Question for older engineers, how did you get info? - Page 1
Forum section: electronics / general

author: lazyman
author_rank: Contributor
timestamp: January 16, 2020, 06:11:12 pm
content: Hi.I have a few electronic board from moving light fixtures. Electronic is a bit dated, but component are still in production and use.Main are 8051 compatible micro, l6219 motor driver and TLC7528 dac. On two board problem is microcontroler, and i don't have code.Thinking about writing some, but cannot find any info, example, primer, how to use this together.This raises a question, how does engineers know how to use and pair this components, if there is no info that all this combined can be used for given purpose? Is there some "secret" datasheets or manuals or some instructions not publicly available?And how company sold this ic's with such sparse information about usage of them?

author: up8051
author_rank: Frequent Contributor
timestamp: January 16, 2020, 06:20:08 pm
content: They know, because they are engineers

author: edpalmer42
author_rank: Super Contributor
timestamp: January 16, 2020, 07:06:35 pm
content: Every company produced thick data books full of datasheets. For more complex circuits like micros, there were design guides that combined datasheets with tutorial info on how to use them. There were also lots of training courses that gave you a hands-on experience with the hardware.I suspected that I'd find something at the Internet Archive. I did.https://archive.org/details/bitsavers_intel8051M1_25397633This one popped up on the first page. There's probably lots more there. I searched for < 8051 microprocessor > and specified "search text contents" .Ed

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: January 16, 2020, 07:10:13 pm
content: Once or twice a year we'd drive over to one of the major distributors in the area and fill up our trunk with hundreds of pounds of data books.

author: tggzzz
author_rank: Super Contributor
timestamp: January 16, 2020, 09:14:48 pm
content: We gathered whatever information we could get our hands on, and devoured it carefully to extract everything we could.Then we sat down andthought, and understood.Nowadays the key skill is the polar opposite: to quickly decide what toignore.In other words, theconceptof stackexchange was alien and would have been dismissed as "monkey see, monkey do" trivia.

author: Gyro
author_rank: Super Contributor
timestamp: January 16, 2020, 09:38:35 pm
content: It was a different world. Distributor and semiconductor rep visits were something to look forward to. They bring armfuls of databooks which we would scrabble over and jealously guard, writing our initials across the top of the closed book for easy identification. Reps would also bring goodies, ranging from mugs to component sample boxes (I still have a few). I still keep a lot of my old databooks for nostalgia, and for reference on parts that never made it to the web in readable form.Component selection for stuff that wasn't in the databooks was a case of phoning around to see what everyone had and then waiting for them to send a datasheet by post. If you were really in a hurry, they would fax something unreadable too!

author: CatalinaWOW
author_rank: Super Contributor
timestamp: January 16, 2020, 10:32:49 pm
content: Yep, it was a different world. All those data books and manuals were paid for out of the marketing budget, often at the local distributors level. So if you weren't perceived as a someone likely to result in volume purchases you had real trouble getting access to the books. Begging for old ones from engineers at big companies was one path. Libraries at engineering schools sometimes got a set, as did some favored professors who might be willing to share. In some cases they could be purchased, but they cost about the same as textbooks. Hobby folks depended a lot on magazines and books written by those who had access to the original materials.In the really old days there were some unusual sources. The Handbook of Chemistry and Physics, a large collection of math tables, material properties, chemistry and other general data which used to be a must have resource for scientists and engineers in the mid-1940s contained tube base diagrams for all of the most commonly used tubes (valves for those who speak other forms of English). The Handbook is still published, though it has eliminated much material more easily obtained on the internet and is worth investigating if you are not already familiar with it.There is a lot to like about the way it is today with widespread access to most of the data.

