Tech Musings Another Patent Horror Story Mid-Range Mensch Computer October, 1995 PCMCIA Plug-In Card Resources

Don Lancaster’s More on magic sinewaves Stepper motor driver chips Tech Musings Another patent horror story Mid-range Mensch computer October, 1995 PCMCIA plug-in card resources

just got yet another letter from journals, shows, and technical pubs, all of the hassles involved is more somebody trying to "protect" and who (c) has thoroughly done all like a gross of forty million. the "idea" they have "invented" their homework, generating (d) full Trying to patent any million dollar I by getting a patent. As is typical production artwork and real working idea is, of course, ludicrously insane. nearly 100 percent of the time, their models currently in an advanced beta In all my many years of running a idea simply was not worth protecting. test of (e) a genuinely and stunningly helpline and developing hundreds of Their product has been available off new product that has a (f) gross sales real-world products, not once have I the shelf from a high profile major potential of at least $12,000,000.00. ever found any individual or smaller supplier for several decades. Actually that twelve mil figure is startup that has genuinely profited Yet they never heard of the leading sorta low. That's only the theoretical from the patent system. company in the field! Nor the trade breakeven. It is based solely on what Yet I have thousands of examples journals involved. Nor did they do an percentage of final profits you are of individuals very badly done in by economic analysis of who would buy going to spend subsidizing attorneys patents. Even murdered by them in their product how. Or check into the and the patent system. The level at heart-attack-during-litigation cases. excessive regulations in their target which a patent may start to overcome Putting my money where my mouth market. They also did not pick up on the fact that lots of potential buyers would prefer a zero cost all-software 3.838 MHz (+5 volt dc source) solution instead. The patent, if issued, could end up internal 9vdc 0.5amp NiCad cells input totally worthless. First, their concept 65C265 Charger & involves a completely obvious safety CPU Regulator lockout device. Forgetting that you could buy one off the shelf, there are volume centuries of prior art involved. Not to mention being completely obvious to Internal speaker any practitioner in the field. Almost Audio certainly, hundreds of other patents Amplifier would encroach on the claims. Headphone jack And it's not in the least clear what purpose their patent would serve once they actually got one. It would 55256 Modem serial I/O in no manner offer any "protection". 32Kx8 RAM Urban lore appears to confuse the Printer serial I/O words "patent" and "product". These two are totally unrelated. 27C256 A patent is a sheet of paper which 32Kx8 ROM Keyboard serial I/O gives you the right to sue someone. Like a stock option, it is worthless Host computer serial I/O unless exercised. A product is the 65C22 useful item that goes out the door and PIA makes a profit for you. Sega game controller I/O Patents have nothing whatsoever 240H x 128V LCD to do with today's successful product output connector 65C22 development! In any way, shape, or PIA form. Most often, they are a totally 4-Meg PCMCIA card slot unneeded sideshow. Guaranteed to cost you time, money, and sanity. 8-Meg PCMCIA card slot At least for most individuals and smaller startups the overwhelming Internal expansion connector majority of the time. Do not even think about a patent unless you're (a) a long term industry insider person who is (b) aggressively Fig. 1 ± INTERNAL ARRANGEMENT of the Mensch Computer. This one is subscribing to all the relevant trade easily customized for a wide variety of mid-range needs.

Copyright c 1996 by Don Lancaster and Synergetics (520) 428-4073 www.tinaja.com All commercial rights and all electronic media rights fully reserved. Reposting is expressly forbidden. 93.1 Tech Musings

but you could easily use the PCMCIA slots for data acquisition, industrial control, or CAD/CAM. An expansion connector is also provided. I/O 1.5 When two pole filtered, Magic Sinewave The Sega is reprogrammable. $0080 700F 81F1 F87F E3FF 0FFE has an So, there's lot of ways to pick up a amplitude of 0.84 and a total harmonic few extra data lines. distortion (3-17) of a mere 0.034%. The black and white LCD display provides a 240 H by 128 V resolution. 1.0 Even when totally unfiltered, the third Which is enough for fairly interesting harmonic distortion is only 0.024% and graphics or 16 lines of 40 characters the fifth ends up pretty much negligible. each. With some sneakiness, you can extend this to 21 lines of 60 smaller 0.5 characters. Or mix the two.

