Greetings! I was initially planning on setting up my mid-late 70's 8080 computer on wire-wrapped S-100 boards. However, I found that S-100 prototype boards are very expensive. Bill Dudley suggested I use a standalone prototype board that he had, but it has limited real estate for things like memory and disk control circuitry. It has an expansion connector, but it is a proprietary connector. After some research, I think I may have found the solution: Intel's Multibus. For one thing, wire wrap prototyping boards have more area and are readily available (and inexpensive.) A multibus power supply puts out standard voltages which do not require regulators on each card. Is this the ideal solution that I'm thinking it is, or am I overlooking something? TIA Joe Giliberti
Hi Joe, I can understand if you want to take a different route but the S-100 prototype boards I pointed to earlier are quality boards at $25 each. The inventory is shown at the link below after scrolling down to the S-100 section. Todd’s contact info is located near the bottom of page. https://www.retrobrewcomputers.org/doku.php?id=boardinventory On Thu, Jan 13, 2022 at 12:13 AM Joseph Giliberti via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:
Greetings! I was initially planning on setting up my mid-late 70's 8080 computer on wire-wrapped S-100 boards. However, I found that S-100 prototype boards are very expensive.
That's odd. I didn't see your message for some reason. I was mainly basing my decision on the NOS boards on ebay which sell for $75. Maybe the bus will reverse course On Thu, Jan 13, 2022 at 2:53 AM Jeff Galinat <jgalinat@gmail.com> wrote:
Hi Joe, I can understand if you want to take a different route but the S-100 prototype boards I pointed to earlier are quality boards at $25 each.
The inventory is shown at the link below after scrolling down to the S-100 section. Todd’s contact info is located near the bottom of page.
https://www.retrobrewcomputers.org/doku.php?id=boardinventory
On Thu, Jan 13, 2022 at 12:13 AM Joseph Giliberti via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:
Greetings! I was initially planning on setting up my mid-late 70's 8080 computer on wire-wrapped S-100 boards. However, I found that S-100 prototype boards are very expensive.
On Thu, Jan 13, 2022 at 02:12:05AM -0500, Joseph Giliberti via vcf-midatlantic wrote:
After some research, I think I may have found the solution: Intel's Multibus. For one thing, wire wrap prototyping boards have more area and are readily available (and inexpensive.) A Multibus power supply puts out standard voltages which do not require regulators on each card.
Is this the ideal solution that I'm thinking it is, or am I overlooking something?
Multibus seems to be the fringe of vintage computing now but was a popular bus in the past. From my perspective it was more popular with industrial/embedded systems. S-100 was more business/home. I did a couple cards for it before we switched to VMEbus. We did some complex multi processor systems with it for radar simulators among other things. It was long enough ago details a fuzzy but my memory is it wasn't that hard to implement the interface. Multibus will allow you to explore an interesting corner of vintage computing that isn't getting that much attention. S-100 your going to find more people who can help if you have questions/problems since its more active now. I think I have an old Multibus bus probe that was uses for troubleshooting I could loan if you don't have more modern equipment that would be better or just want to play with it.
It was long enough ago details a fuzzy but my memory is it wasn't that hard to implement the interface.
It's definitely more complicated than S-100, though. I don't believe it's required for basic operation, but Multibus has greater multi-master (DMA) support and is significantly better designed than S-100. You do also have the "do whatever on the P2 connector" factor, if you're wanting compatibility with other boards. I probably wouldn't recommend Multibus for a first-time project...or really any bus for that matter. If this is the very first computer you've designed and built by hand, do it on a big chunk of protoboard as a single-board computer. Perhaps even hold off on floppy disk support and whatnot and just wire up a "trainer" type board: CPU, ROM, some quantity of ram, serial port, parallel port, and that's it. You'll learn a lot that will prepare you to learn a lot more when you go to do a full-featured system! Thanks, Jonathan
On Thu, Jan 13, 2022 at 9:25 AM Jonathan Chapman via vcf-midatlantic < vcf-midatlantic@lists.vcfed.org> wrote:
It was long enough ago details a fuzzy but my memory is it wasn't that hard to implement the interface.
It's definitely more complicated than S-100, though. I don't believe it's required for basic operation, but Multibus has greater multi-master (DMA) support and is significantly better designed than S-100. You do also have the "do whatever on the P2 connector" factor, if you're wanting compatibility with other boards.
I probably wouldn't recommend Multibus for a first-time project...or really any bus for that matter. If this is the very first computer you've designed and built by hand, do it on a big chunk of protoboard as a single-board computer. Perhaps even hold off on floppy disk support and whatnot and just wire up a "trainer" type board: CPU, ROM, some quantity of ram, serial port, parallel port, and that's it. You'll learn a lot that will prepare you to learn a lot more when you go to do a full-featured system!
Thanks, Jonathan
Hey Joe, I have a working Multibus system at the shop in Kennett Square if you want to at least see one in action. I like the idea of building a 6502 single board computer for a first project, but if you want to go S-100 then personally I'd start with a set of known-working kit boards (assuming you solder everything correctly) that you can experiment with as you build. You can buy these from hobbyists who sell them and who offer support/manuals. This way you'll have an end point to the project that you can measure and perfect. You can build and test as you go, and get that experience under your belt and then replace each S-100 board one at a time from your own scratch design. I am not an engineer, I have never designed and built an S-100 system from scratch, but I have done a few kits successfully. BIll Degnan kennettclassic.com
On 1/13/22 9:24 AM, Jonathan Chapman via vcf-midatlantic wrote:
I probably wouldn't recommend Multibus for a first-time project...or really any bus for that matter. If this is the very first computer you've designed and built by hand, do it on a big chunk of protoboard as a single-board computer. Perhaps even hold off on floppy disk support and whatnot and just wire up a "trainer" type board: CPU, ROM, some quantity of ram, serial port, parallel port, and that's it. You'll learn a lot that will prepare you to learn a lot more when you go to do a full-featured system!
Being that Joe wants to stay in the ~1997 timeframe, Steve Ciarcia's "Build Your Own Z80 Computer" book would be a very good place to start. -Dave -- Dave McGuire, AK4HZ New Kensington, PA
participants (6)
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Bill Degnan -
Dave McGuire -
David Gesswein -
Jeff Galinat -
Jonathan Chapman -
Joseph Giliberti