author: Alex Eisenhut
author_rank: Super Contributor
timestamp: January 17, 2020, 12:01:28 am
content: In the 1990s, you had to get referred by someone already initiated.My first tech job in the mid 1990s, I had next to no data books or data sheets except what school handed out.I talked to the engineers there and they gave me subscription cards to free trade magazines.These magazines (with my name on the address label! Yay!) where half full of advertisements and reader reply cards in the back.Each advertisement in the magazine had a number, and you'd circle the number on the card and mail it for free.Then you'd get more and more stuff by mail. Eventually you'd get visits from manufacturer reps and distributors and they'd offer entire sets of databooks, shelves and entire libraries full of free books were built this way.There were also fax back services. You'd call a toll free number, follow the automated system, enter in the chip number you wanted, entered your fax number and you'd get a data sheet faxed over. Then I'd copy the fax to real paper (old faxes on thermal rolls were flimsy).Then when CD-ROM drives came down in price companies like Intel would supply all data on CD.One day in the mid 2000s, I think, my entire collection of books and CDs had become oppressive and I tossed it all out on recycling day.

author: DTJ
author_rank: Super Contributor
timestamp: January 17, 2020, 12:47:40 am
content: Anyone recall the RS Components data sheets?I knew a RS sales rep, he gave me a complete set of data sheets. It was around 1 cubic meter of files and paper. They used to be great sources of information.

author: ferdieCX
author_rank: Regular Contributor
timestamp: January 17, 2020, 01:57:46 am
content: In the 70's, it was possible to buy the RCA Databooks for a reasonable fee (Spanish version printed in Argentina).The ones from Motorola were a lot more expensive and not so easy to get (imported from the USA).The Philips Pocketbook was also available. I still have them all.If you needed a Datasheet that was not there, you had to see if a distributor or someone else had it and to beg a photocopy

author: Turbinedave2003@yahoo.com
author_rank: Newbie
timestamp: January 17, 2020, 04:44:09 am
content: Manufacturers published data sheets and application notes for the device in question. Reference designs by the device makers were often available to show the device in a working circuit. Custom code in the form of the specific microprocessor machine language was stored in the form of EPROMS or EEPROMS or ROM. The code can be reverse engineered by reading the contents of the EPROMS, etc. Before the internet it took a phone call and FAX machine and snail mail to obtain data sheets. Sales reps from distributors were sometimes helpful, especially if you company was a big buyer. A call to the device maker was also helpful in obtaining the information one needed. It helps to know other designers and engineers from where one could get help. No engineer knows everything. Today the internet makes research fast and easy. Especially looking for devices no longer made, and many decades old. Of course one must have the wide breadth of knowledge and understanding of electronics outside the scope of this reply. There are things no school or book or professor can teach, as it takes decades of hands on real world design and experimentation, and failure upon failure before becomes an accomplished "Grey Beard."

author: worsthorse
author_rank: Super Contributor
timestamp: January 17, 2020, 05:25:58 am
content: In the late 70s and early 80s, if you were an engineer working in a startup, data books and application notes were pretty easy to come by, at least for semiconductor components and test equipment. For the component vendors, the goal was to be designed in. For the test equipment vendors, it was to sell dozens or hundreds or scopes or logic analyzers or whatever. Data books and applications engineers were theonlymarketing tool for lots of these companies.So companies like TI, Motorola, and RCA published tons of application notes, reference designs, and theory and practice manuals (like GE'sTransistor Manual) that were mostly available for free. Every digital design engineer I knew had a full set of manuals from TI. The analog engineers had a similar set of stuff from Analog Design.But it was a different time... design engineering, at least at the bleeding edge, was still more an art than engineering, there were few software design tools, integration levels were, compared today, very low and product life cycles were longer. In that kind of world, data books were a good investment of a vendor's marketing dollars.

author: Berni
author_rank: Super Contributor
timestamp: January 17, 2020, 06:49:24 am
content: Well paper databooks are still around.For example Wurth Elektronik left a few phonebook sized product catalogs here last year. But it is not something i would flip trough to find the part i need. It's more useful for just flipping trough it idly and seeing what sort of stuff they have, sometimes a special funky connector catching your eye that you didn't think existed but would be a perfect fit for your latest project.But yeah sales reps from big semiconductor vendors have left paper behind long ago. The most you get is perhaps getting a dev board loaned to you for free via a distributor.I was not around in the 80s to know how it was for any of this, but i am sure glad the internet came around and made electronics documentation so easily accessible.