PERCENT DISTORTION One recommended keyboard is the Spacemate by Key Tronic. Full size and 85 keys, but no numeric keypad. 0.0 Any serial comm keyboard or 0.00 0.25 0.50 0.75 1.00 keypad could be used instead. FUNDAMENTAL AMPLITUDE Any old stock 12 volt, 0.5 amp ac supply adaptor provides power. An "adding machine" thermal printer is Fig. 2 ± SOME PRELIMINARY 384-BIT MAGIC SINEWAVES which combine an extra cost option. high efficiency and really low harmonic distortion. No video, color, floppies, or hard is, a free ISMM II if you can find me of KIM-1 and Apple IIGS thrown in. drives. Purposely. any exception. Figure one shows details. The 16-bit CPU is a 65C265, a 6502 For a check list of when patents The computer itself is a sturdy descendant having a 16 meg address and patenting may make sense, look 1-1/2 by 7-1/2 by 10 inch block. Three space having exceptionally powerful at WHEN2PAT.PDF you will find on pounds worth. Most of the weight is addressing modes. Also internal to www.tinaja.com For lots of working from the rechargible battery. There's the computer is 32K of EPROM and and proven real world alternatives, four telephone-style serial ports. For 32K of system RAM. Up to 12 megs pick up my Case Against Patents. keyboard, printer, modem, and a host of additional memory can be picked PC programming link. up in the PCMCIA slots. The Mensch Computer Two PCMCIA card slots might get The rest of the internal circuit is What do you use when the BASIC used for additional memory, as data mostly two parallel interface chips. Stamp is too wimpy and a laptop PC recorders, for floppy disk substitutes, Plus the usual "glue" items such as a is clearly gross overkill? There's lots modems, or even a GPS receiver. speaker amplifier, charger, regulator, of emerging uses for a no-nonsense A game paddle port for the Sega and a low batt detector. and easily customized experimenter's compatible six-button arcade pad. An Battery use is optional. There's an mid-range computer. Especially one internal speaker, volume control, and automatic recharge every time you that can be battery powered. headphone jack. A 20-pin connector plug the Mensch into the wall. Enter that new Mensch Computer for the removable stand-alone LCD The micropower CPU firmware has from Western Design Center. Sort of text and graphics display. several battery saving modes. Battery a reincarnated AIM-65 with touches There are no parallel ports as such, life is mostly set by the display activity and the peripherals. Development work is easiest done 1. Pick the number of bits per word. 384 is often a good choice. using assembly tools already in place for the Apple IIGS. Development by 2. Pick an amplitude n based on the number of ones per word. cross-porting from a PC is possible. 3. Pick a desired number of efficiency-setting transitions. Fairly extensive subroutine libraries 4. Calculate the number of clumps k. This is one-half the number are built into the firmware. of transitions for even solutions. The quantity pricing for the Mench 5. Generate a list of all possible sums of k integers that total n. computer by itself is well under $200. The computer lists for $365. Or $895 6. For each entry on the list, fit it to a n(1-sine) function. Then select the one with the lowest classic Fourier series distortion. including display and keyboard. Western Design Center has a very 7. Optionally "anneal" the final clumps by jittering their positions. aggressive developer program. They 8. Compile and plot the results. definitely welcome your designs and suggestions. Free literature packages are available. Fig. 3 ± THE ALGORITHM that I'm now using to find magic sinewaves. Be sure to give them a call.

