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From: Jon Kirwan on 23 Jun 2010 17:01 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. I keep an older 80386DX and 80486DX machine around (three, actually) all nicely sporting lots of ISA slots. Also have proto ISA boards I can use to slap up an easy custom circuit on. No way could do that with PCI. My 80486DX boots up Win98SE at 33MHZ and 64Mb RAM (with an external cache made from discrete static rams) faster than my WinXP boots on a 2.94GHz cpu. I actually prefer to use it, too. On your point, yes. A crystal change on any of the usual spate of old ISA boards would easily solve the problem. Forgotten lore. Jon
From: Grant Edwards on 23 Jun 2010 17:04 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. -- Grant Edwards grant.b.edwards Yow! An Italian is COMBING at his hair in suburban DES gmail.com MOINES!
From: Jon Kirwan on 23 Jun 2010 17:50 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. And I also understand the desire to get rid of the south bridge, chipset side-band channels to support ISA DMA over a bus that simply cannot and does not support ISA DMA timing requirements, interrupt mapping, and so on. It's pretty obvious this was a huge source of continuing chipset bugs and needed testing regimes, as well. But I like ISA. Jon
From: Grant Edwards on 23 Jun 2010 17:58 On 2010-06-23, Jon Kirwan <jonk(a)infinitefactors.org> wrote: > On Wed, 23 Jun 2010 21:04:55 +0000 (UTC), Grant Edwards >>>>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 swapping out the buad-rate clock oscillator on a PCI serial card requires no understanding of any of that. > 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. We're not talking about building a card from scratch. We're talking about taking an off-the-shelf serial card and swapping out the xtal oscillator. > 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. Swapping in a 2.00MHz oscillator for a 1.843MHz oscillator on a PCI card requires _exactly_the_same_ skills as doing it on an ISA card. > And I also understand the desire to get rid of the south bridge, > chipset side-band channels to support ISA DMA over a bus that simply > cannot and does not support ISA DMA timing requirements, interrupt > mapping, and so on. It's pretty obvious this was a huge source of > continuing chipset bugs and needed testing regimes, as well. I have absolutely no idea what any of that has to do with this thread. -- Grant Edwards grant.b.edwards Yow! Mary Tyler Moore's at SEVENTH HUSBAND is wearing gmail.com my DACRON TANK TOP in a cheap hotel in HONOLULU!
From: Jon Kirwan on 23 Jun 2010 18:07
On Wed, 23 Jun 2010 21:58:21 +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 21:04:55 +0000 (UTC), Grant Edwards > >>>>>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 swapping out the buad-rate clock oscillator on a PCI serial card >requires no understanding of any of that. Agreed. I just took Meindert's comment regarding an ISA board and ran with it. :P >> 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. > >We're not talking about building a card from scratch. We're talking >about taking an off-the-shelf serial card and swapping out the xtal >oscillator. We could be, but I expanded Meindert's comments in a different direction for the pure pleasure of doing so. Threads are sometimes like that. >> 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. > >Swapping in a 2.00MHz oscillator for a 1.843MHz oscillator on a PCI >card requires _exactly_the_same_ skills as doing it on an ISA card. 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 (and the tool tips required, too.) It _may_ be the case, but not necessarily so as these two boards easily illustrate to me. >> And I also understand the desire to get rid of the south bridge, >> chipset side-band channels to support ISA DMA over a bus that simply >> cannot and does not support ISA DMA timing requirements, interrupt >> mapping, and so on. It's pretty obvious this was a huge source of >> continuing chipset bugs and needed testing regimes, as well. > >I have absolutely no idea what any of that has to do with this thread. Then you are lost to what I've been saying. Which is fine. That happens, as well. Jon |