author: spudboy488
author_rank: Regular Contributor
timestamp: January 17, 2020, 01:17:55 pm
content: Quote from: Gyro on January 16, 2020, 09:38:35 pmI still have and, occasionally use, my copyright 1978 "Signetics Logic-TTL Data Manual" with my name on the front cover as well as the top of the closed book.

author: nctnico
author_rank: Super Contributor
timestamp: January 18, 2020, 03:24:23 pm
content: Quote from: Gyro on January 16, 2020, 09:38:35 pmFortunately Wurth is still doing that. Their Christmas chocolate was great!

author: ebastler
author_rank: Super Contributor
timestamp: January 18, 2020, 03:38:12 pm
content: Quote from: lazyman on January 16, 2020, 06:11:12 pmI am not sure what question you are asking. Is it that you can't find the datasheets? Others have nicely described how these were obtained and distributed in the old days. But today datasheets for all the components you mention are easily available online -- so I can't see how that would be an issue.Or is it that you cannot find tutorials on how to combine these specific components? In that case, the answer how engineers used to (and still do!) deal with this was already given:Quote from: up8051 on January 16, 2020, 06:20:08 pmSeriously: How to drive, from a microcontroller, peripheral components with various serial/parallel data lines and handshake signals is something you have to understand once, in principle. Then you can apply the fundamental concepts to whichever components you need in your system. The datasheets do, and always did, provide the necessary specifics for each peripheral and for the microcontroller.

author: worsthorse
author_rank: Super Contributor
timestamp: January 18, 2020, 06:14:50 pm
content: Quote from: ebastler on January 18, 2020, 03:38:12 pmWhat this person said!There isn't really any "secret documentation" other than the proprietary or trade secret material that vendors give only to companies that sign NDAs and are likely to commit to big parts orders. But you are unlikely to be designing with a part like that. And while there are lots of websites and books that will give you "recipes" for certain kinds of circuits, unless you need exactly what they've designed, they aren't likely to be terribly helpful.If you want to design electronics or get a microcontroller to perform some task, you have to commit time and energy to learning how to use electronic components, setting up a development environment, and so on. Some of us start out building stuff from kits or getting a book that has recipes and learn design in an ad hoc way. Others go to school and learn in a more structured way. All of us probably have people that will answer questons when we have them.I learned design partly in school, which taught me a lot of basic theory, and working in an engineering lab where I learned a lot of practical application. I studied a lot of other people's designs and was tasked to design things with specific functions: a laser printer interface, a memory board, a bit slice processor, etc. I read a lot of data books, I built a lot of stuff that didn't work, I fixed a lot of stuff in the lab and on production lines. And with all that, I was only good at one tiny corner of electronic design. That's how it goes.

author: ciccio
author_rank: Frequent Contributor
timestamp: January 18, 2020, 08:23:00 pm
content: I keep in my library a copy of a PHILIPS data book that dates back to 1966/67.It's 731 pages, and covers tubes (valves) of every type, from audio to RF to picture tubes to phototubes, transistors and other semiconductors.There is also a chapter on ferrite cores (Philips' name was FERROXCUBE).I had to buy my copy, because it was one of the textbooks for the Electronics course at my technical high school.Back then you had to pay for data books: they were available through electronic components dealers.When I began working for an elecronic manufacturer the manuals and data books were free, plenty of them.At the annual clearance of the lab and the office, I got all the duplicates or older editions and gave them to my friends.I was paid in pizzas and/or wine.Nice days...

author: SiliconWizard
author_rank: Super Contributor
timestamp: January 18, 2020, 08:38:00 pm
content: As others have noted, I don't quite get what the question of the OP really is. Is it about how hard it was to get datasheets compared to how easy it is now with the Internet? Or about how to use electronic parts to design a whole circuit? The latter is obviously just engineering. It hasn't changed. It's still your job to know how to use existing parts to design something new, it's exactly what engineering is all about.To get ahold of datasheets and app notes, it was obviously not as easy as it is now. Sometimes you even had to pay to get some documentation! Otherwise, you could get free large books at conventions or things like that, or if you were part of a company that was a good customer for one of the big semiconductor vendors...I think many people these days are biased due to all the information that can be found on the web, and how easy it is to just go to a forum and ask questions. In the past, people actually had to resort to 1/ thinking, 2/ networking and 3/ talking with actual colleagues. Yes, that was a thing back then.

