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As can be seen from the picture after the transmission of the command frame, it is necessary to continue reading bytes (NCR) from MicroSD before receiving an answer (R1), while the CS level must be active "0".

Depending on the command index, the answer may not only be R1 (see the main command set) on the CMD58 answer R3 (R1 and the final 32-bit value of OCR), and some commands need more time NCR and they will answer R1b.. This is the answer R1, followed by the employment flag (the signal on the "DO" line is held by a low-level card while the internal process continues). The host controller should wait for the end of the process until "DO" does not switch to a high level state (i.e. wait for 0xFF). As well as R2 when requesting status status Status.

The answer R1 contains 1 byte, its structure can be viewed in the table below. The answer R2 consists of two bytes, the first byte R1 and the second R2 (see table structure R2). And the answer is R3, respectively, from 5 bytes.

Answer R1 with 0x00 valuemeans the successful completion of the command, otherwise the corresponding flag will be installed.

Response structure R1.

R2 response structure.

Initialization in SPI mode.

After resetting and pumping the power, the MMC Map is installed in the MMC (Serial Peripheral Interface) mode, to transfer to the SPI mode, you must do the following:

1. After reaching nutrition 2.2 V, wait at least milliseconds, set a high level on the DI and CS lines and give about 80 pulses to the CLK output. After such a procedure, the card will be ready to accept the native command.
2. Send the CMD0 command (software reset). The card must respond (R1) with a set of waiting bits (0x01).
3. Send the CMD1 command (to start card initialization). Wait for the 0x00 response to confirm the completion of the processinitialization.

Let me remind you that the CMD0 command must contain the CRC correct field. It makes no sense to count on, since there are no arguments in this team, it constantly has a value of 0x95. When the card enters the SPI mode, the CRC function will be disabled and will not be checked. The CRC option can be turned on with the CMD59 command.

As a result, the CMD0 command will look like this: 0x40.0x00.0x00.0x00.0x00.0x95.

• team index - 0x40.
• argument - 0x00.0x00.0x00.0x00.
• CRC-0x95.

As for 80 pulses, they can be formed by transmitting by SPI value 0xFF10 times in a row When set high levels on the linesDi and cs.

After idle more than 5 ms, the memory card goes into an energy-saving mode, and can only accept CMD0, CMD1 and CMD58 commands. For this, the initialization process (CMD1) must be repeated almost every time when reading / writing a data block or check the status of the map.

For SDC cards in case of deviation of the commandCMD1 It is recommended to use the ACMD41 command.

The initialization process itself may take relatively long time (depending on the volume of the map) and can reach hundreds of milliseconds.

Reading and writing a block of data.

By default, in SPI mode, the exchange between the microcontroller and the card is carried out by blocks of 512 bytes, by this to record even one byte you will have to first read the entire block and changing the bytes to overwrite it back. The block size can be changed in the CSD register of the memory card.

Waiting for the addressing error when performing read / write commands, it is necessary that the address indicated clearly starts the sector. To do this, you can reset the bit "0" 3 byte of the address of the sector, i.e. Do it even, and the younger should always have a value of 0x00.

Reading data block.

The data block read algorithm is as follows:

• After confirmation of the initialization, we transmit the CMD17 command (answer R1), with the address of the required sector.
• We transmit 0xFF to receiving the start byte 0xfe.
• We accept the data block (by suturing 512 bytes) and 2 CRC bytes.

The CRC value is not necessary, but the adoption procedure (transmission of 0xFF from the MC) is necessary.

Reading block.

Record data block.

The data block record algorithm is as follows:

• If a simple card has been more than 5 ms by sending a CMD1 command (response R1).
• After confirmation of the initialization, we transmit the CMD24 command (answer R1), with the address of the required sector.
• We transmit the start byte 0xfe.
• We transmit the data block (on suturing 512 bytes) and 2 CRC bytes.
• We get byte confirmation recording.
• We are waiting for the end of the record (byte changes 0x00).

The data block may be less than 512 bytes when the block length changes the CMD16 command.

