Monitor RS232 comms with millisecond resolution
in [Embedded]
|
Prev: MAKE UPTO $5000 PER MONTH! $2000 IN FIRST 20 DAYS!
Next: Dexcel Electronics Designs is Hiring in Chennai
From: Jon Kirwan on 24 Jun 2010 03:46 On Thu, 24 Jun 2010 09:10:13 +0200, "Meindert Sprang" <ms(a)NOJUNKcustomORSPAMware.nl> wrote: >"Jon Kirwan" <jonk(a)infinitefactors.org> wrote in message >news:8715265o00dgu3msi6bra5d51n3sj2npvs(a)4ax.com... >> Not so. I'm looking right now at two such cards, one ISA and >> one PCI. The ISA board has a large, socketed crystal module. >> The PCI a tiny, SMT unit. The skills required for modifying >> one is much different > >Once you've done it a couple of times, you wonder why you ever made such a >fuss about it :-) :) I have put some effort into it, before. >Bu then again, I am an embedded software and hardware guy.... Well, there is that. I am only a hobbyist on the hardware side. Jon
From: Jon Kirwan on 24 Jun 2010 04:11 On Thu, 24 Jun 2010 08:57:40 +0200, David Brown <david(a)westcontrol.removethisbit.com> wrote: >On 23/06/2010 23:50, Jon Kirwan wrote: >> On Wed, 23 Jun 2010 21:04:55 +0000 (UTC), Grant Edwards >> <invalid(a)invalid.invalid> wrote: >> >>> On 2010-06-23, Jon Kirwan<jonk(a)infinitefactors.org> wrote: >>>> On Wed, 23 Jun 2010 14:13:14 +0200, "Meindert Sprang" >>>> <ms(a)NOJUNKcustomORSPAMware.nl> wrote: >>>> >>>>> "Paul Keinanen"<keinanen(a)sci.fi> wrote in message >>>>> news:9pe3269vevlnos3fn3j1ne6dv7tnfgm293(a)4ax.com... >>>>>> At 62.5 kbit/s the bit time is 16 us, thus +/-8 us error from the >>>>>> nominal sampling point from the middle of the bit period would be >>>>>> allowed. >>>>> >>>>> Funny, all the discussions about baudrates and errors. I'd use an ISA COM >>>>> card and simply replace the crystal... done it, works like a charm. Only 5 >>>>> minutes work. >>>> >>>> Hehe. But this means you actually _have_ something with an >>>> ISA bus on it!! These days... well. >>> >>> Then use a PCI card. >>> >>>> On your point, yes. A crystal change on any of the usual >>>> spate of old ISA boards would easily solve the problem. >>>> Forgotten lore. >>> >>> It works for PCI cards as well. >> >> I like ISA and simpler software. >> >> Although I understand reflection wave principles, clock line >> skew and serpentine clock lines, and the like, I very much >> appreciate being able to use simple logic, wire-wrapping >> techniques, and custom circuit design with the ISA bus. It >> is a low-tech bus that can be reached by hobbyists. PCI, and >> not merely because of the hardware but also because of other >> aspects (plug and play), out of reach of most hobbyist tools >> and skills. >> > >ISA has also always been out of the reach of the hobbyist. Are you just in a contrary mood, today? No other explanation is possible. Out of reach??? Hardly. But I suppose it depends upon what is, is. :) >While there >is no doubt that it is simpler to design an ISA card than a PCI card, in >the days of ISA it was hard to make such a card. IBM, itself (and I know this because I still have them here), sold very cheap proto boards for the ISA bus as far back as I can recall. Very beautiful boards, too. I believe I paid close to $30 for each. 1984/1985. >Information about the >bus wasn't as easily available (no Google), Hogwash. I still have my technical reference multi-volume binder set from IBM with __complete__ documentation. Very complete. Complete BIOS listings, with comments, included, and schematics as well. I used these routinely for hobby playing. They were available in 1983 and IBM sent regular updates as new boards came out. For example, volume 3 includes a section I used called "IBM Personal Computer General Purpose Interface Bus Technical Reference," that is dated August 15th, 1984. Part number 6138155. (It wasn't called ISA, then, of course.) Subsequent to this, there were some books out (latish, but for late-comers quite good all the same) that appeared. As a supplement book to those who didn't have access to IBM's manuals (a shame), Edward Solari's books were a great help. His AT book first came out circa 1989/1990, memory serving. And then of course MindShare's multi-editions (my shelf copy here is the 3rd edition) on the ISA (and other buses.) Personally, I used the rather complete IBM