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

There are times when the old brain works well with the hands. I've been reading nonstop since January a year ago now in preparation to write the text you've been reading in this book. For the past few months I've been concentrating on some additional 802.11b hardware ideas that I could turn into yet another working variant of the AirDrop series. All of that thinking and reading resulted in a finished piece of 802.11b hardware coupled with a slightly different set of 802.11b firmware routines. As always, my goal along with getting on an 802.11b wireless LAN is to keep it all as simple as possible. So, here we go..

The New Experimental AirDrop Hardware

As you can see in Photo 16.1, I'm sticking with the original TRENDnet TEW-222CF-compatible CompactFlash 802.11b interface and matching up an Xterasys CWB1K NIC with an Atmel ATmega128L. I'll stray from the convention of posting the AirDrop 802.11b driver source lines in the text here as the entire AirDrop 802.11b driver source code library for the experimental AirDrop module is included for your review on the CDROM that accompanies this book. You have already seen 99% of the experimental AirDrop 802.11b driver code in the previous chapters of this book. There are very few modifications and additions to the production AirDrop code in the experimental version.

Photo 16.1: The design in Photo 16.1 is a variant of the production AirDrop-A. The board was lengthened a bit to accommodate the 128K SRAM and its latch.


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Wireless Systems
Wireless systems consist of combined RF components such as transmitters, receivers, transceivers, filters, down / up converters, antennas and antenna positioners.
RAID Controllers
RAID controllers are computer boards that control RAID systems.
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Computer-aided design (CAD) services assist in the computerized design, three-dimensional (3D) modeling, and printing and drafting of engineering components and assemblies.
Rotary Encoders
Rotary encoders convert the angular position of a shaft or axle to an analog or digital code. There are two types of rotary encoders, absolute and incremental encoders, which can be controlled by various technologies which include mechanical, optical, magnetic and fiber optic.
Device Drivers
Device drivers are programs that provide the interface between general use software (such as an operating system) and specific hardware or software modules. With personal computers (PCs), drivers are often packaged as dynamic link library (DLL) files.

Topics of Interest

Yeah, I know. This is supposed to be a book based totally on 802.11b technology. While I was traveling the Internet world in search of the Holy Grail of 802.11b, I came across this rabbit. Nope,...

As you continue reading further into the pages of this book you will find that I have attempted to make everything hardware and everything firmware as simple and straightforward as possible. You will...

The AirDrop-A module is basic AVR ATmega128L microcontroller hardware combined with specialized EDTP Electronics 802.11b hardware and firmware. Logically, the AirDrop-A is a hardware/firmware clone of...

Thus far this 802.11b stuff has been an easy ride and believe it or not, it won't get any more difficult. This chapter will show you what's behind the 802.11b functional building blocks that form the...

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"...