearance of version 4.1 specifications - first you need to master what the standard already allows (fortunately, the latest version of the specification was developed a little later than in the case of a competitor, and it was much more revolutionary than SD 1.1 - in as a result, quite standard MMC 4.x cards with a capacity of 8 GB have already been announced, and nothing in the standard had to be altered ;)). We are still mainly interested in cards compatible with SD 1.1 and MMC 4.1. We will study these again. The topic of today's article is representatives of several lines of flash cards from Kingston, which belong exactly to the two families mentioned. In addition to the manufacturer, they are related, by the way, also in capacity - all in gigabytes. For many applications, it is quite enough, and the price has already dropped to such a level that you can not deny yourself anything;)

Getting to know the test subjects

According to the chronology of creation and the alphabet, it is most logical to start with MMCplus - a direct descendant of those very old good MMC cards, with a capacity of a dozen or two megabytes, from which all branches of the family tree of both MMC and SD families began their "pedigree". But the rest, in fact, are side shoots, and MMCplus, I repeat once again, is direct, although in its content (and a little in form - the contact group is completely different) significantly different from its ancestor. However, we have seen a lot of cards of this standard, so I'll tell you that its real capacity, according to Everest, is 973 megabytes, and move on.

MMC cards were originally designed with an eye on maximum compactness, but time has shown that they are too big for some applications. A new shoot sprouted from the tree - RS-MMC cards, which looked like MMCs cut to length. Later, DV RS-MMC appeared on their basis, which differed in supporting the supply voltage not only 3.3 V, but also 1.8 V - since energy consumption is directly related to voltage, the need to reduce it in mobile devices is obvious. And after the appearance of the MMC 4.0 specifications, MMCmobile - DV RS-MMC with support for new operating modes was born. If you look from the other side, you can call these cards and RS-MMCplus, fortunately for full-size models it is also recommended (albeit optional) support for a voltage of 1.8 V. At first, all RS-modifications were noticeably inferior in capacity to the base ones (for purely technical reasons ), however, as technology advances, prices for high-density flash chips decrease, and user appetite grows ( Cell phones, where such cards are in use, have long been competing with digital players with considerable success and are getting closer to the patrimony of "digital soapboxes") the gap in the case of mass modifications has been shrinking more and more. However, I have not yet seen the announcement of MMCmobile for 8 GB, and MMCplus - no problem, but in the retail network (at least in Moscow), both cards are still limited to 2 GB. We, as I said, are testing a card with a capacity of 1 GB declared or (according to Everest) 988 MB real.

The Secure Digital standard originated from MMC a long time ago, and is not its direct descendant - the cards are similar, but, strictly speaking, they are not required to be compatible in any direction (however, thanks to consumer equipment manufacturers, we can often use both, but this is achieved by using two-standard controllers). Nominally, two versions of the specifications have changed (and they existed at different times), but, as I wrote at the beginning of the article, version 1.1 will not disappear anywhere in the near future, and it will never disappear from cards up to 2 GB. We are testing just a gigabyte card, and not a simple one, but an “extreme” one. However, according to Kingston, the speed limit is at 133x, and some manufacturers have mastered 150x, but the latter can mean anything in practice, and the promised 20 MB / s at least for read operations is now quite real. As far as they are real in our case - tests will show. Let me just say that an attempt to achieve technical perfection and create cards that are universal for all applications played a bad joke with Secure Digital: no one actually uses this secure one, and it eats up the capacity of the card. According to Everest, Kingston's 1GB SD card is only 941MB.

The use of flash cards in small-sized equipment, as I said, led to the flourishing of their smaller modifications. If the MMC alliance focused on RS-MMC / MMCmobile, then the alternative from the SD association was miniSD cards. It should be noted that Alliance's position is slightly better - in the case of MMC, the cards are physically and electrically compatible by connector. The SD association did not cut, but came up with a new form factor that is compatible with the "ancestor" only with the help of special adapters. And so the features are the same - reduced dimensions and reduced supply voltage. The capacity has been reduced for a long time, but now both SD and miniSD are equally up against the limitations of the standard, that is, 2 gigabytes (in practice, however, there is a difference - “non-standard” cards of twice the capacity in the case of SD exist, and no one makes such miniSD didn't risk it). By the way - the real capacity, which is the funniest thing, in our case, miniSD has more: 949 MB according to Everest :)

And now we will measure your boy- used to say the hero of one cult cartoon. Cards, of course, are not boys (and not girls either :)), and I am not the postman Pechkin, but without measurements in our time, too, nowhere.