information early on and liked Solari's contribution. MindShare was fine, but came too late. >and even if you knew how to >do it, the design of a card was not insignificant. Trivial, for trivial projects. I think so, anyway. Plus, IBM provided, on their proto boards, a complete, laid out 7400 series style decode section. So I guess maybe I just had it too easy. >But the biggest >hurdle for a hobbyist would be testing - you need an expendable spare >computer to test your card, because of the high risk of frying the whole >machine. These days you can get a cheap PCI bus computer for very >little, and second-hand ones for practically nothing. When ISA was the >main bus, a spare computer was a big investment. Since I do NOT consider myself to be anything other than a hobbyist in electronics -- barely that -- and since I already know just how darned easy this was for me when I knew far, far less than I do now about it, I don't know at all where you are coming from. Or, at least, I simply didn't find all the struggles you suggest. And by comparison with PCI??? No discussion. I used tools developed for PCI at Intel. I know how much they paid for them. And I know what including PCI on the Pentium did to "mom and pop" motherboard manufacturers, too. (Intel staff told me this was an internal goal, in fact.) I won't even debate it. Not worth the trouble. Jon
From: Jon Kirwan on 24 Jun 2010 04:17 On Thu, 24 Jun 2010 09:16:27 +0200, "Meindert Sprang" <ms(a)NOJUNKcustomORSPAMware.nl> wrote: >"David Brown" <david(a)westcontrol.removethisbit.com> wrote in message >news:4c23020b$0$4113$8404b019(a)news.wineasy.se... >> ISA has also always been out of the reach of the hobbyist. While there >> is no doubt that it is simpler to design an ISA card than a PCI card, in >> the days of ISA it was hard to make such a card. Information about the >> bus wasn't as easily available (no Google), and even if you knew how to >> do it, the design of a card was not insignificant. > >I designed a few cards back in the 90's. Information was not hard to come >by, Intel provided the spec, IIRC, and as long as you >double-triple-quadruple checked the power connections, the only serious >thing that could happen is that your computer locked up when the card was >inserted. And even that actually never happened to me. The hardest thing for >me was to find a decent mechanical specification to make it fit into every >computer case.. IBM provided __complete__ documentation. I always felt like I had enough. And that goes back to late 1983 and early 1984. So long before 1990, when Solari's book on the AT arrived. I did terrible things, risky things, and didn't have any trouble to speak about. Just the usual. I avoided the 'mechanicals' issue by simply using the excellent and relatively cheap (in fact, they were less expensive than 3rd-party sources [Jameco, later] which were much inferior and more expensive, to boot) IBM prototype boards. These were perfectly built, bus interface already laid out, and slick as heck to use. No troubles. And that was 1985/1986. And by that time EPROMs that were clearly fast enough for the bus were rather readily available to a meager hack like me. (BIOS extension.) Jon
From: David Brown on 24 Jun 2010 05:07 On 24/06/2010 10:11, Jon Kirwan wrote: > On Thu, 24 Jun 2010 08:57:40 +0200, David Brown > <david(a)westcontrol.removethisbit.com> wrote: > >> On 23/06/2010 23:50, Jon Kirwan wrote: >>> On Wed, 23 Jun 2010 21:04:55 +0000 (UTC), Grant Edwards >>> <invalid(a)invalid.invalid> wrote: >>> >>>> On 2010-06-23, Jon Kirwan<jonk(a)infinitefactors.org> wrote: >>>>> On Wed, 23 Jun 2010 14:13:14 +0200, "Meindert Sprang" >>>>> <ms(a)NOJUNKcustomORSPAMware.nl> wrote: >>>>> >>>>>> "Paul Keinanen"<keinanen(a)sci.fi> wrote in message >>>>>> news:9pe3269vevlnos3fn3j1ne6dv7tnfgm293(a)4ax.com... >>>>>>> At 62.5 kbit/s the bit time is 16 us, thus +/-8 us error from the >>>>>>> nominal sampling point from the middle of the bit period would be >>>>>>> allowed. >>>>>> >>>>>> Funny, all the discussions about baudrates and errors. I'd use an ISA COM >>>>>> card and simply replace the crystal... done it, works like a charm. Only 5 >>>>>> minutes work. >>>>> >>>>> Hehe. But this means you actually _have_ something with an >>>>> ISA bus on