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[Concept] SD card Secure Digital Card card referred directly translated into Chinese is "Secure Digital Card" Based on a new generation of semiconductor flash memory equipment ======================== [History] 1 August 1999 by Japan's Panasonic, Toshiba, and the United States SanDisk Corporation jointly developed. 2.2001 Most digital camera manufacturers offer a SD card support, including Canon, Nikon, Kodak, Panasonic and Konica Minolta. The SD card is Toshiba added encryption technology hardware made in the MMC card technology. Similar technologies, including Sony's MagicGate. Users can use a USB card reader, SD card in the PC. Some newer computers have built-in card reader device. The latest development is a built-in USB port, SD omitted reader. SanDisk's design is the use of a collapsible sheath to protect the USB socket. Sandisk is not the manufacturer of the first built-in USB SD card. 6. "SD" trademark is actually used for a completely different purpose: It was first used in the "super-density optical disc (Super-Density Optical Disk), developed by Toshiba in DVD format war defeat. This is why the "D" word that looks like a CD-ROM. SD Series Memory Card SanDisk SD Card Association certification specifications sent to complete the test, so almost all patent control in SanDisk hands. 8.2006, SD card capacity of 8, 16, 32, 64, 128, 256, or 512 MB, 1, 2, 4, 6, 8 (SDHC) GB. SD / MMC card has become the most widely used portable digital camera's digital memory card formats. ======================== Principle parameters [Size]: 24mm × 32mm × 2.1mm [Weight]: 2 g [Technology]: a combination of [SanDisk] flash memory card control MLC (Multilevel Cell) technology and Toshiba (Toshiba) 0.16u and 0.13u NAND technology [Number of pins]: 9-pin interfaces connected with the special drive [Power]: no additional power supply to maintain information on the memory [Security]: it is the integration of solid medium, no moving parts, so we do not have to worry about damage to the mechanical movement. ======================== Model miniSD / microSD (in the league did not pass the standard formerly known as TransFlash) / SDHC ======================== [Features] 1 high memory capacity 2 fast data transfer rates 3 great mobile flexibility Good security. ======================== Speed ??grade According to the data transmission speed, SD different levels. The speed rating two representations ------------- ["X" notation] (SD1.0 specification is now not) It is 150kB / s of the CD-ROM for the rate of speed calculation method to calculate. Basically, they can be faster than the transfer speed of the standard CD-ROM 6 times (900 kb / sec), while the speed of the SD card more transmission 66x (10 MB / sec), and a 133x or higher speed. Some digital cameras require high-speed SD card to film more fluid and continuous shooting photos more quickly. In December 2005, most of the equipment follow the SD card 1.01 specification, higher speed to 133x devices also follow 1.1 specification. | Speed ??rating | read speed (MB / sec) | is equivalent to the Speed ??Class | 13 x 2.0 2 26 x 4.0 4 40 x 6.0 6 66 x 10.0 10 ------------- [Speed ??Class notation (for the new version of the SD card and SDHC card) SD2.0 specification speed SD card grading method is: Ordinary card and high-speed card rate is defined as Class2, Class4, Class6 and Class 10 four grades. The rate of ultra-high-speed card UHS Class 1 a level only. The rate level marked symbols on the card as shown below. Different levels of read speed and to be able to meet the application requirements in the table below: | Speed ??rating | read speed (MB / sec) | Applications | Class 0? Including lower than Class 2 and unlabeled Speed ??Class Class 2 2.0 watch ordinary definition television, digital video camera Class 4 4.0 smooth playback of high definition television (HDTV), digital cameras continuous shooting Class 6 6.0 SLR camera continuous shooting, as well as the use of professional equipment Class 10 10.0 Full HD TV recording and playback UHS Class 1 312.0 professional real-time recording Full HD TV ======================== 【Overwrite protection ------------- In the right side of the SD card is usually a switch, that is, overwrite protection switch, MMC card. Overwrite protection switch under SD card will be overwritten protection, data can only be read. When the overwrite protection switch in the above position, will be able to overwrite the data. This protection switch is selective, some brands of SD cards do not have this protection valves. ------------- (2) Principle With cassette tapes, VHS tape, computer disk overwrite protection similar. Off can override turned represents protection. If the switch is damaged, this card can only become read-only memory card write-protected. There is a way to solve this problem, notch sealed with tape, then this card will always be in a writable state. ------------- Kingmax production of SD card write-protect switch. It is produced by the thickness of the SD card and MMC card is the same as 1.4 mm. ========================
【Article is excerpted from: Baidu Encyclopedia】 |
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