The CRC value is not necessary, but the transfer procedure by any values \u200b\u200bis necessary.

Downtime estimate can be programmatically and not to do, and immediately give the initialization command. The software implementation faced an incorrect entry, for some reason all the bytes were recorded in the Sector with the shift to the left. The problem was solved only by passing the start bit (0xF) twice.

Record block.

Confirmation byte when writing a data block.

Recording / reading multiple blocks in a row.

Using commands CMD18., CMD25 You can read / write several blocks in a row or the so-called multilox read / write. If the number of blocks has not been specified, the read / write process can be stopped by the CMD12 commands when reading, as well as the transmission of the marker " Stop Tran"When recording, respectively.

Practical use.

The practical application of memory cards is quite wide. In the last of its design, MicroSD involved to write indications from various sensors (temperature, alarm) during the day every hour. The data is stored as follows:

• The year is taken by the last two digits - it corresponds to the first (main) byte address of the memory card sector.
• Month, two digits - this corresponds to the second, senior byte address of the memory card sector.
• Day, two digits are multiplied by 2 (in order to avoid outside the border of the sector) - this is the third, middle byte address of the memory card sector.
• Junior, the fourth byte always "0".

As a result, data segments are simplified by date, it is enough just to translate the request to the sector address and read from the card. With this method, the data can be stored for several years. True there are also disadvantages, a lot of unused place remains. Although if desired, you can use for other tasks.

Who needs to throw the code fragment on the assembler for 18 peaks.

Questions can be set on ..

Different memory cards are typical representatives of external storage devices on flash memory. Today, many of the devices in our use, such as: cell phones, cameras, media and MP3 players and others use as a media memory card information.
We believe that it will not be superfluous to know the features that various types of memory cards possess each of which is intended for a specific device.

What inside these cards ...

Flash memory is a kind of data keepers, the main goal in the use of which, increase the functionality of modern mobile devices. This allows manufacturers to lead the market and produce in demand by users. The huge advantage of memory cards is the lack of requirements for additional nutrition, they are satisfied with what is already in the device where they are used. The drive of memory is easily filled with information and is also easily freed from it. It does not have mechanical driving parts, so it requires a minimum of nutrition and its work is practically not limited. Memory cards allow you to rewrite information from tens of thousands of cycles to a million.

The shelf life of data on these devices has enough long and ranges from 20 to 100 years. Another advantage is a small sensitivity to external influences, vibrations and shocks.

But one of the most important advantages of memory cards is their compactness. Having a thickness from three millimeters and less, the card has a maximum length in just four centimeters.

Variety of varieties

In the documentation for your device, there is always a description or abbreviation of the type of memory cards that this device can use. Deciding with the map type, select the manufacturer, focusing on the most famous and already proven manufacturers. Some of these memory cards are equipped with various adapters that significantly increase functionality and allow you to use a memory card in other devices.

To date, there are seven major types of memory cards.
CompactFlash.Otherwise, CF consisting of two types - CF Type I and CF Type II. These varieties of memory cards are most common due to their features that are dramatically distinguished them from other types of compact information media. Having a high data exchange rate and providing a rather high amount of memory These cards possess, together a very low price regarding megabytes / ruble, which is very attractive as for those who produce mobile devices, that for those who use them. For all available data, this is currently the most common type of memory cards.

IBM MicroDrive. - Another kind of memory cards, for which it does not quite suit this definition, format COMPACT FLASH TYPE II Due to the fact that is a practically reduced copy of the winchester. Possessing the cost much lower, other types of memory cards, but is a less reliable device due to moving parts. Another negative feature of this card is higher power consumption. Therefore, rare manufacturers use this species in their products whose connectors correspond to CF Type II.

SmartMedia. - Also is a representative of inexpensive and compact flash cards (thickness of just one millimeter). The low cost of these cards is primarily determined by the use of available components, but this, in turn, is also a disadvantage, since the use of low-cost components can lead to abnormal cases and can cause loss of information.

