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Thread: Cable Driver/Line Driver/Buffer IC advice request. ;-)


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Trash80toHP_Mini

Posts: 45
Registered: 10/19/12
Cable Driver/Line Driver/Buffer IC advice request. ;-)
Posted: Dec 20, 2016 10:44 AM
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I need a little help on a problem I'm having for an approach I think I'm probably overthinking . . . I think . . . :-/

I really don't do electronics, it's more along the lines of electron plumbing and I need help identifying what type hose-splitter connection I need to maintain a logical high signal tap from the IIsi host's single NuBus Adapter's connector across a four pin spread feeding two NuBus Slots on the proposed 2 NuBus Slot Adapter I'm developing for the IIsi.

Easiest thing is probably to check out the diagrams in my topic over at the MLA: ;-)Cable Driver/Line Driver/Buffer IC advoce request.

Here's the link to the overall project: TWO SLOT IIsi Nubus Card hack . . . Take 2

The reason for the SE/30 tag is that this little IIsi hack, a project with its own merit in my SuperIIsi™ build, is the first stepping stone toward: Project30 adapting the IIsi NuBus adapter to a twin slot NuBus implementation on the SE/30's PDS.

The reason I'm tempted into to takig this so far over the top is that I'd like to be able to use this modified DuoDock Gemini Card with a jumper based Slot ID playground is pure curiosity. Things like finding out if the IIcx can address Slots $B, $D and $E which were lopped off when the chopped the IIcx in half to fit into the cute little case that became home to the ubiquitous IIci. It also would be fun pasting that third NuBus Slot back into the Quadra 700 from which it was cut. That one would be a testbed only experiment, only the IIsi's case/backplane configuration makes this idiocy practical within one of Apple's boxen.

__________________________________________________________________________________

My limited understanding of the Mac's logical HIGH would be initiated by current from a resistor (spec on one of those would also be greatly appreciated) feeding something close to 5V to the Slot ID pins on NuBus. Logical LOW appears to be a direct connection to GROUND.

If anyone could explain this to me or flesh it out in any way I would greatly appreciate it. I've got some grounding in the flow of logical circuits from studying Don Lancaster's wonderful CMOS Cookbook, but I lack knowledge of the basic principals of feeding and directing power to that wonderfully complex irrigation system.

p.s. looks like I might have needed to add OP AMP to my list? Dunno, I just play with tools on whatever stuff I find laying around r snag out of curiosity. Wood, metal, Plexi and my palette of Acrylics would be my favorites, which is why I need to ask for help on the basics of electronics from you folks. So many projects, so little time and way too much distraction.

THX much for any help.

Merry Christmas, Happy Hanukkah and Happy New Year, gang!
jt


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