Re: Z180 (was: Captain Video)
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I got my TI-86 in 1998 or maybe 1999. So I don't think it would be considered "later" but can't swear to it. It did use a different processor from most of the other graphing calculators they sold. I'm one of those math-deficient types, and was a poor starving student with 3 kids when I got it, as it was the cheapest TI graphing calculator at the time. Wife got a TI-89 a couple of years later, and it was not compatible at all with the TI-86. My girls got TI's with color screens when they were old enough, and that was between 2014 & 2016 for oldest and youngest, respectively. Don't remember which models they got, though. I was already an ex-teacher by then, and not doing anything but email & social media by then. Now I'm retired again, and got a little time to play. New machine has shipped, no tracking. We'll see how it goes.?
Bill in OKC
William R. Meyers, MSgt, USAF(Ret.)
A human being should be able to change a diaper, plan an invasion,
butcher a hog, conn a ship, design a building, write a sonnet, balance
accounts, build a wall, set a bone, comfort the dying, take orders,
give orders, cooperate, act alone, solve equations, analyze a new
problem, pitch manure, program a computer, cook a tasty meal, fight
efficiently, die gallantly. Specialization is for insects.
LAZARUS LONG (Robert A. Heinlein)
On Wednesday, August 5, 2020, 02:53:50 PM CDT, ajparent1/kb1gmx <kb1gmx@...> wrote:
Many of the later TI 8x were not true Z80 but the sorta compatible Rabbit.
and I think later eZ80.
A good example of bus width is the DEC T-11, its PDP11 a 16 bit architecture
but the T-11 had a feature (at reset) that could make it do two bus fetches
on an 8bit bus for a speed cost but system simplicity.? The Z280 also could
do that.
The 8088 and 8086 were software identical save for bus width, s the 8088?
was slow due to the need for multiple bus fetches and IBM ran it slow?
(4.77mhz seriously?) cheaper 5mhz part and slow cheap memory.?
Before that system fully emerged I was running a?8mhz 8086?on
Multibus CP/M-86 and it did scream.? By 1983 there were 12mhz
8088 systems out there.? Fast enough to make an appearance.
PC were interesting but the clone wars forced improvement and
compatibility.? ?One of the hybrid system Is the compupro 8085 at
12mhz and 8088 at 12 or 16 mhz for a late 1983 board.? It was
either cpu only with one cpu was running but switching on the fly
back and forth was possible.
The last kicker was the NEC upd72108 V20, it was 8088 and thee was
the 16bit 8086 version too. software compatable with 8088/6 with speedup
and a 8080 emulation mode.? Very popular as it was 5-10% faster for the
same clock.? It was one of the compatable but not identical or from
intel/AMD masks.? I still have a few of the 8mhz parts and a few screened
for 12.
As to market over engineering [8088] well sorta. most of us viewed it as
a 8085 with a bag on the side and the segmentation scheme was totally
nuts.? The PC had many legacy issues follow it into the days of Pentium
due to that.? It was dominant and far from good.? The?68000, Z8000,
and then later MIPS, ARM, Power PC were all better but some were
late or too buggy early on.
The goals came from the super minis.? Large address space at least
16bit registers, efficient byte/word handling and extended math,
coupled to directly address large address spaces with memory protection.
IT was driven by the ability to put 16 and even 32bits on a single chip.
That and the price of memory dropping from about 100$ for 16k bytes
in 1980 to about that for 1MB by 1985 and 16mb by 1989.
Z180/64180 is attractive and did fill a large part of the embedded systems?
space before the later chips got cheap enough in the late 90s.? I have an
old GPS that has a Z180 in it
I left out the TI9900 as it was true 16bit but slower than glacial.?
By 9900 I mean the 9900, not the later 9980 or 9985 8bit bus
crippled versions.
Allison
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Bill in OKC too