From Implementing 802.11 with Microcontrollers: Wireless Networking for Embedded Systems Designers

Overview

The mere fact that a CompactFlash card can be inserted into a PCMCIA adapter sleeve and used as if it were a PCMCIA card implies that the CompactFlash and PCMCIA specifications are almost identical. In fact, the official CompactFlash specification states that CompactFlash cards provide complete PCMCIA-ATA functionality and compatibility including PCMCIA True IDE capability. While we're discussing CompactFlash card specifications, I'll clear up a much-asked question about what voltages CompactFlash cards can tolerate. The CompactFlash specification states that CompactFlash cards can operate with either a +5VDC or +3.3 VDC power supply. The AirDrop modules use the +3.3 VDC power rail. Hmmm The CompactFlash card dual-voltage statement makes me believe that one or all of those unidentified 5-pin SOT-23-5 devices on the 802.11b CompactFlash NICs I "opened up" is a low-dropout voltage regulator. With the exception of the DCF-660W, all of the other 802.11b CompactFlash NIC's have three such devices on their printed circuit board. The DCF-660W has two SOT-23-5 packages and one unpopulated SOT-23-5 site. If we take a look at the PRISM chipset data sheets that we can get our hands on and make the assumption that the newer parts operate in a similar manner, my theory is proven as the ISL3873A's operating voltage range is +2.7 VDC to +3.6 VDC.

We won't be discussing PCMCIA or PCMCIA 802.11b NICs to any great detail within the pages of this book. However, I don't like to talk about things and not show them to you. After all,...

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PCMCIA Networking Cards
PCMCIA networking cards allow a host computer to connect to a network for data transmission and communication.
PCMCIA Bus Interface Cards
PCMCIA bus interface cards translate the data from the PCMCIA bus to another bus, and vice versa. They are used to connect two otherwise incompatible buses.
PCMCIA Modems and PCMCIA Fax Modems
PCMCIA modems and PCMCIA fax modems enable computers to transmit data over telephone lines. They include modem-only devices, modem and fax combinations, and fax/modem products with networking capabilities.
PCMCIA Memory Cards
PCMCIA memory cards and storage cards are used to add memory (RAM, SRAM, Flash, etc.) and/or storage capacity (hard disks, CD-ROM, etc.) to computers.
PCMCIA Cards and Accessories
PCMCIA cards and accessories follow standards developed by the Personal Computer Memory Card International Association (PCMCIA), an international standards body and trade organization. PCMCIA cards, or PC cards as they are commonly known, were designed originally for adding memory to portable computers, but are now used in a variety of devices.

Topics of Interest

Overview All of the source code you're about to encounter was written to help you understand the basic concepts behind writing a microcontroller-based driver for 802.11b CompactFlash NICs containing...

CompactFlash® is a very small removable mass storage PC Card. SanDisk Corporation introduced it in 1994. CF™ cards weigh a half-ounce and are the size of a matchbook, with a thickness that is less...

Thus far, this wireless LAN stuff isn't as hairy as it's been cranked up to be. In the previous chapters we've built some really simple 802.11b hardware and we've taken an extraordinarily "in depth"...

Overview Together we've covered quite a bit of ground to get to this point. However, that 802.11b CompactFlash NIC's Link LED is still flashing telling us that we're still shy of our goal of actively...

December 2001 • Vol.7 Issue 12 Page(s) 92-95 in print issue Add To My Personal Library Upgrading Your Network Interface Card Is Easy & Beneficial Upgrading a NIC (network interface card) for...