93.2 Copyright c 1996 by Don Lancaster and Synergetics (520) 428-4073 www.tinaja.com All commercial rights and all electronic media rights fully reserved. Reposting is expressly forbidden. October, 1995

frequency and amplitude. Along with its sequence up in a table and shove This Month's Contest harmonics that are either zero or of it out a port. The frequency can be I am not sure exactly what I'll be tightly controlled low values. separately set by picking a suitable doing with my Mench computer just Compared against traditional PWM dwell time between output bits. Most yet. Improving my helpline data base pulse width modulation, these magic of the job is easily done by a dollar (now mostly a humongous notebook), sinewaves can be far more efficient, PIC or other low-end micro. serving my Synergetics Consultant's can allow much less heatsinking, use The magic sinewaves are brand Network service, finding new magic cheaper parts, produce far less high new because the good ones have been sinewaves, and designing CAD/CAM frequency energy, can provide much so excruciatingly hard to find. Things flutterwumpers come to mind. cleaner waveforms, and end up vastly do not begin to get interesting until The beauty of this system is the more "microcontroller friendly". you get up into the 200+ bit range. ease with which it can become most To use a magic sinewave, you look And there's a lot of possible 200 bit anything from a game to an email terminal to a data acquisition system to a survey instrument to a personal organizer to a special calculator. phase B Key Western Design watchwords are user empowerment. But why don't you tell me instead? 12mH, 12 Ω 12Volt, 0.95Amp, phase A For this month's contest, just tell me STEPPER MOTOR what you would use a Mench for. As usual, there will be a dozen or more Incredible Secret Money Machine II book prizes going out to the better PGND entries. Plus the all-expense-paid (FOB Thatcher, AZ) tinaja quest for LMD18245 two going to the best of all. In addition, I will pass along the more interesting entries to the design 1 OUT1 2 CP OUT 3 RC 4 M4 5 PGND 6 M3 7 M2 8 M1 9 VCC 10 BRAKE 11 DIR 12 SGND 13 CS OUT 14 DAC REF 15 OUT2 engineering team at Western Design Center. At their discretion, they may or may not award Mench computers nc amplitude "8" and development systems to several amplitude "4" of the more promising entrants. +5V amplitude "2" Send your written entries directly +40V to me here at Synergetics, and not to amplitude "1" PHASE "A"

INTERFACE brake control Western Design Center or Electronics + + direction control Now editorial. Let's hear from you. MICROCONTROLLER

More Magic Sinewaves 20K 2.2nF 1.0 µF 100 µF 500pF 20K I've been doing a lot more with the magic sinewaves we looked at a few PGND columns back. There are several very exciting new opportunities here. LMD18245 Megabuck ones even. Your key secret to induction motor speed controls, auto electronics, solar 1 OUT1 2 CP OUT 3 RC 4 M4 5 PGND 6 M3 7 M2 8 M1 9 VCC 10 BRAKE 11 DIR 12 SGND 13 CS OUT 14 DAC REF 15 OUT2 energy interface, power conservation, uninterruptible line conditioning, and nc related power electronics is just this: amplitude "8" Come up with a cheap and efficient amplitude "4" +5V source for variable voltage, variable amplitude "2" +40V frequency power sinewaves. amplitude "1"

All done by suitably flipping some PHASE "B" INTERFACE brake control ordinary "H-bridge" switches from a + + direction control fixed direct current supply. MICROCONTROLLER

Preferably flipping only one-half 20K 2.2nF 1.0 µF 100 µF 500pF 20K of the bridge at any time. A magic sinewave is a repeating long serial string of ones and zeros. Fig. 4 ± A HIGH PERFORMANCE stepper motor driver. Component values Picked to give a variable fundamental must be closely matched to the stepper.