Multimedia Card (MMC) - Here is perhaps one of the best representatives of the memory cards of this class, the main advantages of this type of memory cards are small dimensions and low power consumption. True, all this has an impact on the rate of information exchange. Dimensions of these cards - 24x32x1.4 mm, and short 24x18x1,4 mm. Use them mainly in cell phones and other devices that have very compact sizes.

SecureDigital (SD) - With their dimensions, these memory cards slightly inferior to MMS, but are more preferable from the speed of the exchange rate when working with a large size of the contained data. This feature dictates and higher prices for them.

MicroSD. - Practically in its characteristics is not inferior to SD, while having smaller sizes. Almost with all the memory cards of this type are included in the SD adapter.

SD and MMC. Back compatible, so MMC memory cards can be installed and operated instead of SD, but inverse ars are not possible. Moreover, in the latest versions of devices manufactured by manufacturers (phones, players) put only the SD type connector to enter the versatility of the card (it is even indicated in the documentation as the SD / MMC connector).

MemoryStick. - Made specifically and is used almost only in devices manufactured by Sony. Dimensions of this memory card - 24 * 32 / 1.4 (2.1) mm., The card is very protected from outside interference, and on its performance it is very similar to a memory card - SecureDigital (SD). However, its weak place is a small amount of stored information.

According to the latest statistics on the most common, generally accepted and used types of types of types CompactFlash. and SD / MMC..

For ease of evaluation of the appearance and dimensions of various types of cards, we will show them clearly:

1 \u003d MMC Plus (Multimedia Card)
2 \u003d SD MINI (Secure Digital)
3 \u003d SD Micro (Secure Digital)
4 \u003d MMC Mobil (Multimedia Card)
5 \u003d MS PRO (Memory Stick Pro)
6 \u003d MS PRO DUO (Memory Stick Pro Duo)
7 \u003d RS MMC (Multimedia Card)
8 \u003d SM (Smart Media)
9 \u003d CF (Compact Flash)
10 \u003d SD (Secure Digital)

What still choose? ...

As a rule, this task is one of the easiest things, you just need to know which type of memory cards can be used in the device you purchased. You can easily learn from the documentation for your device or from the inscriptions on the housing. The only thing you can do is to choose the manufacturer's company based on your preferences.

What volume...?

In general, the question is trivial. You can read by the number of photos, time of music or video, but as a rule, that I would not have chosen always becomes little.

The most important thing is to determine how much you are ready to spend on it, most of the choice decreases at once several times. After all, with a large amount of stored information, high speed of exchange it, minimal dimensions, the price may be too high for the you can afford it. Therefore, just select the most more volume that you can afford.

How to choose a memory card?

It is worth highlighting a number of moments affecting the choice of a memory card:

Memory card volume

It is important to know that the real amount of memory, which has a map, is different from theoretically maximum, which is written on the package. This is due to the fact that the part of the map is the service information: file data, service information, information to protect the memory card from failures, etc. On average, the real amount of memory is 10% less promised.

Speed

Speed \u200b\u200bis a pleasure. The faster the card, the less time it is necessary to write data to the card. A fast map will allow the camera to make more pictures in a short period of time. SUPER, ULTRA, Pro, Xtream memory cards have a higher speed compared to other cards. Per unit of speed is selected. The speed card 133x is twice as fast as the 66x card. Designation 1x means the speed of 150 KB in a second.

Reliability

According to testing data, XD cards and Compact Flash are the most secure. Modern memory cards are designed for several recording cycles, which ensures the safety of data for 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) memory cards often plays a large role for customers. Particularly strong fan moods among young people and photo-lovers. There is a tremendous number of opinions, tests, disputes, about what kind of product card manufacturer is the best! According to the results of some tests - the fastest cards of Kingston's memory, based on the results of other TRANSCEND cards. Someone considers Microdia's most reliable brand, someone SanDisk. As in the case of mobile phones there is no unambiguous opinion on this.

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 are supported by Compact Flash Card. Compact Flash CF Memory Card is ideal for photography lovers. In fact, no map can boast of speeds and volumes as Compact Flash Card. To date, Compact Flash cards have a volume of 2 MB to 128 GB. The most popular "size" Compact Flash 16GB and 32GB. As for speed, then Compact Flash 600x and Compact Flash 667x are currently the fastest card cards. But not only the speed of Compact Flash has become the key to its popularity. Compact Flash Type has one of the most optimal indicators of the volume ratio / price.

