Slashdot Mirror

It's a very effective "annoyer" or "hassler", but it's not effective in the face of moderate effort to overcome it.

To expand: National Semiconductor has Webench (which I've worked on to some extent) and it allows you to set up a schematic, runs simulations, produces a bill of materials for you, produces a layout, produces gerbers, shows you which parts are in stock and how much they cost, and will even fab the boards and send you a bag of parts to put on your boards. That's really amazingly useful... as long as you want to use a National Semiconductor part. Not so great if you want to do something new or build a complex circuit outside of their limited repertoire.
If these guys could do even a subset of that -- note I don't expect automated layout, because that's not within AI's reach, yet -- but produce a BOM with links to Digikey and Newark so I could check parts in stock/datasheets/verify footprints, and most critically produce a netlist so *I* can do the layout, well, then, that'd be very convenient indeed. But if I'm pretty much stuck with their partslist and admiring my schematic as it sits trapped in their garden, that's still cool (and it's a neat tool to use) but I'm going to end up re-entering the schematic in something that has a layout backend and most likely a simulator and library editing functionality, and at that point I don't get much from this aside from the convenience of being able to enter schematics when I'm hanging out at an internet cafe or something.

A classic tecnology updated!

http://www.national.com/rap/files/datasheet.pdf

hmm, the wiki actually is light on info about mr. pease.

here's a better link: http://www.national.com/en/corporate/remembering_bob_pease.html

tl;dr: he designed the lm331 (volt to freq converter) and lm337 (negative compliment to the famous lm317 voltage regulator chip). and many other things.

For security, no one is allowed to see the captured imagery. You can digitize and store at as high of a resolution as you like, limited only by how much memory you allocate. Special memory is needed.

http://www.national.com/rap/files/datasheet.pdf

Very, very sad news. I have been to a few of his lectures and can say that this man was an original. He presented with an overhead projector (the analog presentation method). I don't know what it is about the analog gurus, they seem to live a mildly tortured life. Bob Pease is my favorite, second only to Bob Widlar. That guys stories are so far out there. Pease did a writeup of some of his most memorable stuff... makes me wish I were there when it happened. I can only say that I am glad I met Pease in his time here on Earth... RIP my friend. http://www.national.com/rap/Story/widlar.html

The core component of the seatbelt reminder system:

http://www.national.com/rap/files/datasheet.pdf

Reminds me of the old joke "write only memory." Pretty funny for the hardware types.

Datasheet available HERE..

On a side note, I do now know if this link will be available long-term since TI purchased National Semi.

The oscillators in the circuits to power LEDs, are typically part of a switching power supply, that runs at 100s of kiloHertz. The PWM dimming CAN be run slowly, but that is considered poor practice. The LEDs can easily be switched at tens of kiloHertz. The controller I ran across for "dimmable LEDs on a Triac circuit" (most home dimmers) http://www.national.com/pf/LM/LM3445.html points out that it has no 120Hz flicker; they PWM much faster than that.

I am almost certain that if/when you see flicker in a LED string, it is because of extreme cost cutting. I have not read any recommendations of over-volting, except yours (and obviously, since I knew "LM3445" from memory, I have read a bit).

There's also a dimmable controller for LEDs -- http://www.national.com/pf/LM/LM3445.html . Someone must be using them in something we can buy. In my copious free time, I hope to use one to build a couple of custom LED controllers for two lights in our house that are dimmable, and need to be dimmable.

A perfect application for my patented write-only memory.

Bob Pease, is that you?

FINALLY !!! AN APPLICATION FOR THE WOM!!!! http://www.national.com/rap/files/datasheet.pdf Bob Pease sure was fore-sighted, since this memory chip was invented back in the seventies!

http://www.national.com/rap/files/datasheet.pdf

"Write only memory" is such a hoary old joke, I'm surprised it got modded up at all. I'm doubly surprised it got modded informative. I'm triply surprised that some people have responded as if I was actually serious.

5 days back I got +2 funny and +1 informative for a DHMO hoax post. So not surprising.

*sigh*

Though it speaks more to powers of observation than common geek sense, I had a similar thing happen at work.