multiple of 96. First, you'd like each PCMCIA MEMORY CARD RESOURCES of your four sine quadrants to end up identical. Especially if you are going to fit lots of amplitudes into a tiny AMP Omega Micro address space. Second, you'd like a PO Box 3608 440 Oakmead Parkway multiple of three for any three phase Harrisburg PA 17105 Sunnyvale CA 94086 (800) 522-6752 (408) 992-1100 power applications. And third, you'd sure like all three Anabooks Panasonic IC Memory Cards 11848 Bernardo Center Dr #110 1 Panasonic Way of those phases to be working on the San Diego CA 92128 Secaucus NJ 07094 same bit position in an 8-bit word at (800) 462-1042 (201) 348-7000 any given time. Otherwise your code Focus Microsystems PCMCIA Association will get too hairy. 3 times 4 times 8 1735 N First Street Ste 307 2635 North First Street Ste 209 gives you 96. This also easily handles San Jose CA 95112 San Jose CA 95134 single-phase systems. (408) 436-2336 (408) 433-2273 The solutions for 96 and 192 don't Globe Robinson Nugent give enough amplitudes and require 1159 US route 22 PO Box 1208 Mountainside NJ 07092 New Albany IN 47151 high distortions. 288 is marginal for (800) 227-3258 (812) 945-0211 low end apps. And values above 384 GPS World Sparky Solutions might raise the system clock rates. Or 859 Willamette St 13534 Myren Drive limit frequency choices. Eugene OR 97440 Saratoga CA 95070 Through a disgustingly sneaky half (503) 343-1200 (408) 867-8540 bit offset trick, you could make each Greystone Peripherals Surface Mount Technology one in your 384-bit word count twice. 130-A Knowles Drive 17730 W Peterson Rd Giving you a seven bit or 128 level Los Gatos CA 95030 Libertyville IL 60048 low jitter amplitude resolution. From (408) 866-4739 (312) 362-8711 0 to 100 percent of supply power. In Hyundai Swart Interconnect more or less uniform steps. 510 Cottonwood Drive 340 Roebling Road Milpitas CA 95035 South San Francisco CA 94080 Figure two shows us the distortion (408) 232-8000 (415) 588-8651 levels for one collection of 384 bit by IC Card Systems & Design Sycard Technology 16 transition magic sinewaves. And 6151 Powers Ferry Road NW 1180-F Miraloma Way optimized both for low distortion and Atlanta GA 30339 Sunnyvale CA 94086 for best efficiency. Note that filtered (404) 955-2500 (408) 749-0130 total harmonic distortions average 0.1 Mobile Media TDK percent or less! 1977 O'Toole Avenue Ste B207 136 New Mohawk Road One really useful 384 bitter has a San Jose CA 95131 Nevada City CA 95959 (408) 428-0310 (916) 478-8421 quadrant of hex 0080 700F 81F1 F87F E3FF 0FFE. Using a two pole filter, the total distortion for harmonics 3 numbers to thoroughly explore. get, the jitter, the harmonic distortion through 17 is a mere 0.034%. Even Great heaping bunches, even. (with and without filtering), and how with no filtering, the third harmonic Let us see. We started off here a many efficiency-robbing transitions is way on down at 0.025% and the few columns ago with a listing of 210 are needed. Optimizing everything at fifth is utterly negligible. bit magic sinewaves that had zero once gets real tricky in a hurry. Only 15 or 16 single switch events harmonics 2 through 10. I expanded I'm now working with "minimum are needed per quarter cycle. A PWM on this with several 420 bit solutions harmonic energy" synthesis on 384 circuit might need up to 192 double which I published in the June 1995 bit words. There's some compelling switching events. For twenty five Circuit Cellar and in MAGICSIN.PDF reasons to use a bit length that is a times the switching losses. on my www.tinaja.com . Once you start synthesizing long Meanwhile, a math genius by the magic sinewaves, there are all sorts name of Jim Fitzsimons suggested a NEED HELP? of heplful games you can play. By "minimum harmonic energy" scheme. Phone or write all your US Tech predistorting you can force certain Where you make each bit contribute Musings questions to: problem harmonics to zero. Possibly as much of its energy as possible to shifting energy higher in frequency Don Lancaster the fundamental. Synergetics where it is more easily filtered. You Which leaves all bits with neither Box 809-EN can also anneal in which you jitter the energy nor much inclination to Thatcher, AZ, 85552 the bits around a little and see if any generate lots of strong harmonics. (520) 428-4073 of the results get better. Annealing While all odd harmonics are present, can significantly assist most of the US email: [email protected] these are often amazingly weak. Web page: www.tinaja.com low amplitude magic sinewaves. Any magic sinewave trades off its And by clumping, you can reduce length against the amplitudes you can all the transitions without hurting the