it!! These days... well. >>>> >>>> Then use a PCI card. >>>> >>>>> On your point, yes. A crystal change on any of the usual >>>>> spate of old ISA boards would easily solve the problem. >>>>> Forgotten lore. >>>> >>>> It works for PCI cards as well. >>> >>> I like ISA and simpler software. >>> >>> Although I understand reflection wave principles, clock line >>> skew and serpentine clock lines, and the like, I very much >>> appreciate being able to use simple logic, wire-wrapping >>> techniques, and custom circuit design with the ISA bus. It >>> is a low-tech bus that can be reached by hobbyists. PCI, and >>> not merely because of the hardware but also because of other >>> aspects (plug and play), out of reach of most hobbyist tools >>> and skills. >>> >> >> ISA has also always been out of the reach of the hobbyist. > > Are you just in a contrary mood, today? No other explanation > is possible. > > Out of reach??? Hardly. But I suppose it depends upon what > is, is. :) > >> While there >> is no doubt that it is simpler to design an ISA card than a PCI card, in >> the days of ISA it was hard to make such a card. > > IBM, itself (and I know this because I still have them here), > sold very cheap proto boards for the ISA bus as far back as I > can recall. Very beautiful boards, too. I believe I paid > close to $30 for each. 1984/1985. > >> Information about the >> bus wasn't as easily available (no Google), > > Hogwash. > > I still have my technical reference multi-volume binder set > from IBM with __complete__ documentation. Very complete. > Complete BIOS listings, with comments, included, and > schematics as well. I used these routinely for hobby > playing. > I suppose it all depends on what you define as "hobbyist". Finding a source for the documentation, and buying it (assuming these manuals were priced similarly to a lot of other comparable technical information) would take a lot of effort and money. It may also be as simple as you being lucky in finding these prototype boards from IBM. Imagine a hobbyist who hadn't found out about these and wanted to make an ISA card. > >> But the biggest >> hurdle for a hobbyist would be testing - you need an expendable spare >> computer to test your card, because of the high risk of frying the whole >> machine. These days you can get a cheap PCI bus computer for very >> little, and second-hand ones for practically nothing. When ISA was the >> main bus, a spare computer was a big investment. > > Since I do NOT consider myself to be anything other than a > hobbyist in electronics -- barely that -- and since I already > know just how darned easy this was for me when I knew far, > far less than I do now about it, I don't know at all where > you are coming from. Or, at least, I simply didn't find all > the struggles you suggest. > You are /far/ beyond what I would consider a hobbyist - you have a lot more knowledge and experience, and put a lot more time and money into your electronics, than I would classify as hobbyist. Amateur, perhaps (if you don't get paid for it), but I don't expect you would have difficulty getting a job as an electronics engineer. I am not saying that making an ISA board was too hard to do - merely that the investment required was at the level of "small professional" rather than "hobbyist". > And by comparison with PCI??? No discussion. > All the information about PCI that you could want is a few google searches away, as are plenty of example designs to get you started. And you can buy an Altera Max II PCI evaluation board within a hobby budget ($150), including software drivers. So playing around with PCI is certainly practical for hobbyists - though I agree that making your own PCI board is well out of reach, even for a small professional company. > I used tools developed for PCI at Intel. I know how much > they paid for them. And I know what including PCI on the > Pentium did to "mom and pop" motherboard manufacturers, too. > (Intel staff told me this was an internal goal, in fact.) > > I won't even debate it. Not worth the trouble. > > Jon
From: Jon Kirwan on 24 Jun 2010 07:11