I printed the old Signetics WOM ad and posted it in the impromptu "important papers" space I have behind my desk, along with various other legitimate techie things, like lists of local shops that can do warranty repairs on Model X or Product Line Y. It was ages (literally about 3 months) before someone else from the service department called me on it. (He's the sort who's at home with a soldering iron - it was the bogus block diagram that tipped him off. No one paid the big "WRITE ONLY MEMORY" line at top any mind.)

It sounds like Signetics WOM (Write Only Memory) to me! http://www.national.com/rap/Story/WOMorigin.html

Just goes to show ya that MIT guys will crack a nut using a bulldozer. There's plenty of dedicated level-meter chips around which cost next to nothing and provide a better, logarithmic response, which is what you want for sound.

The LM3915 is an oldie but a goodie, you can even daisy-chain them.

See http://www.national.com/mpf/LM/LM3915.html

Well, I do agree the goats are a lot cuter than sheep.

It's been done, although it was a prank by a Real Engineer, Bob Widlar. http://www.national.com/rap/Horrible/sheep.html

If you want to be even cheaper, make your own. National Semiconductor LM3405 driver chip and half a dozen associated components (this link has what I consider to be the snazziest design software I've ever seen, that'll crank out a list of the precise parts you need and even send them to you) plus a couple Philips LumiLED LXHL-BW02's from Future
Electronics (the cheapest source) and you have a lovely little light that'll run for days off a 9v battery. Since a 9V is a crappy way to run a light, price/performance-wise, you could use a boost driver like an LM2623 to run your LED's off 2 AA cells, and that's an easy design too.
If it's not obvious from the foregoing, I design parts of these chips, so my referrals of their site isn't altruisic. They're good chips, anyway. Although so are Maxim's.

If you want to be even cheaper, make your own. National Semiconductor LM3405 driver chip and half a dozen associated components (this link has what I consider to be the snazziest design software I've ever seen, that'll crank out a list of the precise parts you need and even send them to you) plus a couple Philips LumiLED LXHL-BW02's from Future
Electronics (the cheapest source) and you have a lovely little light that'll run for days off a 9v battery. Since a 9V is a crappy way to run a light, price/performance-wise, you could use a boost driver like an LM2623 to run your LED's off 2 AA cells, and that's an easy design too.
If it's not obvious from the foregoing, I design parts of these chips, so my referrals of their site isn't altruisic. They're good chips, anyway. Although so are Maxim's.

Yesterday you rant about giving up too much piracy, today you rant about them not being readable? I pity those cluelessnesses' failure in appreciating the beauty of unbreakable security with Write-Only-Memory(WOM) technology from Sygnetics in 1972.

Enough about it. Get off my lawn.

You fail at reading comprehension in addition to electronics knowledge. Both 317s I listed were Ts. One was an AT and one was just a T. I gave you a fucking huge clue that the difference was the temperature rating by talking about that difference, but apparently you're too stupid to get the hint. Here you go: The LM317T comes in a TO-220 and is rated to 0 C. The electrically identical LM317AT also comes in a TO-220 but is rated to -40 C. That is a very significant difference and is exactly the kind of difference which distinguishes the components used in consumer electronics than those designed for more robust environments like cars.

My point is, they don't make an LM317T for cars, and a seperate one for consumer grade equipment.

Then tell me why National Semiconductor sell two models of the LM317T with different temperature ratings. Go and see for yourself, I'm not making this up. There is nothing special about National Semiconductor or the 317 - they were just the first manufacturer and component that came into my head. I was rather hoping they'd have some a fancy ceramic mil-spec package as well to prove you even more wrong, but they didn't. Not that such things don't exist, I just can't be bothered to find you an example.

It's an extremely efficient compression algorithm. The only downside is that it's one way so there is no decompression algorithm to go with it. It's a bit like WOM (Write Only Memory).

Charles Kittel, Herbert Kromer, Thermal Physics
Consise, a small set of problems, at least look at every one

Hans Ohanian, Gravitation and Spacetime
Could prevent you from boggling at Misner, Thorne and Wheeler

Stephane Mallat, A Wavelet Tour of Signal Processing
Thorough, a math processor here told us that the demand for rigor could invariably be handled by saying "Lebesgue limit theorem."