Test Methodology

Testing was carried out on a computer with the following configuration:

• EpoX 8NPA SLI
• AMD Athlon 64 3200+ (512K L2)
• 1 GB PC3200 DDR SDRAM
• system hard drive Western Digital WD740GD
• Apacer MegaSteno AM230 card reader
• Windows XP Pro + SP2

To measure the parameters of the subjects, the program Lavalys Everest Ultimate Edition 2006 2.80 was used, or rather, the test of disk drives included in it.

Competitors

Since we have cards of different standards, the diagrams will show everything that we have previously tested on this card reader. At the same time, among other things, we will once again compare the capabilities of MMC 4. x and SD 1.1 with each other: nevertheless, we have not tested them so much to deny ourselves the pleasure :)

Reading tests

Nobody managed to repeat the record of the ultra-fast MMCplus card from Apacer in this case. Kingston MMCplus, judging by the results, supports only four data lines and a mandatory (from the point of view of the standard) clock frequency of 26 MHz. MMCmobile is noticeably faster (most likely, due to the utilization of the entire possible bus width), but it falls short of high-speed SD cards. On the other hand, both SD and miniSD cards reach the required speed of 133x, despite the fact that no one has declared a record speed for the latter.

The read access time for most cards has long been in the range of 0.5-1.5 ms. Our current subjects were no exception. As a funny grimace of fate, one can regard the fact that their results are arranged in alphabetical order, despite the alternation of formats in it :)

Write Tests

miniSD is noticeably behind the full-sized card, although it works quite quickly. SD showed exactly the same result as the 133x from Pretec - sometimes, it turns out, you can pay attention to the X's. In the MMCplus/MMCmobile pair, the positions have changed: judging by the speed, the second card uses MLC chips with all the consequences. And the first read and write speeds do not differ, which works in favor of the theory about the narrowness of the data bus itself - the flash microcircuits themselves would “catch” more, but they are not given.

With one exception, write access times are as expected. However, the exception deserves special mention: the write access time for SD Ultimate is lower than for the fastest hard drives, although the opposite is observed for most flash drives (as can be seen in the diagram). This result is not unique - the Pretec i-Disk Diamond flash drive also quickly “responds”. At this rate, soon all flash drives will overtake their magnetic counterparts in all performance parameters;) Still, the problem with a limited number of rewrite cycles will be solved, the price reduced and that's it - solid state drives will play a funeral march to their competitors :)

Real capacity

Above (in the description of the cards) I indicated it, but for the convenience of comparison I will repeat it in the table:

What conclusions can be drawn? First, you should not count on the declared capacity - the real one is noticeably less. Secondly, even within the framework of the products of one company of the same standard, it can differ markedly. Thirdly, what I paid attention to, the capacity of MMC cards, other things being equal, is higher than that of SD: nothing is given for free in this world. The difference between the minimum and maximum in today's testing reaches 47 MB ​​- quite recently, cards with a lower total capacity were a very mass commodity (still often smaller ones are included in a set of cameras) ;)

Prices

The table below shows the average retail prices of cards tested today in Moscow, relevant at the time you read this article:

Total

Not so long ago we saw that MMC cards can be much faster than SD cards. Today we saw not the first confirmation that they are not always faster, even in ideal conditions. In old equipment, everything will be even worse for MMC - high-speed SD can lose two times in speed, while high-speed MMC can “sink” by more than an order of magnitude.

As for the Kingston cards themselves, all of them demonstrate quite decent speed indicators, even when they didn't promise it (when they promised, the reality matches the promises). At the same time, they are distinguished by a democratic price, which, coupled with the popularity of this brand and a good warranty period, makes them a very reasonable candidate for purchase. All. And which ones - depends on your preferences (or rather, the preferences of your digital equipment) in terms of tires and form factors.

Multimedia Card (MMC) is a portable flash memory card used in digital cameras, mobile phones, etc.