93.4 Copyright c 1996 by Don Lancaster and Synergetics (520) 428-4073 www.tinaja.com All commercial rights and all electronic media rights fully reserved. Reposting is expressly forbidden. October, 1995 distortion all that much. A clumping can be based on an intelligent prebias NAMES AND NUMBERS that encourages a one if you have a previous one, and vice versa. But a newer and better approach to Central Semiconductor National Semiconductor clumping is to simply list all possible 145 Adams Avenue 2900 Semiconductor Road Hauppauge NY 11788 Santa Clara CA 95052 integer clump combinations that sum (516) 435-1110 (800) 272-9959 to the desired amplitude. Then pick Scott Edwards Ozen Sound Devices the best one. See SUMINTS.PS for 964 Cactus Wren Lane 225 Broadway some working code. Sierra Vista, AZ, 85365 New York NY 10007 Figure three shows the algorithm (520) 459-4802 (212) 962-3232 I'm currently using to discover good GEnie PAIA Electronics magic sinewaves. So far, it gives you 401 North Washington Street 3200 Teakwood Lane good results. But not yet the best. Rockville MD 20850 Edmond OK 73013 Some filtering is often needed with (800) 638-9636 (405) 340-6300 any magic sinewave. Typically, your Hitachi SGS Thompson motor inductance can give you the 2000 Sierra Point Pkwy 1000 East Bell Road Brisbane CA 94005 Phoenix AZ 85022 first pole for your filter. Results are (415) 589-8300 (602) 867-6259 dramatically improved if you can use a two pole lowpass filter that drops Key Tronic Surplus Traders PO Box 14687 PO Box 276 off at -12 decibels per octave. And Spokane WA 99214 Alburg VT 05440 cutting off at the second harmonic. (509) 928-8000 (514) 739-9328 Even unfiltered harmonic energy Micrel Semiconductor Synergetics could get reduced with longer magic 1849 Fortune Drive Box 809 sinewaves. Or by permitting extra San Jose CA 95131 Thatcher AZ 85552 transitions per cycle. (408) 944-0800 (520) 428-4073 What does all this mean for you? Ming Engineering Temic There is now a brand new "magic" 17921 Rowland Street PO Box 54951 way to produce power sinewaves that City of Industry CA 91748 Santa Clara CA 95056 looks like a very promising route to (818) 912-9469 (408) 970-5700 solve some rather sticky problems. Motorola Western Design Center Judging by what's happened so far, 5005 East McDowell Road 2166 East Brown Road Phoenix AZ 85008 Mesa AZ 85203 there are even more exciting magic (800) 521-6274 (602) 962-4545 sinewaves waiting in the wings. All that is needed is the time, effort, and funding to isolate them. figure three are in MS384X16.TXT the LMC6001 and LMC6462 op amps. My preferred tool for this leading and SINTOOLS.PS. The usual way you pick these edge work is that incredibly superb By the way, magic sinewaves can freebies up is with the postcards in general purpose PostScript computer sometimes be used to eliminate the E.E. Times, EDN, Electronic Design, langauge. Helped along, of course, capacitor in certain two-phase motors and similar trade journals. Much by my good old Apple IIe. such as those used in air conditioning more on this in my Resource Bin and PostScript handles 384 bit words blowers. But on the other hand, you Blatant Opportunist reprints. with aplomb. You simply put them should avoid using magic sinewaves Their LMD18245 stepper motor into strings and then manipulate the with any capacitor or other high pass drive chip is interesting. Figure four strings. It takes around a thirtieth of a filtering device. shows us additional details on this 3 second to find all the harmonics of I have now got some brand new ampere, 55 volt device. any magic sinewave. ready-to-run hardware. Including a There are several problems when In fact, we're sort of having a race. three phase system in less than 200 driving a stepper motor. The first is Jim is using absolute mathematical machine language instruction bytes! efficiently sensing the motor winding rigor on a gonzo supercomputer. And And lots of source code that can be current. National uses the "lossless" I'm intuitively "shaking the box" to made available. On a consulting or a scheme in which they parallel 4000 or see what falls out of an Apple IIe. As codeveloper basis. so identical output transistors and of last night, the Apple was at least Give me a call if you want to tap then sense the current through only temporarily in the lead. this big bucks opportunity. one of them. Giving a scale factor of Much more on all of this is on the a quarter mil per amp. magic sinewaves library shelf of my A New Stepper Driver The second is to use current drive. www.tinaja.com You will find dozens National Semiconductor has been When you attempt voltage driving a of the latest files here. Including a generous with free samples lately. stepper, you'll get into time constant new MSINPROP.PDF development Embarrasingly so, even. Especially problems that very much limit speed proposal. All of those actual magic their LM45 temperature sensor, the and power. Using current drive, you sinewaves using the algorithm from ADC16071 Sigma-Delta converter, or apply your full supply voltage to the