Cornelius Lanczos, The Variational Principles of Mechanics (a paperback from Dover books)
Classic introduction to the calculus of variations and analytic mechanics

Paul Horowitz, Winfield Hill, The Art of Electronics
The first edition, before they threw in all the microprocessor stuff, is focused on what experimental physicists need to know.

One of the grand old men of analog chip design, Bob Pease, has written a column for years that you can read on the web.
http://www.elecdesign.com/Departments/DepartmentID/6/6.html
http://www.national.com/rap/

If you want to learn, use the manufacturer's application notes and start from there. Usually they have sample circuits with equations. Buy your parts from Digikey.

Tin Whiskers appear real:

    http://nepp.nasa.gov/WHISKER/background/index.htm
    http://www.calce.umd.edu/lead-free/tin-whiskers/

From what I can tell from these links there issue is still present in lead-free solder, and very much an issue in certain conditions. I have not seen any pages which indicate long-term solutions, though it would be interesting if someone can turn one up.

Another link:

    http://www.national.com/analog/packaging/leadfree

Again, read this.

As for the 1600, the trade-off you have for a true 24 bpp display is narrower viewing angle and slower response time, this is due to the physics of the crystals. Check out the National Semi page for lots of info on what exactly a liquid crystal is, what the different types are and how they're driven, and lots of amusing info on the guts of LCD panels.

But for the dithering, it's sort of like buying CDs with 16 bit samples, but CD players only having 12 bit DACs but it not being written anywhere. But then, if no one can tell, why choose 16 bits in the first place? This reminds me of the waning days of Minidisc when suddenly everyone here became a very critical, golden-eared audiophile and could tell the difference between a CD and MD, but the same people turn around to their 18 bit displays, can't tell the difference, and go on thinking they are 24 bits.

Life on this planet never ceases to amaze and befuddle me.

Now all they need now is faster WOM

Actually I did play with the serial MRAM's back when I was an embedded systems engineer, they were pretty cool. As I recall they didn't have the write cycle count issues that EEPROMs had and had way faster write cycle times.

I'm sure someone could think of a way to make write-only storage very efficiently.

It has been done and I remember when it was announced:

http://www.national.com/rap/Story/WOMorigin.html

I recollect the story of one of the pioneering transistor companies, back in the '60s. They had agreed to ship to their customers transistors with an AQL (Acceptable Quality Level) of 2%, which was pretty good for those days. So the tester would test 98 good parts and put them in the box. Then, following her instructions, she would add 2 bad transistors to finish off the box, thus bringing the quality to the exact level desired. This went on for some time, until one of the customers got suspicious, because the two bad transistors were always in the same corner of the box! Then things were changed ....

You should check out the following website and order an eval board for $350. It will extend DVI or HDMI over 30 meters at 1080p. There's even a version that converts HDMI to CAT5 and back to HDMI so that you can use crappy CAT5 instead of a custom HDMI cable. It can even handle the new deep color HDMI 1.3 spec!

http://www.national.com/pf/DS/DS16EV5110.html
http://www.national.com/appinfo/lvds/dvi_extender_ demo_kit.html

HDMI to CAT5 version: DS16EV5110-EVKC
HDMI only version: DS16EV5110-EVKH

You should check out the following website and order an eval board for $350. It will extend DVI or HDMI over 30 meters at 1080p. There's even a version that converts HDMI to CAT5 and back to HDMI so that you can use crappy CAT5 instead of a custom HDMI cable. It can even handle the new deep color HDMI 1.3 spec!

http://www.national.com/pf/DS/DS16EV5110.html
http://www.national.com/appinfo/lvds/dvi_extender_ demo_kit.html

HDMI to CAT5 version: DS16EV5110-EVKC
HDMI only version: DS16EV5110-EVKH

Reminds me of Earl Muntz of "muntzing" fame.

http://www.national.com/rap/Story/0,1562,17,00.htm l

For example, Muntz would advertise a particular car with a special price as the "special of the day" - a car that had to sell that day. If the car was not sold by the end of the day, Muntz vowed to smash it to bits with a sledge-hammer, personally, on camera. Needless to say, with tricks like that he was able to generate a lot of publicity and interest, and sell a lot of old cars, too.

