> Most of the chips are RCA, 5 are Mostek, and 2 are marked:
> A*
> MI
AMI, American Microsystems
Almost all of the early HP PMOS calculator chips were fabbed by
either Mostek and AMI. They are custom for HP, so don't bother
looking in catalogs.
> From first look the CPU seams to hafe a serial architecture.
Yes. There is a two-phase clock and synchronization signal to
denote that start of a 56-clock cycle. There is a data line which
is used to transfer a 56-bit word to or from memory and peripherals
each cycle, although most cycles it is not actually used. There
is a line that the CPU uses to shift out an 8-bit instruction address
to ROM (addressing beyond 256 words is by bank-switching), and a line
that the ROM uses to send back a 10-bit instruction.
For more details, check out my web site:
http://www.brouhaha.com/~eric/hpcalc/
I've written a complete microinstruction-level simulator of the HP-45
which is available there.
Eric
Received on Mon Sep 13 1999 - 12:57:04 BST