new from stepper winding. With zero current source for texts on cards and flash DON LANCASTER limiting resistance. memory is Anabooks. That inductance of your stepper The leading industry trade journal ACTIVE FILTER COOKBOOK winding should cause your current to is IC Card Systems & Design. The The sixteenth (!) printing of Don’s bible on analog ∆ ∆ op-amp lowpass, bandpass, and highpass active ramp up at the usual i/ t = e/L rate. other names on our list are mostly filters. De-mystified instant designs. $28.50 When you reach the desired current suppliers of support hardware and level, you'll quickly turn your drive test systems. Plus various cards. CMOS AND TTL COOKBOOKS power off. You repeat this process Let me know if you want to get Millions of copies in print worldwide. THE two books for digital integrated circuit fundamentals. many times per stepper phase. into more details on all the pinouts, About as hands-on as you can get. $28.50 each. A third problem is that you will timing, and similar specs. usually want higher currents when INCREDIBLE SECRET New Tech Lit MONEY MACHINE II you are stepping than when you are Updated 2nd edition of Don’s classic on setting holding. National handles this with From Hitachi a pair of new data up your own technical or craft venture. $18.50 an on board four-bit D/A converter. books on Wireless Communications Which lets you set your stepper drive and Optoelectronics. Through Micrel LANCASTER CLASSICS LIBRARY current to sixteen possible levels. Semiconductor, a new data book on Don’s best early stuff at a bargain price. Includes the CMOS Cookbook, The TTL Cookbook, Active Including zero. Analog Power Integrated Circuits. Filter Cookbook, PostScript video, Case Against Patents, Incredible Secret Money Machine II, and As with any coil, you'll never want From Temic, a catalog on RF IC's for Hardware Hacker II reprints. $119.50 to suddenly stop the current. Doing Wireless Applications. Temic is a so will generate destructive voltage renamed Telefunken. A data book on LOTS OF OTHER GOODIES spikes. Problem four involves safely surface mounted transistors and such .Ask . . . the. . . Guru. . . . .I . or. . II. .or . . III...... $24.50...... Hardware ...... Hacker...... II, . .III . .or . .IV ...... $24.50. . . . . shutting down the drive. To do this is offered by Central. .Micro . . . . .Cookbook ...... I...... $19.50...... PostScript ...... Beginner ...... Stuff...... $29.50. . . . . there is a brake input that effectively A Power Factor Correction guide .PostScript ...... Show . . . . .and . . . Tell...... $29.50...... Intro . . . .to . .PostScript ...... Video ...... $29.50. . . . . shorts the stepper winding, letting the is offered by SGS-Thomson. Speech .PostScript ...... Reference ...... II ...... $34.50. . . . . current safely decay to zero. modules suitable for toys and other .PostScript ...... Tutorial/Cookbook ...... $22.50...... PostScript ...... by . . Example...... $32.50. . . . . A separate direction input lets you low end applications are offered both .Understanding ...... PS. . . Programming...... $29.50...... PostScript: ...... A. .Visual . . . . . Approach...... $22.50. . . . . decide which end of the H bridge gets from Ozen Sound Devices and Ming .PostScript ...... Program ...... Design...... $24.50...... Thinking ...... in. . PostScript...... $22.50. . . . . positive supply current. Engineering. Ming also has its new .LaserWriter ...... Reference ...... $19.50...... Type . . . . 