As technology develops, this format has evolved. COMPACTFLASH TYPE II (CF Type II) It characterizes the increased read / write speed and a slightly large thickness. Digital technology with a connector for CompactFlash Type II supports and Compact Flash card.

The most famous manufacturers of Compact Flash CF are considered A-Data, ATP, Canon, Fujifilm, Kingston Technology, Kodak, Lexar, Memorex, Olympus, Panasonic, PNY, Ritek, SanDisk, Samsung, Sony, Toshiba, Transcend, Verbatim Corporation, Umax.

MicroDrive. — this is not a completely memory card, but rather a miniature hard drive. CompactFlash MicroDrive has a housing and a connection connector similarCompact Flash II. However, the disadvantages of CF Microdrive are such as increased power consumption and heat dissipation, low speed, sensitivity to vibrations slowly displaces it from the market. Of the advantages, the MicroDrive card has a sufficiently low in the ratio to its amount of the price. The volume of CompactFlash MicroDrive ranges in the range between 170 MB and 8 GB. Map Microdrive 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. File system CF Microdrive - NTFS.

Secure Digital (SD) - This is a joint development of companies Panasonic, Toshiba and SanDisk. At the moment, Secure Digital Card is another of the most disrupted storage formats. The advantages of the Secure Digital card are its small size, high recording and reading speed, low power consumption, the ability to protect information stored on it from copying, accidental erasing or destruction and mechanical strength. The standard SECURE DIGITAL SD card file system is FAT32. The maximum Speed \u200b\u200bSECURE DIGITAL CARD is 300x (i.e., 45,000 kb / s). SECURE DIGITAL memory does not exceed 4 GB.

Expanding the features of Secure Digital Card led to the appearance of additional formats - Secure Digital HC (SDHC) with a maximum volume of 32GB and Secure Digital XC (SDXC) with volume up to 2TB.

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

Minisdhc. (Mini Secure Digital High Capacity) - is an extension of minisd format and allows you to release a memory card with a capacity of 4 GB. However, they are compatible with MINISDHC support devices.

xD-Picture. - Developed in 2001 by well-known manufacturers of digital photographic equipment with Olympus and Fuji companies. From the advantages of the XD-Picture Card, it is possible to name its compactness, reliability, speed, low power consumption. Disadvantages: Together with Sony Memory Stick, this is one of the most expensive memory cards. The XD memory card is found only in the digital cameras Olympus and Fuji In addition, the XD Picture memory is suitable for storing digital films. Compatibility: XD -\u003e Compact Flash (with adapter).

There is an external adapter that allows you to use XD-Picture Card cards in the SMARTMEDIA connector, but it is not fully in the SM slot. There is a limit on the volume of the XD card used (128, sometimes 256 MB), and may also be limitations and in the reading device.

SmartMedia. - Portable flash memory card created by Toshiba, Olympus and Fuji. At the moment, SmartMedia Card has almost completely disappeared from the appeal. Only Japanese digital cameras (for example, Olympus) of past years of release with SMART Media are found very rarely. But Olympus limits the functionality of non-rigging cards, and their purchase will cost much more expensive. A low price and compactness can be attributed to the benefits of the map. The disadvantages are a small amount of built-in memory (SmartMedia card 128 MB - limit), no memory controller for the sake of price reduction, mechanical insecurity and low service life (no more than 5 years). SmartMedia memory card exists in two versions - 5 V and 3.3 V, they differ only on 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 Stick are the most expensive cards on the market, sharing first place with XD. Sony Memory Stick is not even alone, but a whole family of memory cards. It also includes Memory Stick Pro, a speedy option, and Memory Stick Duo is a more compact and expensive card. Memory Stick Pro Duo is used in video cameras, digital cameras, personal computers, printers, PSP gaming prefix and in some SonyEricsson mobile phones.

