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From: Jon Kirwan on 24 Jun 2010 19:32 On Thu, 24 Jun 2010 15:35:04 +0200, David Brown <david(a)westcontrol.removethisbit.com> wrote: >On 24/06/2010 13:11, Jon Kirwan wrote: >> 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. > >I guess it is this more than anything else that puts ISA out of the >range of hobbyists to my mind - you don't mess around with putting >home-made cards into a $5500 computer unless you are happy to risk >damaging it, or you are /very/ confident of your abilities. Either way, >you are not a hobbyist. Oh, cripes. I have nearly destroyed a _new_ $2,000 piece of equipment back around that time merely because I hadn't realized that the ground plug on one properly designed piece of test equipment I was using might cause a hot-side short to the IBM Model 85 electronic typewriter which didn't have such a plug and was plugged in reverse-wise. Nicely destroyed a power supply board, which I had to repair. There is no question I was barely a hobbyist, if that, at the time. And yes, I was willing to take risks with my money because I wanted to learn, too. I did what I knew to do to avoid throwing money in the dumpster or killing myself, but I'm quite certain I didn't do as much as those smarter than me did. I made plenty of mistakes as I went. And I have had zero formal training here, by the way. Even to this day. I don't know why you want to imagine I'm something I know I'm not. But there it is. >Hobbyists who wanted to connect a card to a PC gave them an RS-232 >interface or a parallel port connection - just like these days they give >them a USB connection or an Ethernet port (or possibly a RS-232 connection). I used those, too. For example, in the above typewriter case I was scoping out the reed relay signals so that I could figure out how to turn it into a printer. I then designed and programmed by own 8031 board, with EPROM, and rat-nest wired the thing across the reed relays and brought out a ribbon cable to the tiny proto box I had. There, I used 1488 and 1489 level shifters with the 80C31 and a serial port to the PC for use as a printer. Worked first time (after fixing that power supply board in the electronic typewriter that I'd wrecked.) But this was almost around the same time when I also did my first proto board that plugged directly into that $5500 PC/AT. And I was barely any smarter at that point and nearly as likely to destroy something there, too. You learn by screwing up and then reinforce the stuff you did learn well, by succeeding. And I'm still a hobbyist. Jon
From: Fred on 25 Jun 2010 00:27 Last time on comp.arch.embedded, Jon Kirwan <jonk(a)infinitefactors.org> said: >>If possible I'd like it to run at a non-standard baud rate (62,500 baud). > >I'm not sure an IBM PC uart can run at that rate. It could if you're willing to change the crystal on the UART card...
From: Jon Kirwan on 25 Jun 2010 07:02 On Thu, 24 Jun 2010 21:27:15 -0700, Fred <fuque(a)hotmail.com> wrote: >Last time on comp.arch.embedded, Jon Kirwan <jonk(a)infinitefactors.org> >said: > >>>If possible I'd like it to run at a non-standard baud rate (62,500 baud). >> >>I'm not sure an IBM PC uart can run at that rate. > >It could if you're willing to change the crystal on the UART card... Yeah. I think that has been mentioned in this thread about... 20 times already? And have you actually done this on a modern PC? In any case, I haven't looked recently, but few PCs these days seem to sport RS-232 or RS-485 ports. For those that may, high integration on the board may not make it it so easy. I believe the ones old enough to actually have a south bridge probably use a super I/O chip or have it integrated into the south bridge along with the APIC and perhaps have some divider used to get the "pc standard" rates created. It all has to look like an ISA dohicky or old software won't work right. PCI boards also exist and they have drivers that are probably Windows-standard, too, but then that is a whole other thing to worry about and I'm not sure how the WinOldAp or NTVDM emulates the old chips into the DOS boxes. It's been a long time since I looked, but unless I heard directly from someone who has achieved this with a new PC system, I'd be skeptical of a claim about it being easy to do. Maybe someone has and can fill us in about it. Jon
From: Fred on 26 Jun 2010 01:15 Last time on comp.arch.embedded, Jon Kirwan <jonk(a)infinitefactors.org> said: >On Thu, 24 Jun 2010 21:27:15 -0700, Fred <fuque(a)hotmail.com> >wrote: > >>Last time on comp.arch.embedded, Jon Kirwan <jonk(a)infinitefactors.org> >>said: >> >>>>If possible I'd like it to run at a non-standard baud rate (62,500 baud). >>> >>>I'm not sure an IBM PC uart can run at that rate. >> >>It could if you're willing to change the crystal on the UART card... > >Yeah. I think that has been mentioned in this thread >about... 20 times already? I only saw one other mention; somehow I missed the other 19. >And have you actually done this on a modern PC? Not on a PC motherboard, but I have done it on an expansion card. >In any case, I haven't looked recently, but few PCs these >days seem to sport RS-232 or RS-485 ports. Just the other day I bought a 2-port RS-232 PCI expansion card. Cost me $17 at a local retail store, but you can get the same card online for ~$12. >It's been a long time since I looked, but unless I heard >directly from someone who has achieved this with a new PC >system, I'd be skeptical of a claim about it being easy to >do. > >Maybe someone has and can fill us in about it. The card I just bought has a normal-looking, through-hole-mounted crystal on it. Even a software guy like me could swap it out.
From: Jon Kirwan on 26 Jun 2010 04:01
On Fri, 25 Jun 2010 22:15:39 -0700, Fred <fuque(a)hotmail.com> wrote: >Last time on comp.arch.embedded, Jon Kirwan <jonk(a)infinitefactors.org> >said: > >>On Thu, 24 Jun 2010 21:27:15 -0700, Fred <fuque(a)hotmail.com> >>wrote: >> >>>Last time on comp.arch.embedded, Jon Kirwan <jonk(a)infinitefactors.org> >>>said: >>> >>>>>If possible I'd like it to run at a non-standard baud rate (62,500 baud). >>>> >>>>I'm not sure an IBM PC uart can run at that rate. >>> >>>It could if you're willing to change the crystal on the UART card... >> >>Yeah. I think that has been mentioned in this thread >>about... 20 times already? > >I only saw one other mention; somehow I missed the other 19. I believe I saw several different people mention the possibility and more still accepting the point and referring to it. >>And have you actually done this on a modern PC? > >Not on a PC motherboard, but I have done it on an expansion card. The comment of mine that you quoted was "I'm not sure an IBM PC uart can run at that rate." Note that I wasn't discussing expansion cards. >>In any case, I haven't looked recently, but few PCs these >>days seem to sport RS-232 or RS-485 ports. > >Just the other day I bought a 2-port RS-232 PCI expansion card. Cost >me $17 at a local retail store, but you can get the same card online >for ~$12. I wasn't discussing expansion cards. >>It's been a long time since I looked, but unless I heard >>directly from someone who has achieved this with a new PC >>system, I'd be skeptical of a claim about it being easy to >>do. >> >>Maybe someone has and can fill us in about it. > >The card I just bought has a normal-looking, through-hole-mounted >crystal on it. Even a software guy like me could swap it out. I wasn't discussing expansion cards. Jon |