13 Sep
1999
13 Sep
'99
5:49 a.m.
Joe writes about the HP-46:
Yes but internally it is completely different from
the 45. It uses
mainly TTL chips instead of the hybrid CMOS ones that the 45 uses.
It uses a *LOT* more ICs than the 45.
Actually, the HP-45 doesn't use hybrid chips, and it doesn't use CMOS.
It uses the same PMOS chipset as the HP-35, but with 1 Kword ROMs instead
of 256 word ROMs, and with an extra RAM chip. Some units had ROMs in
round metal can packages, and some in DIPs, but all were monolithic, not
hybrid. HP didn't use hybrid multichip modules in their first generation
handheld calculators except for the HP-80 (seven 256-word ROMs in one
hybrid, because the 1 Kword parts weren't ready yet) and the HP-65.
The HP-46 uses this chipset as well. But it adds a lot more chips to control
the printer.
HP didn't use CMOS in handheld calculators until they started offering
continuous memory in the late second generation models HP-25C and HP-29C,
and the third generation HP-33C, HP-34C, and HP-38C. By the fourth
generation (HP-41C/CV/CX, HP-10C/11C/12C/15C/16C), they used nothing but
CMOS, except for the power supply chip of the 41C, and some of the chips
in peripheral devices.
I recently was given a tour of the HP Corvallis Division, which was
specifically created as the calculator division. However, since they
no longer have anything to do with calculators, the division is mostly
responsible for inkjet cartridges. While you may think that inkjet
cartridges are simple, this tour impressed on me that actually they
are one of the most sophisticated and demanding portions of a modern
computer system. But I digress. The reason that I brought this up
is that although Corvallis Division no longer has the "Hall of Fame"
displaying every calculator model, they do still have a series of
photomicrographs in one hallway showing the evolution of the chips
that were used. Unfortunately the first photo which showed on of the
HP-35 chips is no longer there, but it was interesting to see the
others.
I didn't take a camera along, and was later told (as I'd suspected)
that I wouldn't have been allowed to bring one into the facility.
They have very tight security, and apparently it was a fairly
uncommon occurance that my host was able to obtain a visitor pass for
me (and on only a few hours advance notice). He said that some of
his acquaintances who've asked for tours have had to wait months.
Eric