author: worsthorse
author_rank: Super Contributor
timestamp: January 18, 2020, 10:01:40 pm
content: A couple or three months ago, I had the opportunity to acquire a collection of data books, mostly from the 80s and 90s, for the cost of shipping. So I ended up with five big boxes of books from TI, moto, rca, philips, AD, etc. Looking through them, I would guess way more than half of it covers unobtanium parts.They are really a lot of fun to page through (memories, memories!) and give my ever tolerant wife something new to tease me about, but there is very little in all those zillion paper pages that I can't find on the interwebs (or don't already have in my electronic data sheet library). The biggest advantages to having them, besides the nostalgia buzz, is seeing device data in context and originals are often easier to read than the scans.The application books are a little bit different in the sense that what they teach is often device-independent. For example, lots of the design info in GE'sTransistor Manualand the AD application notes is still useful today. But even that is mostly available on the web.So it is a lot easier to be a non-professional designer/builder today than it was then because so much of this material is a single google away. But... having access to data is not the same thing as knowing what to do with it.

author: joeqsmith
author_rank: Super Contributor
timestamp: January 18, 2020, 10:09:28 pm
content: Sales reps would come to the places I have worked with their car loaded with data books. We would go through them and pull what we wanted. We also got sample parts this way. Eventually we started getting CDs but the MFGs each had their own formats. I still have a few binders of CDs but have been slowly recycling my paper copies. Then came the internet.

author: nctnico
author_rank: Super Contributor
timestamp: January 19, 2020, 12:43:53 am
content: Quote from: SiliconWizard on January 18, 2020, 08:38:00 pmGoing to second hand/surplus book stores trying to get a haul of interesting books for little money worked well for me. And don't forget to mention bulletin boards. I recall getting a whole bunch of software for HC11 development from a bulletin board. Which wasn't simple because the owner put some kind of vetting process in place where he called the people trying to contact the bulletin board before allowing access. Yes, those where the days

author: nigelwright7557
author_rank: Frequent Contributor
timestamp: January 19, 2020, 10:53:19 am
content: Quote from: lazyman on January 16, 2020, 06:11:12 pmBoth then and now you can find loads of info on 8051.It was/is a popular microcontroller.I used a datasheet and bought a book on the instruction set in the 1980's.

author: tggzzz
author_rank: Super Contributor
timestamp: January 19, 2020, 10:58:34 am
content: At this stage it feels like the OP is living up to his moniker / username

author: Siwastaja
author_rank: Super Contributor
timestamp: January 19, 2020, 11:07:29 am
content: Even to this day, I seldom need much more material than the chip documentation / datasheets. They always existed. So nothing really changed, except you had databooks / photocopies thereof, now you Google a PDF.Tutorials are a good way to introduce total n00b to electronics. They existed in form of printed magazines back then.

author: Gyro
author_rank: Super Contributor
timestamp: January 19, 2020, 12:39:10 pm
content: The Nat Semi Linear Applications handbooks were always a good read, and mostly still very relevant today. You can find most of the App notes on the web, but it helps to know the AN number (I'm still looking for the one for the thermally servoed contact temperature sensor that was in one of the earlier editions I gave away!).

author: ebastler
author_rank: Super Contributor
timestamp: January 19, 2020, 12:55:36 pm
content: Quote from: tggzzz on January 19, 2020, 10:58:34 amYep, I had been wondering whether I should mention to him another "secret ingredient" engineers use to solve design problems: An extended attention span.

author: tggzzz
author_rank: Super Contributor
timestamp: January 19, 2020, 02:19:05 pm
content: Quote from: ebastler on January 19, 2020, 12:55:36 pmTee hee. Too true.