On Thu, 24 Jun 2010 11:07:50 +0200, David Brown <david(a)westcontrol.removethisbit.com> wrote: ><snip> >Finding a source for the documentation, and buying it (assuming these >manuals were priced similarly to a lot of other comparable technical >information) would take a lot of effort and money. It wasn't hard. I'm not certain anymore, but I believe I first heard about the information either in a magazine or through the materials received when purchasing. I do remember getting a price and part number to order from IBM, by phone, and then simply writing a check and mailing it off. It wasn't a lot of money, either. Especially considering that the IBM PC/AT, 6MHz and 20Mb hard drive, was priced at $5495, memory serving. If you could find a way to peal that much out of your wallet, the manuals weren't even on the radar scope. My recollection is that the "lot of effort and money" amounted to about 1 day's effort (which I don't consider 'a lot') and the money wasn't even noticed. I didn't have to think longer than a few seconds, I believe. And when I received the material and the continuing supported updates to it, I only felt lucky that I'd taken the trouble. Never once thought about the expense of it. Must have been very small compared to the PC/AT cost, which itself was 'painful' enough to me. I am almost certain I might have not bothered, had the manual cost more than a couple hundred bucks. But I'm not sure, anymore. Just my 'sense' from memory. >It may also be as simple as you being lucky in finding these prototype >boards from IBM. Imagine a hobbyist who hadn't found out about these >and wanted to make an ISA card. When I wanted prototyping boards, the ONLY supplier ANYWHERE in the world that I could find was IBM. And I darned well knew I couldn't pony up the cost to hire a board house back then. Not then. They were WAY too expensive and my knowledge was near zero about ordering such a beast, anyway. I looked for alternatives, at the time, thinking that IBM had to be 'expensive' and that I might find less expensive alternatives. None existed that I could find. No one else had done it, yet. That came later. And when they eventually did finally arrive (from Jameco?), they were obvious garbage. So I never looked back. There was no comparison. I wasn't lucky, except for the fact that I was lucky that IBM cared enough to actually create something like this and sell it. There just wasn't anyone else around, so no choice and no luck. Anyone else actually looking and bothering to call IBM would have discovered the same thing I did, I think. They didn't hide the fact. They just didn't push it with advertising. You had to ask, that's all. Anyone sensible should have been that diligent. I don't count myself special that way. ><snip> >You are /far/ beyond what I would consider a hobbyist - you have a lot >more knowledge and experience, and put a lot more time and money into >your electronics, than I would classify as hobbyist. Amateur, perhaps >(if you don't get paid for it), but I don't expect you would have >difficulty getting a job as an electronics engineer. I've never hired out a single hour of time as an electronics engineer and don't believe I'd be competent enough to do so, either. Comprehensiveness is what is required for professional services and I can't deliver that. I know some things, but am terribly spotty elsewhere. I started out as a hobbyist and that's what I imagine I am. 'Amateur' would work about as well as a word for it, though I'm not sure there is a difference that amounts to anything. >I am not saying that making an ISA board was too hard to do - merely >that the investment required was at the level of "small professional" >rather than "hobbyist". I'm a hobbyist. Honest. >> And by comparison with PCI??? No discussion. > >All the information about PCI that you could want is a few google >searches away, as are plenty of example designs to get you started. And >you can buy an Altera Max II PCI evaluation board within a hobby budget >($150), including software drivers. So playing around with PCI is >certainly practical for hobbyists - though I agree that making your own >PCI board is well out of reach, even for a small professional company. This 'inaccessability' for even small professional companies is the center of my point. ISA is not only accessible to smaller professionals, but to hobbyists too. And wire-wrap _and_ sockets work nicely!! Jon |