27 Jan
2011
27 Jan
'11
2:29 p.m.
Chuck wrote:
Would you consider the MC14500 to be a
"computer"?
Tony wrote:
More seriously, from what you say, I think I would
consider it a computer
in some applications but maybe not in all.
Note that the MC14500B did not contain a program counter. It was really
just a one-bit ALU with a small amount of logic to interface to an
external sequencer. That sequencer could simply be a binary counter, if
you didn't need branching, or it could be something elaborate with a
subroutine stack. The MC14500B Industrial Control Unit Handbook gives
an example using three Fairchild Macrologic CMOS 34706 control sequencer
bit slices, which are conceptually similar to the Am2909/2911.
(Motorola doesn't mention Fairchild by name, and it took me a while to
figure out what they were, because at some point Fairchild changed the
part number from 34706 to just 4706.)
Eric