Flash Card is a memory that uses Flash Memory technology to store electronic information. It is generally used as a storage medium in digital cameras, handheld computers, MP3 and other small digital products, so it looks compact. , like a card, so it is called a flash card. According to different manufacturers and different applications, flash memory cards include SmartMedia (SM card), Compact Flash (CF card), MultiMediaCard (MMC card), Secure Digital (SD card), Memory Stick (memory stick), and XD-Picture Although flash memory cards such as XD card and MICRODRIVE have different appearances and specifications, the technical principles are the same.
CF card
CF card (Compact Flash) was first launched by SanDisk in 1994. The CF card has PCMCIA-ATA functions and is compatible with it; the CF card weighs only 14g and is about the size of a cardboard match (43mm x 36m x m3.3mm). It is a solid-state product, which means there are no moving parts when working. CF cards use flash memory technology and are a stable storage solution that do not require batteries to maintain the data stored in them. For the data saved, CF cards are more secure and protective than traditional disk drives; they are 5 to 10 times more reliable than traditional disk drives and type III PC cards, and they consume less power. Only 5% of that of a small disk drive. These excellent conditions make most digital cameras choose CF cards as their preferred storage media.
MMC card
MMC (MultiMedia Card) card was launched in 1997 by Siemens and SanDisk, which was the first to promote CF. In January 1998, fourteen companies jointly established the MMC Association (MultiMedia Card Association for short), which now has more than 84 members. MMC's development goals are mainly for digital imaging, music, mobile phones, PDAs, e-books, toys and other products. It is known as the smallest Flash Memory memory card in the world, with a size of only 32mm x 24mm x 1.4mm. Although it is thicker than SmartMedia, the overall volume is smaller than SmartMedia, and it is also lighter than SmartMedia, only 1.5 grams. MMC also puts the storage unit and controller on the card together. The intelligent controller enables MMC to ensure compatibility and flexibility.
SD card
SD card (Secure Digital Memory Card) is a new generation of memory device based on semiconductor flash memory. SD card was jointly developed by Panasonic, Toshiba of Japan and SanDisk of the United States in August 1999. The SD memory card is as big as a postage stamp and weighs only 2 grams, but it has high memory capacity, fast data transfer rate, great mobility and good security.
The SD card combines SanDisk flash memory card control and MLC (Multilevel Cell) technology and Toshiba (Toshiba) 0.16u and 0.13u NAND technology in a volume of 24mm × 32mm × 2.1mm. It passes 9 The pin's interface interface is connected to a dedicated drive and does not require additional power to maintain the information memorized on it. And it is an integrated solid medium without any moving parts, so there is no need to worry about damage from mechanical movement.
SM card
SM (Smart Media) card is a Flash Memory memory card released by Toshiba in November 1995. Samsung purchased the production and sales license in 1996 , these two companies became major SM card manufacturers.
In order to promote SmartMedia to become an industrial standard, the SSFDC Forum was established in April 1996 (SSFDC stands for Solid State Floppy Disk Card. In fact, SmartMedia was called SSFDC at the beginning. It was renamed SmartMedia in June 1996 and became a registered trademark of Toshiba) . The SSFDC forum has more than 150 members, including many large manufacturers, such as Sony, Sharp, JVC, Philips, NEC, SanDisk and other manufacturers. SmartMedia cards are also common micro-storage cards on the market and were once very popular in MP3 players.
Memory Stick
Memory Stick is developed by Sony. Its dimensions are: 50mm x 21.5mm x 2.8mm, and it weighs 4 grams. It has a delicate and eye-catching blue shell (the new MG is white) and has a write-protect switch. Unlike many Flash Memory cards, the Memory Stick specification is non-public and there is no standardization organization. It adopts Sony's own appearance, protocol, physical format and copyright protection technology. To use its specifications, you must negotiate and sign a license with Sony. Memory Stick also includes a controller, using a 10-pin interface, the data bus is serial, the maximum frequency can reach 20MHz, the voltage is 2.7V to 3.6V, and the average current is 45mA. It can be seen that this specification is quite similar to the MMC that appeared at about the same time.
xD card
The full name of XD card is pin interface, it is the smallest memory card currently available. . XD is taken from "Extreme Digital", which means "extreme digital". XD card is a relatively new type of flash memory card. Compared with other flash memory cards, it has many advantages and features. Pocket size: 20mm × 25mm × 1.7mm, with a total volume of only 0.85 cubic centimeters and a weight of about 2 grams. It is currently the lightest and smallest digital flash memory card in the world. Excellent compatibility, with various card readers, it can be easily connected to personal computers. Ultra-large storage capacity, the theoretical maximum capacity of XD card can reach 8GB, which has a lot of room for expansion. XD cards currently on the market have different capacity specifications such as 16MB, 32MB, 64MB, 128MB, and 256MB.