author: rstofer
author_rank: Super Contributor
timestamp: January 19, 2020, 05:28:29 pm
content: Back in the early to mid '70s, microprocessors were a new thing. There was no market for them, nobody had every used such a thing. The manufacturers knew this and they went out of their way to publish databooks, app notes and other handouts to help designers bury uCs in their products. These books were given out freely, even to hobbyists because hobbyists were just as advanced as working engineers, none of us knew where things were going. We just had to get somewhere and do it fast.It was a great time in my life. The 8080 was available ($360), the Altair 8800 came out (somewhere less than $400 and that included the chip) and I was in grad school where we did our 1 unit Engineering Seminar writing papers about all of the new microcontrollers and their features. We were flooded with manuals and handouts.Nobody knew anything and we were all learning together. Fun times!And I worked for one of the largest semiconductor companies in the world, circa '76. Datasheets and manuals were all over the place. If you didn't know something, well, somebody did! Hunt them down...But you designed by yourself. There may have been design teams but I wasn't part of that world. I got the books, read through the app notes and started designing. It was fun. It also consumed a LOT of time.Obviously, we didn't have the Internet to guide us along. That may have been a blessing! We actually had to READ the manuals, not rely on somebody else's interpretation.

author: rstofer
author_rank: Super Contributor
timestamp: January 19, 2020, 06:06:38 pm
content: The 8051 is a very well understood device and is still in production. In fact, there are many advanced versions that have internal flash and RAM memory and are far easier to use. But they still share the same architecture.https://www.nxp.com/docs/en/brochure/75015973.pdfThe L6219 motor driver is not unlike any other bipolar stepper motor driver. Figure 4 needs a lot of thought because it shows 1/3 current position holding, 1/2 current low speed and full speed. Notice all the clocking shown in the middle panel. This will take a little experimenting to figure out. But it's all laid out and there is an application example. Note that current is limited to 1A peak and 0.75A continuous. That's not a lot!Speed control is done by the rate at which pulses are sent to the driver - step commands. This implies the use of at least one internal timer and some way to programmatically control the rate. Timing (and interrupts) are everything.https://www.st.com/resource/en/datasheet/l6219.pdfThere should be a ton of information on driving stepper motors with a uC. Not necessarily an 8051 but the logic will be the same even if the code is totally different.The TLC7528 DAC is a 2 channel parallel load DAC. The application information in Figure 3 and Figure 4 is quite complete. Again, a breadboard and some experimental code will be required.I'm not sure what the DAC is doing relative to a stepper motor but I don't know anything about the end application either.https://www.ti.com/lit/ds/symlink/tlc7528.pdfIt seems to me the OP needs to know a good deal more about the overall architecture of the existing boards. A wee bit of reverse engineering will probably be required. But the real work will be in writing the code. Step one is to get all of the components talking together and step two is to get them to work in a real application. This isn't going to happen overnight. There's a lot to learn by reverse engineering even if the code isn't available. How did the thing work? What are the limitations of the application? How do I apply one of the newer 8051 clones so I can get out of the EPROM business? I want onboard flash and RAM! How much did the original board have.I might go so far as to walk away from the 8051 architecture and just use an ARM chip because the tools are more readily available and the processor is much more capable. I really didn't like programming for an 8051 clone, even in Pascal (which I love). That lower memory thing is a bother!If the existing board uses external EPROMs, it will be easy to extract the code - not that it will be fun - but it should be possible to get to an assembly level. Of course, given an optimizing C compiler, the assembly language will still be obscure.Given that I am kind of lazy, I would probably design a brand new system using an ARM even if I did wind up using the same peripherals. Of course, 3.3V vs 5.0V will jump up and bite me in the butt.

author: rstofer
author_rank: Super Contributor
timestamp: January 19, 2020, 06:17:00 pm
content: Engineers solve problems by beating them to death with a club. We build up sample circuits, breadboarding perhaps, then writing code until we understand all there is to know about interfacing to some device. We look for the 'corners', places where the external device shouldn't go. We try multiple approaches to coding a device, looking to gain intuition. Basically, we beat it to death with a club.Over many hours...