MEMORY STICK card capacity has never exceeded 128 MB as actually Memory Stick Duo. (also not more than 128MB). More advanced in this matter Memory Stick Pro. (1GB) and Memory Stick Pro Duo (8-16 GB). All of them differ in size, however, there are special adapters to connect the modules of one species in the slot of another species.

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. A little later - in 2008 - MEMORY STICK PRO DUO MARK 2 was published, the volume of which was 16 GB.

Micro Memory Stick. - It 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 sizes) is that the information on it is protected from unauthorized copying.

Multimediacard (MMC)- became the first memory card developed specifically for use in mobile phones and players. MMC appeared in 1997 due to the efforts of SanDisk and Siemens. The first MMC memory cards have been actively promoted by Nokia and Siemens mobile phone manufacturers. The advantages of Multimedia Card are small sizes, as well as durable mechanical design and low power consumption. Among the shortcomings of Multi Media Card can be noted a slow interface, quite high cost. MMC Multimedia Card is mostly compatible with a slightly late SD card designed and can be used instead of SD.

Development Secure Digital Multimedia Card led to the creation REDUCED SIZE - MULTI MEDIA CARD (RS-MMC). The RS-MMC memory card is twice as smaller than the standard MMC card, and its weight is only 1G. To ensure compatibility with the existing MMC standard, when using RS-MMC cards, you need an adapter. In speed, they are similar to the MMC cards, the maximum volume, 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-MMCThis card consumes less energy as a result of the phone will have to be less frequent. It is also worth noting that some Nokia smartphone models support only DV-RS-MMC cards compatibility: RS-MMC \\ DV-RS-MMC -\u003e MMC -\u003e SD (with an adapter).

Memory cards Mmcplus. appeared in 2005, their main difference from SD and MMC cards is a high data transfer rate (up to 52 MB / s). Map MMCPLUS HC. (High Capacity) is an extension of MMCPLUS. The container of this model is 4GB. A distinctive feature of MMCPLUS HC is that it can only be used with compatible devices. And in devices without support, it works as standard MMC.

micrommc. - Designed for mobile devices with ECC support. (Error Checking and Correction - Detection and Fixing Errors when writing / reading). Advantage - low power consumption, thanks to which the cell phone will sit so quickly.

MICARD (Multiple Interface Card) - Multi-interface card developed by Taiwanese Industrial Technology Research Institute, compatible with existing USB ports, as well as MMC card connectors. This is a new type of map, the advantage of which consists in high data transfer rates (480 Mbps). MICARD is used to directly transfer data between the portable device and the desktop without connecting the card reader.

We did not have time to get comfortable with maps corresponding to SD 1.1 specifications (most of the devices still support only a slower SD 1.0), as the transition to SD 2.0 is scored on the horizon. It can be assumed that, as a result, 1.1 becomes a "passing" version, and not worth paying attention to it. In fact, everything is different. There is feelings that the introduction of SD 2.0 will be even slower and painful than the transition from 1.0 to 1.1 or, even with MMC 3.0 by 4.x. Most likely, this process will resemble the transition from the MMC to the SD, which, by the way, did not end as a result - instead of many times predicted (including me) MMC death, this format, on the contrary, has found a second breathing. The reason is the same - no SD and SDHC backward compatibility (such logo will wear all the cards that meet the 2.0 specifications). If the SD 1.1 map can be used together with devices designed for SD 1.0 (albeit at a lower speed - how much it was possible in 1.0), the same applies to MMC 4.x / 3.0, then the SDHC card work in "ordinary" SD device will not. Thus, the SD card 1.1 or MMCPLUS, it was possible to buy for the future, and the SDHC cannot be. At the same time, the SDHC devices will be compatible (when they appear) and with conventional SD cards, so the latter can be quietly acquired. Not the fact that you lose something later. Why? Let's see what SD 2.0 will bring us.

Just work on errors

The transition from SD 1.0 to 1.1 twice the maximum speed of work, the transition from MMC 3.0 to 4.0 gave us, in fact, new cards, and what gives SD 2.0? Officially, only two things - an increase in the maximum amount of cards and Class Speed \u200b\u200bRating. The second is easier, so let's start with it.

