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Papyrus Computer Technologies Ltd.
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Introduction to PCMCIA (PC Card) Technology The Personal Computer Memory Card International Association (PCMCIA) is a standards body and trade association that consists of more than 300 member companies including manufactures of semiconductors, connectors, peripherals and systems, as well as BIOS and software developers and related industries. PCMCIA has developed standards for the personal computer cards (PC Cards). A PC Card is a small form-factor adapter for your personal computer, personal communicator or other electronic device. PC Cards are about the size and shape of a credit card. With the proliferation of the notebook and hand-held computer system, the search for smaller, lighter, and more portable tools for information processing is generating innovative developments in many aspects of the portable computer market. These innovations include display, memory, power management, and overall computer design and size. PC Cards are a key technology for adding memory, storage, and I/O capabilities to portable systems. PCMCIA standards describe the physical requirements, electrical specifications, and software architecture for PC Cards. The PCMCIA Specifications define three physical sizes of cards: Type I, Type II, and Type III. All three types use the same 68 pin edge connector for attachment to the computer, and differ only in thickness. The thickness for Type I, Type II, and Type III are 3.3, 5.0, 10.5 millimeters respectively. A Type I PC Card is typically used for various types of memory enhancements, including RAM, FLASH memory, one-time programmable (OTP) memory, and electronically erasable programmable memory (EEPROM). A Type II PC Card is typically used for memory enhancements and/or for I/O features such as modem, LANs and host communications. A Type III PC Card is twice the thickness of the Type II and is typically used for memory enhancements and/or for I/O features that require a larger size, such as rotating mass storage devices and radio communication devices. Since Type I, Type II, and Type III Cards all use the same interface, the size of the card chosen for the application is dependent on the miniaturization of the technology to be implemented. These PC Cards can be used with laptops, notebooks, palmtops, tablets, and other portable computer systems. PC Cards are convenient alternatives to pocket adapters and docking stations. PC Cards can be used with any personal portable computer system equipped with a PCMCIA slot. The key element of the PCMCIA software architecture are Socket Services and Card Services. Socket Services is a BIOS level software interface that provides a way to access the PCMCIA sockets (slots) of a computer. Socket Services identify how many sockets are in your computer system and detects the insertion or removal of a PC Card while the system is powered on. Socket Services is part of the PCMCIA Specification and interfaces with Card Services. Card Services is a software management interface that allows the allocation of system resources (such as memory and interrupts) automatically, once the Socket Services detects the PC Card has been added. Card Services also releases these resources when the PC Card has been removed. Furthermore, Card Services provides you with an interface to high level software to load any needed hardware drivers. Card Service is also part of the PCMCIA Specification. The combination of PC Card hardware, Card Services software and Socket Services software provides a "plug-and-play" capability in the portable computing environment. What is the throughput of the PC Card interface? Theoretical maximums are as follows: CardBus (32 bit burst mode) 16-bit Memory Transfers (100 ns Minimum cycle) 16-bit I/O Transfers (255 ns Minimum cycle) Please note that actual throughput may be substantially less than the theoretical maximums of the interface. What is the difference between Miniature Card, SmartMedia, Small PC Card, Multimedia Card and Compact Flash? Small Form Factor Card Comparison (all dimensions in millimeters)
* Standard published by PCMCIA What do the release numbers mean? (2.0, 2.1, etc.) The release number refers to the version of the PC Card Standard that a particular card or system was designed to. Basically, release 1.0 supported memory only, and 2.X releases supported both memory and I/O applications. For the most part, release numbers are no longer used at the product level, as consumers were misinterpreting their importance when determining compatibility and interoperability. What affects PC Card compatibility? Card and Socket Services As the primary software specifications of PCMCIA, Card and Socket Services
control the recognition and compatibility of PC Card devices. Recent Improvements The rapid rate of adoption of PC Card slots over the last 4 years has driven
a steady stream of card and host implementations. During that time, PC Cards
containing new technologies were introduced, and significant new capabilities
were added to the Standard. At the same time, considerable experience was gained
by card, host and software vendors, and opportunities to improve compatibility
were recognized. What are CardBus and Zoomed Video? CardBus is the 32-Bit version of PC Card technology. Enabled in the February
1995 release of the PC Card Standard, CardBus allows speeds of up to 133 Mbps at
33MHz. Zoom Video is supported only in WIN98 (Hebrew enabled version) What kinds of devices are available on PC Cards? The PC Card Standard is very flexible, allowing the integration of practically any peripheral device imaginable. Currently Available:
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