MultiMedia Cards were developed in 1997 by SanDisk and Siemens based on Toshiba NAND memory, have a seven-pin connector (designed to minimize the risk of contact damage), the card consists of a plastic shell and a printed circuit board on which the memory chip is located, microcontroller and contacts. Despite the serial nature of MMC, data and commands can be transmitted simultaneously. MultiMedia Card works with voltage 2.0V-3.6V, but there are also options with lower power requirements. The SD Card is a nine-pin interface developed jointly by Matsushita, SanDisk and Toshiba in 2000.

There is also a Micro Memory Card (MMC), which is structurally identical to the Multimedia Card, but differs in logical layout and is intended exclusively for use in SIMATIC S7 programmable logic controllers from Siemens AG.

Size 24×32×1.5 mm.

Since 2004, also available in a reduced case 24×18×1.5 mm

end of form start of form With a simple mechanical adapter, RS-MMC cards can be used with equipment designed for "full size" MMCs. Dual Voltage Reduced Size MMC (MMCmobile) are also available, which can operate not only on the standard 3 V supply voltage, but also on 1.8 V.

MMC is mostly compatible with the later developed SD card and can be used instead of SD. In the opposite direction, replacement is most often impossible, since SD cards are thicker than MMC and simply mechanically may not enter the MMC card slot.

MMC uses a relatively simple open data transfer protocol, therefore, unlike Secure Digital (SD), it can be used in homemade devices.

MultiMediaCard, officially abbreviated MMC, is a memory card standard used for solid-state storage. Introduced in 1997 by SanDisk and Siemens AG, GCIs are based on a low pin count serial interface surface contact using a single block memory substrate stack node, and are therefore much smaller than previous systems based on high pin-count parallel interfaces. using traditional surface-mount assemblies such as CompactFlash. Both products were originally introduced using SanDisk NOR based flash technology. MMC about postage stamp size: 24mm×32mm×1.4mm. MMC originally used a 1-bit serial interface but newer versions of the specification allow 4 or 8 bits to be transmitted at a time. MMC can be used in many devices that can use Secure Digital (SD) cards.

Typically, the MMC functions as a storage medium for a portable device, in a form that can be easily removed for access to a computer. For example, a digital camera will use MMC to store image files. Through an MMC reader (usually a small box that connects via USB or some other serial connection, although some may be found integrated into the computer itself), the user can transfer pictures taken with the digital camera to his or her computer . Modern computers Like laptops and desktops, often have SD slots that can optionally read MMC if the operating system drivers can.

KMMs are available in sizes up to 512GB. They are used in almost all environments in which memory cards are used, like cell phones, digital audio players, digital cameras, and PDAs. Since the introduction of SD cards, several companies have been building MMC slots into their devices (with the exception of some mobile devices, such as the Nokia 9300, a communicator in 2004, where the smaller size of the MMC is an advantage), but a slightly thinner, pin-compatible MMC can be used practically any device that can use an SD card if the software/firmware on the device is capable.

While some companies are building MMC slots into the device as of 2018 (SD cards are more common), embedded MMC (EMMC) is still widely used in consumer electronics as the primary means of integrated storage in portable devices. It provides a low-cost flash memory system with an integrated controller that can reside inside an Android or Windows phone or in low-cost PCs and can appear on the host as a boot device, instead of a more expensive form of solid-state storage, such as a traditional solid state drive.

open standard

The best of the four types of MMC cards (clockwise from left to right): MMC, RS-MMC, MMCplus, MMCmobile, metal expander

Below are four cards.

This technology is a standard available to any company wishing to develop products based on it. There are no royalties charged for devices that accept MMC. Membership in the MMC Association must be purchased in order to produce the cards themselves.

As of July 2009, specification version 4.4 (dated March 2009) can be requested from the MMCA, and upon registration by the MMCA, can be downloaded free of charge. Older versions of the standard, as well as some additional enhancements to the standard, such as MiCard and SecureMMC, must be purchased separately.

A very detailed version is available online which contains the necessary information to write an MMC driver.

As of September 23, 2008, the MMCA group has already turned over all the specifications of the JEDEC organization including embedded MMC (electronic MMC) and miCARD assets. JEDEC is a standards organization for the solid state industry.

As of February 2015, the latest version of the 5.1 specification can be requested from JEDEC, and upon registration by JEDEC, can be downloaded free of charge. Older versions of the standard, as well as some additional enhancements to the standard, such as MiCard and SecureMMC, must be purchased separately.