1. .Font . . . .Format ...... $16.50. . . . . The wide TO-220 package includes Electronic Products Catalog having .Acrobat ...... Reference...... $24.50. . . . . power drivers. Some heat sinking is some great breadboarding stuff in it. .Whole . . . . . works...... (all . . .PostScript) ...... $380.00...... Synergetics ...... Surplus ...... Catalog ...... FREE . . . . required. A pair of chips are needed Wall adaptors at ultra low costs in .Technical ...... Insider ...... Secrets...... FREE . . . . for two-phase stepper motor use as infinite variety are available by the POSTSCRIPT SECRETS shown. This chip and others in the zillions at Surplus Traders. A Book/Disk combination crammed full of free family may also be used in DC motor PAIA Electronics has a brand new fonts, insider resources, utilities, publications, workarounds, fontgrabbing, more. For most any drives. External MOS transistors can Theremin kit. PostScript printer. Mac or PC format. $29.50 be added for higher voltages. Motorola has a free sample pack A PIC chip is ideal to control the including dozens of their new BRT BOOK-ON-DEMAND PUB KIT Ongoing details on Book-on-demand publishing, LMD18245. Suitable interfaces are Bias Resistor Transistors. These are a new method of producing books only when and offered by Scott Edwards Electronics your choice of a NPN or a PNP along as ordered. Reprints, sources, samples. $39.50 with his Pseudo Stamp. with a pair of integrated resistors. THE CASE AGAINST PATENTS Yes, the new magic sinewaves will Mostly for "RTL" glue logic, LED For most individuals, patents are virtually certain interface beautifully to several chips drivers, and such. to result in a net loss of sanity, energy, time, and money. This reprint set shows you Don’s tested in this series for ac motor drive apps. For the fundamentals of digital and proven real-world alternatives. 28.50 integrated circuits, check into my PCMCIA Card Resources TTL CMOS BLATANT OPPORTUNIST I Cookbook or Cookbook. The reprints from all Don’s Midnight Engineering I've been getting quite a few calls Either by themselves or as part of my columns. Includes a broad range of real world, proven coverage on small scale technical startup on the "memory cards". Credit card Lancaster Classics Library. See my ventures. Stuff you can use right now. $24.50 plug-ins which first started life as nearby Synergetics ad for details. laptop memory inserts. But they now As is usual, instant help answers, RESOURCE BIN I A complete collection of all Don’s Nuts & Volts include modems, MIDI drivers, data preprints and reprints of most of my columns to date, including a new index and his acquisition systems, new CAD/CAM stories and all referenced files are master names and numbers list. $24.50 driver interface, Ethernet comm, and available on www.tinaja.com FREE SAMPLES even GPS receivers. So I guess we're You'll also find our consultant's Check Don’s Guru’s Lair at http://www.tinaja.com due for a resource sidebar. network and scads of annotated hot for interactive catalogs and online samples of Don’s unique products. Searchable reprints and These are correctly called PCMCIA links here. Come visit. reference resouces, too. Tech help, hot links to cool sites, consultants. email: [email protected] cards. Short for Personal Computer Most of the mentioned resources FREE US VOICE HELPLINE VISA/MC Memory Card Interface Association. will show up either in the Names & SYNERGETICS The best starting point is the PCMCIA Numbers or PCMCIA Memory Card Box 809-NV Developer's Guide. A book and disk sidebars. Be sure to check here first Thatcher, AZ 85552 combination available from Sycard before calling our tech helpline. (520) 428-4073 Technology at $90 list. One second Let's hear from you. ✦

93.6 Copyright c 1996 by Don Lancaster and Synergetics (520) 428-4073 www.tinaja.com All commercial rights and all electronic media rights fully reserved. Reposting is expressly forbidden.