As you know, manufacturers prefer to label memory cards at the maximum reading speed, and on theoretically possible. Not everything is not always, but in most cases we see exactly it. Recording speed If it is indicated, then also the maximum, and it is not always, and only in specifications and small font. And the reading speed (notorious "Xers") is most often indicated directly on the map of Arshina (compared to the size of the card itself) letters. However, it is not always at least close to the recording speed (a bright example - MLC chips, where the difference is different in definition), and achieve high values \u200b\u200bof the latter in the case of Flash. Manufacturers do not indicate it - unprofitable. As a result, the purchased "high-speed" card can easily be slower than "ordinary", with which we have more than once. At the same time, in many areas of application, the speed of reading is not very important (think - photos after vacation will be rewritten on a computer in 10 minutes, and not for 5: no one will die), while the recording speed is critical. Example - the same cameras, where low recording speed simply will not allow the serial shooting. Even worse, the case is close to the video record, where the flash gradually becomes one of the frequently used media: the low speed of the recording will make shooting simply impossible due to the fact that most frames will "fall out" with the obvious end result. The first attempt to organize the Bardak with labels was made by the MMC Alliance: MMCPLUS card is not only required to maintain the Specification 4.x, but also have a minimal installed recording speed of at least 2 MB / s. The SD association went even further by entering three classes of cards: Class 2, Class 4 and Class 6. The numbers are not abstract values \u200b\u200bhere, but it is the installed minimum recording speed - 2, 4 and 6 MB / s. The innovation is useful, but not so vital: our tests show that today the overwhelming majority of even inexpensive cards are completely able to cope with a stream of 6 MB / s. On the other hand, it will be easier when buying: for example, if it is known that the SDHC Class 6 is required to fully implement the capabilities of the photo or camcorder, it means that such a card should be signed without swinging the results of testing and descriptions on manufacturers sites. Of course, the possibility of abuse from the manufacturer remains in theory, but in this case it will receive not only sorrowful due to a deceived user in various forums, but also the persecution by the Association, which someone is unlikely to go (even from small companies).

As for the volume, then the situation is simple and understandable. The officially capacity of today's SD cards cannot exceed 2 GB. The restriction is not physical, but a logical: the fault of that used file system - FAT16. The latter also supports volumes of more than 2 GB, but with a non-standard cluster size, for which household equipment manufacturers are mostly not going. And for SDHC, the official file system is FAT32, so the restriction is almost removed. However, some upper frames in the standard have been made - 32 gigabytes, but to such a capacity, the compact cards still grow and grow (and falling and falling :)). In the end, some of the formats support and large volumes, but at least 16 GB cards, not to mention 32 or 64, is not yet visible;) Thus, from this point of view, SDHC is an obvious step forward compared to SD . However, somewhat lubricated the fact that some manufacturers of technology have already mastered the support of FAT32 and within SD 1.1. And the manufacturers of memory cards responded to this by the release of SD cards, a capacity of 4 gigabytes. Such cards even in our territories are already less than 100 dollars. They will work later and in technique with SDHC support (I will remind you that in this direction compatibility is present), and devices that do not support such cards, no one will fix it, because the SDHC will not work in them;)

This is what makes the transition from SD 1.1 to 2.0 unlike transition from 1.0 to 1.1. In the second case, we could simply buy new cards and wait for the emergence of new devices that will allow to reveal all their capabilities. First need first wait for market saturation devices with SDHC support, and later Buy cards, because for old devices they are useless. And even then, you can still use conventional SD large capacity, because they will work in the future. It is possible that in the present, but this is necessary for a specific device to check. So far, on the site SanDisk, I found only seven SDHC compatible devices with all the resulting. It can be said that 4 GB's SDHC Card Actively Announced Recent Time is simply useless - you can buy and ordinary such a container. When I want to get a gigabyte card for eight - another thing: there will be no alternative here. But first you need to purchase a device in which you can use such a map.

