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+--- Thread: System 80 X-4020 Expander KiCAD woes (/thread-623.html)
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RE: System 80 X-4020 Expander KiCAD woes - RedskullDC - 22-02-2023
(22-02-2023, 11:22 AM)CheshireNoir Wrote: Cheers RedskullDC.
If I can find a 1771 variant that doesn't need +12V and -5V, then I'll stick with that. I was looking at the 1770, which seems to have a single density toggle.
(That's a long way down the road tho. Wanna get the RAM plumbed in first.)
John
Hi John,
All good.
1770 is basically the same as the 1772, but the 1772 has faster track stepping rates.
Be aware that the 1771 can produce "4 different data address marks", whilst the others can only produce/read *two*.
From memory, most of the DOSes which also appear on the Model3 only use the 2 DAMs which the 1791 (and later) chips can produce.
Cheers,
Leslie
RE: System 80 X-4020 Expander KiCAD woes - CheshireNoir - 23-03-2023
If anyone is interested in a copy of the original schematics, converted to KiCAD, I've uploaded them to GitHub.
Get at 'em. Have some fun!
https://github.com/cheshirenoir/X4020Expander
John
RE: System 80 X-4020 Expander KiCAD woes - ChickenMan - 13-04-2023
Thanks John, will also put them in the System 80 Repository in the Vintage\System-80\Documentation\Schematics folder.
RE: System 80 X-4020 Expander KiCAD woes - CheshireNoir - 13-04-2023
Thanks ChickenMan.
Hopefully they'll be helpful to someone in the future. I haven't got much further with "modernising" the design
My skills at designing PCBs is not backed by any particular skills at designing schematics, unfortunately.
John
RE: System 80 X-4020 Expander KiCAD woes - IBM Portable PC - 12-06-2024
Why not the unbelievably rare X-4010?
Surely the S-100 interface makes this expansion box more interesting to many people?