author: nfmax
author_rank: Super Contributor
timestamp: January 19, 2020, 06:28:25 pm
content: Quote from: Gyro on January 19, 2020, 12:39:10 pmIt's Peter Lefferts,The monolithic temperature transducer - a new interfacing concept, AN-132, December 1974, inNational Semiconductor Linear ApplicationsVol 2, 1976. The servo shield is on page AN132-5. I have a paper copy if you still can't find it.

author: fcb
author_rank: Super Contributor
timestamp: January 19, 2020, 06:31:12 pm
content: You have to remember that 'back in the day' we had a fraction of the number of opamps/dacs/adcs/psu IC's/microcontrollers and VERY few RF IC's. So most designs had a much higher component count than today - building a wireless transceiver would involve possibly hundreds of parts, especially if you had a synthesizer and two IF stages.Electronics journal editorals or adverts would introduce you to new IC's, you'd ring or FAX the vendor or a distributor - they'd post out datasheets. TI did well as they often blister packed a sample with the DS. RS did datasheet 'packs' you could buy(!) and update these giant squishy covered blood-red ringbinders with. Most distributors published pinouts in the actual catalogues.I had a 200sqft room that was wall to wall databooks including several yards of National books (BIBLE!), Texas blue/yellow books and Linear Tech pamphlets (application notes). All binded off when PDF happened - feeling nostalgic.

author: Gyro
author_rank: Super Contributor
timestamp: January 19, 2020, 07:21:16 pm
content: Quote from: nfmax on January 19, 2020, 06:28:25 pmThanks nfmax, at least I know which one I'm searching for now. Sadly it took me a little while to notice that they were quietly dropping ANs between revisions, otherwise I would have jealously guarded the old ones too!So much info didn't withstand the transition from the 'old days' to the current one. It's a case of scan it or loose it before it gets pulped (and then watch it drop down the search results until it's never to be found again!), eg, most searches only throw up the 1994 Linear Apps Manual.

author: Noise Floor
author_rank: Regular Contributor
timestamp: January 19, 2020, 07:42:53 pm
content: Quote from: tggzzz on January 16, 2020, 09:14:48 pmSo accurate. Making this transition as access to information became pervasive took a while for many to adapt to. That said, there is a balance to be had between the two extremes, those folks usually are the most productive in my experience.

author: profdc9
author_rank: Frequent Contributor
timestamp: January 19, 2020, 11:50:54 pm
content: I worked for Motorola and so of course I got their databooks and used their parts. A lot of really smart people worked there and I learned from them when I was younger. I'm not even sure engineering organizations like Motorola exist anymore that keep talent like that long-term. Motorola was supportive of electrical engineering education and provided databooks to the labs where I went to school, the University of Illinois at Urbana-Champaign. Motorola was based out of Chicago so that was a no-brainer for them, as many of their employees were graduates of UIUC.But despite today's information overload, yes it's way better to just to be able to get the information you need right away. I don't feel nostalgic for the need to keep a huge set of manuals on hand. I discarded mine a long time ago when I had to move between cities. Breaking down barriers for engineering and creativity, as far as I can see, is always a good thing.

author: schmitt trigger
author_rank: Super Contributor
timestamp: January 20, 2020, 02:28:58 am
content: If you lived outside the USA, Canada or Western Europe, obtaining databooks in the 1970s was also very expensive.Unless one worked for an University or large trans-national corporate, one had to order and pay for the databooks. On top of that, international shipping costs and customs fees.The poster above who worked for Motorola may remember a set of three brown-cover databooks, dedicated to the discrete semiconductors in Motorola’s portfolio. The first two were for JEDEC-registered devices, the last one was for Motorola numbered devices.For the set I paid, after all was said and done, close to $US 80. And those were 1970’s purchasing power dollars.Likewise, for the Texas Instrument’s TTL Data Book for design engineers, the one with the ocre colored hardcover, I paid $US 45.

author: lazyman
author_rank: Contributor
timestamp: January 23, 2020, 11:33:50 am
content: Quote from: edpalmer42 on January 16, 2020, 07:06:35 pmHi. Thanks a lot for this info, i have not know about the archive.org. Fine resource for texts before internet.