30 Mar
2011
30 Mar
'11
11:09 a.m.
The Steve Ciarcia "Micromint"? PC used a terminal as it's default console.
Its BIOS and/or I/O drivers might help as a starting point.
But, because a significant portion of their users actually wanted a "real"
5150, they came out with an ISA board for it with a 5150 style keyboard
interface. Studying that might help with building an S100 imitation of
the 5150 keyboard interface.
Unlike the PC/AT (5170) and later machines, the 5150 (PC) (and thus the
5160 (XT)) keyboard interfaces did not use a custom-programmed
microcotnroller at the motherboard end. Insted, the 5150/5160 used a TTL
shidt register (74LS323 I think), and a bit of supporting logic. It was
linked to the ports of an 8255 chip. The schematics are in the TechRef,
of course, and since there are no programmed parts involved, that's all
you would need to recreate it.
-tony