PCMCIA(PERSONAL COMPUTER MEMORY CARD INTERNATIONAL ASSOCIATION)

PCMCIA is" PERSONAL COMPUTER MEMORY CARD INTERNATIONAL ASSOCIATION" the abbreviation, PCMCIA defines three different types of cards, it is PCMCIA ( PC computer memory card International Association abbreviation) is a has more than 300 members of the company's international standard organization and Trade Association, the organization was established in 1989, is to establish the integrated circuit international standards, improving the interchangeability of mobile computer. This computer with high strength, low energy consumption, small size, but also on the several performance requirements are very high. Because the movable computer user needs change, so the PC card standard corresponding to the change. In 1991, PCMCIA defined originally used in the memory card 68 feet I / O connection standard. While increasing the slot for use. Manufacturers recognize software needs to improve compatibility, so this standard will be a corresponding application.

Development process

In recent years, the application of PCMCIA to realize high speed increases demand, such as multimedia and high-speed network. Therefore, to establish the CardBus and Zoomed Video specification, the specification allows MPEG video and 10 Mbit Ethernet at high speed operation. Because the speed of increasing, PCMCIA also has been added the code, so as to improve the compatibility and considering some other removable machine problems, such as the 3.3V operation and power management.

Today, PCMCIA has not only promoted the mobile computer PC card 's ability to work together, but also improve the many other product 's ability to work together, such as digital cameras, cable TV, set-top boxes and car. Due to the demand for the modular peripheral equipment products increased, and many peripherals compatibility is improved. Therefore, PCMCIA has recently changed its mission:" the development of modular peripheral standard, promote all over the world application."

PCMCIA new tasks are typically small structure card standard. PCMCIA in the original PC card standard on the basis of an increase of PC machine small structure card standard, now PCMCIA has issued and maintained at the application of the micro card standard. In addition, PCMCIA will release a smart media card standard, the standard has the minimal module external set provides the memory structure solution.

PCMCIA defines three different types of cards, their length and width is 85.6 x 54mm, but differ in thickness. Type I is the earliest PC card, thick 3.3mm is mainly used for RAM and ROM; Type II thickness 5.5mm range also extends substantially comprises a majority of the modem ( modem ) and faxmodem ( fax modem ), LAN adapter and other electrical equipment; Type III further increasing the thickness to 10.5mm the PC card is mainly used for rotary storage device ( such as a hard disk ).

Classification

PCMCIA bus is divided into two categories, one category for 16 PCMCIA, another kind is the 32 bit CardBus.

CardBus is one used for a notebook computer new high performance PC card bus interface standard, is widely used in desktop computer PCI bus. The bus standard and the original PC card standard, has the following advantages: first, 32 bit data transmission and 33MHz operation. CardBus Fast Ethernet PC card maximum throughput is close to 90 Mbps, and 16 Fast Ethernet PC card can only reach 20-30 Mbps. In second, bus independent. The PC card can separate from the main CPU, and computer memory exchange data directly, so CPU can deal with other tasks. In third, 3.3V power supply, low power. Improved battery life, reduces the internal computer thermal diffusion, enhanced system's reliability. Fourth, backward compatible 16 PC card. Vintage Ethernet and Modem equipment PC card still can be inserted in the CardBus slot on the use of.

High version of the PCMCIA card interface can generally be well compatible with the version of the card. That is to say a Type I slot can only insert a Type I card; a Type II slot to insert a Type II card or a Type I card; a TypeIII slot in addition to insert a Type III card can also be used for inserting two compatible with Type I or Type II card.