And how can this affect the "folk" volumes up to 2 GB? No - SDHC cards of such a capacity are not planned. This market segment will remain a primary SD 1.1, and after all, many users do not need to many users at the current level of prices and two gigabytes. That is why the testing of SD 1.1 cards continues to make sense, and such a situation is able to last for at least one year, and even more. MMC alliance after the appearance of version 4.1 specifications does not produce any sharp movements - first need to master what the standard is already allowed (the best version of the specification has been developed a little later than in the case of a competitor, and there was much more revolutionary than SD 1.1 - in The result is completely standard MMC 4.x cards, with a capacity of 8 GB, already announced, and nothing in the standard did not have to rewor;)). The main interest for us while continue to represent cards compatible with SD 1.1 and MMC 4.1. Such a second time we will study. The topic of today's article is representatives of several Linek Flash cards from Kingston, relating to the two families mentioned. In addition to the manufacturer, they relate them, by the way, also the container is all on gigabyte. For many applications, it is enough, and the price has already dropped to such a level that you can not refuse anything;)

Get acquainted with the subject

According to the chronology of the creation and alphabet, it is more logical to start with MMCPLUS - a direct descendant of those oldest good MMC cards, a tens of ten-other megabytes, from which they started their "pedigree" all branches of the family tree both MMS and SD families. But the rest, in essence, the side shoots, and MMCplus, repeat, straight, although in its content (and a little in the form - the contact group is completely different) significantly different from the ancestor. However, we have seen the cards of this standard, so I will inform that its real capacity according to Everest is 973 megabytes, and move on.

MMC cards were initially developed with a maximum compactness, however, the time has shown that for some applications they are vigilant. The new Escape - Maps RS-MMC, which looked like cropped in the length of MMC, boiled off. Later, DV RS-MMC appeared on their base, differing in support for supply voltage not only 3.3 V, but also 1.8 B, - since energy consumption is directly connected with the voltage, the need to reduce it in mobile devices is obvious. And after the appearance of MMC 4.0 specifications, MmCMobile - DV RS-MMC with support for new operation modes came out. If you look at the other hand, you can call these cards and RS-MMCplus, the benefit and for full-size models is also recommended (even if necessary) voltage support 1.8. First, all RS modifications have noticeably inferior by base capacity (for purely technical reasons. ), however, as technology develops, low-density flash microcircuit prices and user appetite growth (mobile phones, where such cards in the go, have long been competing with digital players for a long time and are closer to the wrath of "digits") a break in case Mass modifications were increasingly reduced. However, I have not yet seen the MMCMobile Announcement on 8 GB, and MMCplus - no problem, but in the retail chain network (at least in Moscow) and those and other cards are still limited to two gigabytes. We, as I said, we test the card with a capacity of 1 GB of claimed or (according to Everest) 988 MB of real.

The Secure Digital standard originated from MMC for a long time ago, and it is not a direct descendant - maps are similar, but, strictly speaking, they are not obliged to be compatible in any direction (however, due to the manufacturers of household equipment, we often can use those and others. It is achieved by using two-storey controllers). It was nominally changed by two versions of specifications (and they existed different times), but, as I wrote at the beginning of the article, version 1.1 will not disappear anywhere in the near future, and from cards up to 2 GB never go anywhere. We test for us just a gigabyte card, and not a simple, but "extreme". However, the speed limit from the point of view of Kingston is at the level of 133x, and some producers have mastered 150x, but the latter in practice can mean anything, and the promised 20 MB / with at least the read-in operations are now quite real. As far as they are real in our case, the tests will show. I will only say that an attempt to achieve technical perfection and create universal cards for all applications played with Secure Digital's bad joke: this same secret is actually no one uses, and it eats the capacitance. According to Everest, a gigabyte SD card from Kingston has a volume of only 941 MB.