Like you said, it's already put inside of every lithium battery made, that's not the problem

I admit I'm being a bit of a pedant here, but it sounds like what you want aren't lithium batteries, but lithium cells. I would guesstimate that the mass-produced cost of the safety circuitry is somewhere between $3 and $10, which would double or quadruple the cost of a cell. (a MAX1737 which only implements charge control, not discharge control, is $2.85 for lots of 1000, and requires supporting components. The LM3621 is less expensive at $1.40 but has the same limitations), and some room in each cell (reducing capacity and adding weight). You may find the R/C aircraft hobbyists' attempts to use lithium in their homemade battery packs interesting reading.

If my guesstimation is wrong, there's probably a profitable business waiting for you.

You may be interested in seeing a 100 ft. DVI connection over CAT 6 cable. It was on the most recent episode of the National Semicondcutor Analog by Design Show.

Sure, it's not 350 ft, but it is pure digital, and uses some cool (to me, at least,) techniques like pre-emphasis and filtering to achieve the 100 ft transmission. Also in the episode is a 15m PCIe extender! (The demos are in the last half, the discussion on how it is done is in the first half.)

You may be interested in seeing a 100 ft. DVI connection over CAT 6 cable. It was on the most recent episode of the National Semicondcutor Analog by Design Show.

Sure, it's not 350 ft, but it is pure digital, and uses some cool (to me, at least,) techniques like pre-emphasis and filtering to achieve the 100 ft transmission. Also in the episode is a 15m PCIe extender! (The demos are in the last half, the discussion on how it is done is in the first half.)

I agree, just b/c PCs run at 3GHz today, your dining room creations don't need to. You also should be more specific. What is you background now? Are you a programmer? Are you interested in digital or analog electronics? How much money do you want to put into the hobby? The money part is pretty important, b/c it will dictate the equipment you will have. Electronics hobbyist cover the spectrum of a $5 radio shack soldering wand and components robbed from discarded equipment, to high dollar equipment bought at surplus auctions. For the digital domain, it makes sense to use a microcontroller, b/c it cuts down on component count as compared to logic chips. For a $230 you can get a Microchip ICD2 and development board from www.digikey.com, P/N DV164006-ND. Microchip has a very good user community at http://forum.microchip.com/. If you want to spend less money, there are many plans on the web for do it yourself bootstrap programmers for PICs. I reccomend the ICD2 if you can afford it. It supports a very wide range of parts from Microchip, and the development board will save you a lot of time in building. In the analog domain, the operational amplifier is the heart electronics. A great place to start, if you have not already, is to build math functions with op-amps... dividers, multipliers, integrators, et. As you perfect different analog circuits, you can start to combine them into larger circuits. Depending on the money your willing to invest, there a lot of good books available. The first I would suggest, and I've seen it in other posts in the this thread, is The Art of Electronics. It's a good general reference. Also, it can't be overstated, the wealth of information available on the web in the form of manufacturers datasheets and application notes. www.national.com is a good place to start looking for datasheets. They have some really good online tutorials, check out there analog university, http://www.national.com/AU/. Wikipedia links to some good resources as well in their electronics articles.

How about Brazil's voting machine system... electronic count, voter veririfed paper trail, randomly selected precints for recount

I don't post here very often, but this time I couldn't handle this. (Maybe I should drink less coffee). There was probably some paper at that uni, talking about an incremental improvement in frequency divider design. Ok, cool ... we may or may not see in in a PLL chip in a few years. But the news release (TFA) and RP's writeup are rubbish. Actually, after a bit of Googling, it's all over the net. Next thing I expect, my PHB will ask me to change my totaly unrelated design to use ILFD. My signature notwithstanding, I'll try to pick out some of the c***p, and put some actual information in. BTW, I design 3G mobile terminal circuitry full time. And yes, I am an arrogant SOB. That doesn't make me wrong.

"...But now, researchers of the University of Rochester have developed a wireless chip that needs ten times less power [GC] than current designs."

So far so good.

The new chip relies on a technology named injection locked frequency divider (ILFD) which dramatically reduces the time needed to check for transmission frequencies which are performed several billion times per second by your current phone.

