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Embedded Systems September 2000 Vol13_10

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e BREAK POINTS ra1 mg it is so much more effective than getting a replacement. Technology that can't be repaired i a problem. Years ago aid agencies realized that large-scale projects in d1ird world cotmtries often resulted in large scale defects; from this sprang d1e concept of appropriate technology, that which is opti- mized for use in a particular culture. So a series of small, repairable water pumps make more sense d1an a mega-scale water treatment plant in parts of Africa. Mechanical ignitions, which can be ser- viced wid1 bailing wire, replace high-effi- ciency elecu·onic spark systems. There must be some critical size whe re the disposable society we've created "works." One where delivery and disposal are quick and easy. Where the economy is strong enough to support casual replacement. Though it pains me to be part of the dispo able economy, it's the way America works. Technology changes so fast that yesterday's miracle is tomorrow's junk. I once had a Tektronix 545 oscillo- lue. I finally found a teenager who claimed to have a need for it, but fig- ured that soon it, too, would be on the junk heap of outmoded technology. Here in t11e Bahamas I suspect that scope, a 100-pound vacuum tube beast iliat refused to die. The thing must have been 30 years old, worked like a champ, but wasn't fast enough for modern electroni cs. It had to go, but how could I to s such a huge, func- tional thing in the dump ter? Yet in ilie end it was obsolete, a relic with no va. the broken board, or at least makes every attempt to fix the thing. All wiiliout much of a scope, logic ana- lyzer, or development system (he has, in fact, never heard of one). His tools come from Sears. Wire cutters, nee- dle nose pli ers, clunky soldering gear. There's no surface mount ta- tion, not even an anti- tatic mat. Yet he's the master of a microprocessor- based telecom switching station. I peered deeper, trying to under- stand better. The equipment is, by U.S. standards, old but robust. It uses 8085 microprocessors, a mid '70s-era CPU that's still designed into some products. The 8085 is a 40-pin DIP device, an 8-bitter that runs at a few megahertz. Each circuit board is beautifully designed, with wider-than-usual u·acks (perhaps .020), power and ground planes, and two circuit layers on the outside where they're accessibl e. Parts aren't crowded together like com- muters in New York, but spread leisurely around. Each device is a DIP, with pins on 0.1 centers. Many are inserted in high-quali ty machined pin sockets, yielding a somewhat expen- sive but totally reliable connection. If you 're not a hardware person, or are one who came of age in the last decade, the previous paragraph says that parts are accessible, they're replaceable, and pins and connections are large enough that even the bluntest fingers can easily slip a probe on any desired node. The sockets make part substitu- tion hassle-free. More, they allow the engineer to bend pins up and dis- connect them at wi ll to run experi- ments, without soldering. It gives him options, allows him to exercise his ski lls at debugging without requiring a lab full of highly skilled production people . PEG™ does this ... • out of the box • on your hardware • with your tools my old cope would be a p1ize, no doubt to be repaired and maintained for decades to come. Though d1e shop that repairs computers might not fmd it use- ful, it would find it's way naturally through the junk chain to the shop that, perhaps, repairs radios where a lMHz bandwidth is more than enough. Instead of just chucking the thing-because dis- posal itself is so expensive here-this Bahaman system I can't .figure out seems to ensure d1at it'll find it' natural niche in the obsolete technology environment. So the Batelco engineer repairs Portable Embedded GUI RowO Row I ·-· . " " Re~w 2 Rowl Row4 RowS Row& RDW9 Row\0 Row\ \ • II " " " " " www.swellsoftware.com Swell Software, Inc. • info@swellsoftware.com • 810-982-5955 : I Embedded Systems Programming SEPTEMBER 2000 223 • ' fJe

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