The use of flash cards in small-sized technology, as I said, led to the flourishing of their reduced modifications. If the MMC alliance focuses on RS-MMC / MMCMobile, then minisd cards were an alternative to the SD-Association. It is worth noting that the position of the alliance is a little better - in the case of MMS cards are physically and electrically compatible on the connector. The SD Association did not cut, but invented a new form factor 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 for a long time was reduced, but now SD, and minisd was equally overlapped in the standard limitations, that is, 2 gigabytes (in practice, nevertheless, there is a difference - "non-standard" cards twice the greater container in the case of SD exist, and no one did not risk). By the way, the real capacity, which is the funny thing, in our case more at MINISD: 949 MB of Everest :)

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

Testing technique

Testing was performed on the computer next configuration:

• EPOX 8NPA SLI
• AMD Athlon 64 3200+ (512K L2)
• 1 GB RS3200 DDR SDRAM
• system Winchester Western Digital WD740GD
• apacer Megasteno AM230 card
• Windows XP Pro + SP2

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

Competitors

Since our maps have different standards, all that we have previously managed to test on this cardboard will be preserved in diagrams. At the same time, among other things, once again compare each other the possibility of MMC 4. X and SD 1.1: yet, while not so much we tested them to deny yourself the pleasure :)

Reading tests

Repeat the MMCPLUS ultra-speed card record from Apacer in this case, no one succeeds. Kingston MMCplus, judging by the results, supports only four data lines and mandatory (from the point of view of the standard) of the synchronization frequency of 26 MHz. MMCMobile is noticeably faster (most likely, by recycling the entire possible bus width), but does not reach speed SD cards. But the SD, and minisd of the laid cards with the speed of 133x results are quite achieved, despite the fact that no one has declared a record record speed.

Access time for reading for most cards has long been placed in the range of 0.5-1.5 ms. There were no exception and our subjects today. As a funny fungum of fate can be regarded that their results are located alphabetically, despite the alternation of formats in it :)

Record tests

minisd markedly behind the full-sized card, although it works very quickly. SD showed exactly the same result as 133x from Pretec - sometimes it turns out that you can pay attention to the "Xers". In a pair of MMCPLUS / MMCMobile, the positions were changed: judging by the speed, the MLC chips with all the consequences are applied in the second card. And the first reading speed and record do not differ that it works in favor of the theory of narrow the data bus - the flash chips themselves "Zili" would be more, but they do not give them.

Over the only exception, access time on recording operations is, as expected. However, the exception is worthy of a separate mention: access time when recording for SD Ultimate is lower than for the most speed hard drives, although for most flash drives there is an inverse picture (which is visible in the diagram). This result is not unique - quickly "responds" and Flashden Pretec I-Disk Diamond. At such a pace, all flash drives in all parameters of the speed will overturn their magnetic fellows;) still a problem with a limited number of overwriting cycles to decide whether to reduce the price and all - solid drives will play the funeral march to their competitors :)

Real capacity

Above (in the description of the cards), I pointed it, but for ease of comparison, I repeat in the table:

What conclusions can be made? First, it is not necessary to count on the declared capacity - the real is less noticeable. Secondly, even within the framework of the product of one company, one standard may noticeably differ. Third, what I paid attention to, the capacity of MMC cards, with other things being equal higher than that of the SD: nothing is given in this light. The difference between the minimum and maximum in today's testing reaches 47 MB \u200b\u200b- quite recently, cards with a smaller full capacity were a very massive product (the set of cameras is still often smaller invested);)

Prices

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

Mmcplus.	Mmcmobile.	Secure Digital.	minisd.
N / d (0)	N / d (0)	N / d (0)	N / d (0)

TOTAL

Not so long ago, we made sure that MMC cards can be much faster than SD. Today we have already seen the first confirmation of what they are not always faster, even in ideal conditions. In the old equipment, everything will be worse for MMC - speed SDs can lose two times two times, while high-speed MMC can "squeeze" more than an order of magnitude.

As for Kingston's actual cards, they all demonstrate very worthy high-speed indicators, even when it was not promised (when they promised, the reality promises corresponds to). At the same time, they differ in a democratic price that, together with the fame of this brand and a good warranty period, makes them a very reasonable candidate for the purchase. Everything. And which preferences depend on your preferences (or rather, the preferences of your digital technology) in terms of tires and form factors.