Options

RS-MMC

In 2004 reduced size MultiMediaCard (RS-MMC) was introduced as a smaller form factor MMC, about half the size: 24 mm × 18 mm × 1.4 mm. RS-MMC uses a simple mechanical adapter to extend the card so it can be used in any MMC (or SD) slot. RS-MMS are currently available in sizes up to 2 GB.

The modern continuation of RS-MMC is commonly known as minidrive (MD-MMC). A minidrive is usually a microSD card adapter in an RS-MMC form factor. This allows the user to take advantage of the wider range of modern MMCA available to exceed the historic 2 GB limit of older chip technology.

Version 4.x of the full-sized and reduced-sized cards can be sold as MMC Plus and MMCmobile respectively.

Version 4.x of the card is fully backwards compatible with existing readers, but requires updated hardware/ software to use their new features; 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 must use these features in an SD reader.

MMCmicro

MMCmicro MMC micro size version. With dimensions of 14mm×12mm×1.1mm, even smaller and thinner than RS-MMC. Like MMCmobile, MMCmicro allows dual voltage, is backwards compatible with MMC, and can be used in full size MMC and SD slots with a mechanical adapter. MMCmicro cards have high speed and four-bit bus features of the 4.x specification, but not an eight-bit bus, due to the lack of extra pins.

She was previously known as S-card when introduced by Samsung on December 13, 2004. It was later adapted and introduced in 2005 by the MultiMediaCard Association (MMCA) as the third form factor memory card in MultiMediaCard family.

MMCmicro looks very similar to MicroSD, but the two formats are not physically compatible and have incompatible pinouts.

micard

micard is a backward compatible extension of the MMC standard with a theoretical maximum size of 2048 GB (2 TB) announced on June 2, 2007 the card consists of two detachable parts, the same as microSD cards with SD adapter. The small memory card fits directly into the USB port and also has MMC-compatible electrical contacts, which with the included electromechanical adapter fits into traditional MMC and SD card readers. To date, only one manufacturer (Pretec) has released cards in this format.

Taiwan's development, at the time of the announcement of twelve Taiwanese companies (including ADATA Technology, Asustek, BenQ, Carry Computer Eng. Co., C-One Technology, DBTEL, Power Digital Card Co. and RiCHIP), he signed a contract to manufacture new card memory. However, as of June 2011 none of the listed companies has issued any such cards, and no further announcements have been made about the format's plans.

The card was announced to be available starting in the third quarter of 2007. It was supposed to save 12 Taiwanese companies that planned to manufacture the product and related hardware up to US$40 million in license fees, which presumably would otherwise be paid to owners of competing flash memory formats. The original card was supposed to have a capacity of 8 GB, while the standard would have allowed sizes up to 2048 GB. It was claimed to have a data transfer rate of 480 Mbps (60 MB/s), with plans to increase the bandwidth over time.

SecureMMC

An additional, optional, part of the MMC 4.x specification is a DRM mechanism designed to allow MMC to compete with SD or Memory Stick in this area. Very little information is known about how SecureMMC works or how its DRM characteristics compare to its competitors.

EMMC

The EMMC (embedded MMC) architecture puts an MMC (flash memory plus controller) component in a small ball-packet grid array (BGA) IC for use in printed circuit boards as an embedded non-volatile memory system. EMMC exists in 100, 153, 169 ball packs and is based on an 8-bit parallel interface. This differs markedly from other versions of MMC as it is not a user-removable card, but rather a permanent attachment to a circuit board. In the event of an issue arising from any memory or controller, the entire PCB (Printed Circuit Board) will need to be replaced.

EMMC does not support the SPI bus protocol.

Almost all mobile phones and tablets used this form of flash for primary storage until 2016, in 2016 UFS began to take control of the market. latest version The EMMC standard (JESD84-B51) by JEDEC is version 5.1 released in February 2015 with the speed of competing discrete SATA-on solid state drives (400 MB/s).

other

Seagate, Hitachi and others are in the process of releasing SFF hard drives with an interface called CE-ATA. This interface is electrically and physically compatible with the MMC specification. However, the command structure has been extended to allow the host controller to issue ATA commands to control the hard drive.

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