Intel 8085 on the S100 Bus

[SwedaGuy]

I have found various specifications for using the S100 bus for a single-board computer running the Intel 8080 or Zilog Z80 processors (think Altair/Imsai), but I would like to know if there is a specification for the extra signals on the Intel 8085 processor, namely Restart 5.5, Restart 6.5, Restart 7.5 and TRAP.

There are vectored interrupt lines in the S100 spec, but I've only seen them used to interface to an 8214 Priority Interrupt Control IC.

Should I stop being picky and just use four vacant lines, or is there an established standard for this?

Also, any great sources for a few S100 backplanes? I don't need a 20 slot, but a 4 slot would probably not be enough--so somewhere in the middle would be good. I intend to have Protocase build me the cases for this project.

Input is appreciated, thanks!

[lynchaj]

SwedaGuy,

I do not have any great suggestions at this time but I do have some S-100 books on order. When they arrive I will look them up and see what they say on the subject. If you find the answer to your question, I would certainly like to hear what it is so please post it.

Have you tried looking at the IEEE-696 standard? Maybe they address it there?

Best of luck!

Andrew Lynch

[Terry Yager]

I'd agree. If 696 does not specify, make do with what's available, but at the possible expense of compatibility with other devices/systems/software/etc. Might be better to not use the extra signals unless you absolutely have to.

BTW, I've just scanned thru Z-100 manual, but nothing useful there.

You might try poking around here for some ideas/schematics, etc. http://www.pestingers.net/HZ100_man.htm

It's a problem that may have been solved already, as the Z-100 interfaces an 8085 to the S-100 bus.

--T

[Terry Yager]

Here's a link to Herb Johnson's page comparing various flavors of S-100:

http://retrotechnology.com/herbs_stuff/s100bus.html

--T

[SwedaGuy]

Thanks for your input on this...

I'll check out that 696 standard to see if it offers any insights.

I've knocked around Herb's website before, and he's got a lot of information. That other site is new to me, however, and I think I'll be spending some time there today...

Thanks!
Dylan