This statement is wrong 2 times. First of all, the time needed to check for transmission frequencies depends on PLL settling time. Nothing to do with divider technology. Even broader scope, it is a rare occurence in 3G that the phone needs to change RF frequency. It's WCDMA, so all cells from a given operator transmit on the same channel. Secondly, tthe checking for transmission does NOT occur "several billion times per second". The RF carrier frequency is several billion cycles per second (ie several GHz). But the carrier frequency is changed on every 10ms roughly, even when it needs to happen. That's 100 times per second. GSM is different, as it does frequency hopping normally, but that doesn't change the point: nothing to do with divider technology.

The new chip uses five transistors and can perform divisions by 3 instead of only 2 by previous circuits

OK, agreed. Anyway, who gives a f**k. A modern PLL chip has a programmable divider, settable from 3 to several thousand. Yes, 3, because it is different technology.

..., allowing a perfect communication between two phones communicating at 2.0001 and 2.0002 gigahertz respectively.

That's not how mobile phones work. Mobiles establish connection with the cell (base station), then remain frequency locked to it, to compensate for temperature dependant frequency variation of their reference reference crystal oscillators - and Doppler shift, if they are moving. A "perfect" communication hardly ever depends on this. And frequency locking does not happen via changing PLL settings in this case anyway - too coarse steps, so other techniques are used.

Anyway, as other people posted already, the frequency synthesizer is not significant contributor to mobile terminal power consumption. Even old PLL chips only use a few milliamps

The ILFD technology seems to be good for building efficient frequency dividers at higher microwave frequencies. That will probably not affect current mobile phones anyway, because all the current systems work around 1-2GHz. Higher up, it's difficult to achieve coverage. Again, other people already pointed this out.

If you want real news in this area, go to sites like this, or this. Slashdot's editorial quality has degraded in the last few years so much that I am thinking about deleting it from my bookmarks.

National Semiconductor Geode Origami

That's the National Semiconductor Logo ... national.com

National made most of the electronics for Microsoft's spot watch.

That's the National Semiconductor Logo ... national.com

National made most of the electronics for Microsoft's spot watch.

There's a problem: Macrovision. They deliberately put high-voltage pulses in the vertical retrace interval of some frames to confuse the automatic gain control in the recorder. The AGC sees the spike, winds the gain down and you get a dim picture for several frames. Then it goes bright again. Then they put in another spike and it goes dim. As far as protection schemes go, this one is totally christian. You will just need a DVD player with the option to disable Macrovision; a VCR with RGB inputs; an RGB to composite encoder {NB; must be the appropriate video standard, PAL, SECAM or NTSC, for your region}; a timebase corrector; or an image stabiliser.

One very simplistic way to defeat Macrovision is to build a simple level-limiter circuit, so the extraordinarily high voltage pulses sent in the vertical retrace interval will be clamped to peak white level {1V} before they reach the VCR. This is really nothing more than a DC-coupled, non-inverting, high-bandwidth version of a guitar distortion pedal.

To build a more sophisticated timebase corrector, use a 1881 sync separator to get the timing signals, and some sort of bilateral switch {a 4016/4066 will sort of just about do, but look at the Maxim web site for some higher-bandwidth, lower-on-resistance ones} to switch between the existing video signal, and a locally-generated "black" signal {about 0.3 volts}. The 1881 has a composite sync output which should be used to add "clean" timing to the artificial black {just force it down to 0V when the timing signal goes low}. Be sure to use op-amps with a decent slew rate, not 358's! You will also need either a bunch of TTL ICs {if you're hard} or a microcontroller. At the beginning of each frame, switch to "artificial black" for about the first 20 lines of picture, then switch to the real picture for all but the last 20 or so lines, which should be replaced by more artificial black. You may need to experiment with the number of lines you strip out. If you are 500p3r l33t, you might even care to insert your own locally-generated Teletext information in the newly-created vertical retrace interval; but don't expect this to come out right on a VHS recorder.

Sir,
Your helpfulness, while noble, is probably better left aside here, as you are a little out of your element here. A datasheet in the electronics industry refers to a specific document that will give you all the details about a chip, including pinouts, schematics, functions, wiring diagrams, applications, etc. For an example, look at the classic and basic LM741 Op amp http://www.national.com/ds/LM/LM741.pdf Sometimes these are available on the web, sometimes they are proprietary and you need to sign a mountain of disclosures before you can acquire them. The one he is looking for, appears to not be available through any of the normal channels.

I noticed the absence of the caps also, I assumed that it was because there aren't any transients in the supply to filter, since the regulator is practically attached to the battery by its leads, and the load doesn't have any high-frequency draws that would require the second cap downstream of the regulator. At least I'm hoping that's the case, it could also be that whoever did the first version didn't put any on, and everyone else has just copied that. :)

Interesting suggestion about the diodes. I don't think I've seen that method used in any of the versions around online. I wonder how it would work though as the battery drains and the input voltage decreases: with the regulator you at least have a little extra headroom (the LM7805 needs 7.5V to maintain 5V output, IIRC) so that you'll have a stable output voltage for a while as the battery runs down (from 9.5 or whatever it starts off at to 7.5). Maybe if you used a rechargable battery with a fairly flat discharge curve this wouldn't be as much of an issue, but I could see it being one with an alkaline.

But your point about the quiescent current is a good one. Perhaps the low tech solution would be to just install a small power switch between the battery and the regulator. When the Shuffle's internal battery is low, attach the charging contraption and turn it on; remove and turn it off after you've given the internal battery a quick charge.

Those LP29-series regulators are pretty impressive. I think I might have to order a few LP2954s. It's a slightly higher current (250mA) than the one you suggested but still with quiescent current of 120 uA. Comes in a TO-220 package and they'll sell samples directly to individuals.

One thing I must have missed in my summary of the MA article: it's necessary to tie both of the data pins in the USB cable to Gnd if you want the Shuffle to charge properly. Example with photos (in a honking big project box compared to the Shuffle) here.

PDF files are very useful to distribute printable materials, such as books, spec sheets, PR and corporate bullshit (ugh), brochures, etc

HTML can be used in the same roles, and without loss of functionality

So far -- and it's been some years now since PDF arrived -- I've never seen a single PDF document that I thought needed to be a PDF document.

There doesn't seem to be any readily available commercial multi-bank DC adapters out there. This is quite surprising since the solution is pretty simple. The solution requires a switching power supply that generates a DC voltage that is somewhat higher (at least 3V) than the highest voltage required to be generated, and a bank of LM317 programmable voltage regulators. In this configuration, each LM117 can provide up to 1.5A of current. If necessary, LM318 or LM150 devices that support higher current can be used. LM117s package sell for about 50c each, so this would be a relatively low cost solution.

Here's a clue: you'll need an LM1881 sync separator, a 4053 bilateral switch {or preferably something with more bandwidth}, and either a PIC microcontroller or a stack of TTL chips. The 1881 has an output which tells you when the field starts, and another output which pulses on every line. You need to count off 20 or so lines {look at the picture signal with an oscilloscope to see where the real picture starts}, during which time you must output a dummy black level with artificial hsync pulses. {You can get a clean hsync output from the 1881; use this to turn on a transistor and pull the black level down to 0V. Your dummy black needs to be as close as possible to true black, otherwise the very top and bottom of the screen will be some shade of grey. But you'll have thought of that and wired in a potentiometer to adjust it}. Switch over to the unadulterated picture signal for about 270 lines. Then go back to your dummy black for the remaining {22.5 or thereabouts} lines of picture.

If you need adjustability, use a PIC with a decent number of I/O lines. Or try using an open-drain I/O line with a capacitor to 0V ..... pull it low to discharge the capacitor; let it float, allowing the cap to charge through a pot; and time how long it takes to begin reading high. The paddle controller inputs on the Atari 2600 worked exactly like that.

Or, you can get a proper time base corrector from a professional video equipment supplier. It'll probably cost you more than buying a load of original videos, though ..... :)

Connecting the 7805 regulator as shown to knock down the 12V rail to 5V means that at the 7805's short circuit current limit of 2.1A, the regulator will make (12-5=7) 7V*2.1A=14.7 Watts whereas the procs will dissipate 5V*2.1A=10.5 Watts. In other words, the only thing I can see outputting enough power to even warm the pan is the meter on my bs detector.

7805 DataSheet

the appropriate ADC from National Semiconductor ADC12L066 are 20 USD a pop, not what I call super expensive...

man, whatever happened to the garage tinkerer spirit from 10 years ago ?