Date : Thu, 30 Apr 1987 06:36:00 MDT
From : Keith Petersen <W8SDZ@SIMTEL20.ARPA>
Subject: Z280 - run 8-bit CP/M at twice IBM-AT speed
From GEnie's CP/M RoundTable:
Category 2, Topic 34
Message 2 Sun Apr 12, 1987
B.DUERR [Bill] (Forwarded)
Zilog finally does it--the Z280 is here! It's what the original
Z800 was said to be and more. The Z800 has been rumored for four years
now as a super chip that is still compatible with the Z80. The chip is
an extension of a Z80, much more so than the HD64180.
The Z280 runs all Z80 instructions (and therefore all 8080
instructions) and includes an expanded set of 45 new instructions plus
additional addressing modes. It has both 8-bit and 16-bit signed and
unsigned multiply and divide instructions. The set has over 600
instructions. At clock rates of 10 megahertz and above, 16-megabytes of
memory address space, and 8-bit Z80 bus or 16-bit Zilog Z-Bus,
capabilities far exceed Intel's 80286 used in IBM PC AT. Addressing
modes offered make high-level languages more effective than ever. Using
the Z-Bus, an extended Z80 instruction set is available and a CPU that
is true 16-bit, as is the 80286. The Zilog Z280 is a highly integrated
CPU, major functions are a paged memory-management unit with a 256-byte
data and instruction cache, three-stage instruction pipelining, a
four-channel DMA controller, three 16-bit counter/timers, a six-stage
wait-state generator, a DRAM refresh controller, and a high-speed UART
with rates up to 2.5 mHz.
Category 2, Topic 34
Message 3 Sun Apr 12, 1987
B.DUERR [Bill] (Forwarded)
High Tech Research is planning to use the Zilog Z280 in their
"Ultraboard", an add-on board for all '84 Series CP/M Kaypros including
the 10-83. The High Tech Research Ultraboard is now in beta-testing for
a summer release and has a target price of less than $500.
You will be able take the cover off your CP/M Kaypro, unplug the
Z80 chip, plug the Ultraboard into the Z80 chip socket, attach the
Kaypro monitor cable to the Ultraboard, and your CP/M Kaypro will run
with a processing speed of 12MHz, up from its' current 4MHz, with an
effective throughput up to 10 times that of a normal CP/M Kaypro in
situations that aren't I/O bound (limited by disk access speed, etc.).
It will come with 1 megabyte of RAM, expandable to 16 megabytes,
configurable as a RAM disk by the user. You will be able to choose your
own foreground and background hues on an external RGB color monitor.
The board supports Virtual Memory and Cache Memory.
The Ultraboard's Z280 on-board Cache Memory automatically stores
all recently used instructions and/or data, so the processor has instant
access to them for memory fetches, and subsequent disk and memory
accesses are eliminated. On chip Cache Memory can reduce bus
transactions by a much as 75%. Its Instruction Pipeline functions like
three co-processors built into a single chip, internally processing
multiple instructions. As the first processor is handling one
instruction, processors two and three are simultaneously working on the
next two instructions. Pipelining contributes dramatically to the
Ultraboard's improved processing speed.
High Tech Research had to replace the Kaypro screen driver so the
screen could keep up with the Z280's processing speed. The Ultraboard
includes a new 18MHz no-wait-state graphics screen driver, with its own
256 byte Cache Memory for instantaneous screen updates, 25 times faster
than your current screen. No more waiting for the screen to catch up
with your programs.
The new screen driver comes with an RGB connector so you can attach
an external color monitor to your Kaypro and select your own display
colors. You can even design your own character sets, and switch between
them and the standard Kaypro character set. The graphics chip set (GKS)
on the Ultraboard contains a subset of the new GKS Standard.
The Ultraboard supports multi-tasking and networking. But like the
286 and 386 processors, full realization of these Ultraboard
capabilities awaits the completion of an operating system, already under
development, specific to the new processor.
A power kit supplies continuous backup battery power to the RAM, to
keep the memory capacity of the machine always active, during a cold
boot, a power failure, or even when the computer is turned off. The
Ultraboard provides pin-outs for an SCSI bus, enabling the processor to
support up to 300 megabytes of hard disk storage. The package will
include enhanced version of Handyman, which will remove the 8K limit on
notepad, for example.
High Tech Research has in development a high speed interface
between the Ultraboard and the PC. This will eventually permit the
connection of the CP/M Kaypro to a cheap PC clone for hard disk storage,
and for use as a network file server.
As far as pure speed goes, the Ultraboard should be at least
comparable to a standard AT. The real question is whether there will be
any software written to take advantage of it. Standard CP/M software
should run but won't take advantage of the extra memory, which will have
to be used as a RAM disk. High Tech is in contact with some people who
are interested in converting programs to the new chip. Depending on how
the chip itself handles the extra memory, it might be easy to convert a
program to look for RAM beyond 64K and use it if found.
Category 2, Topic 34
Message 4 Mon Apr 20, 1987
B.DUERR [Bill] (Forwarded)
For more information on the Zilog Z280 chip, contact Jim Magill,
Richard Davies, or Tom Hampton, Product and Technical Marketing, Zilog,
Inc., 210 Hacienda Ave., Campbell, CA 95008, 408/370-8000 or 370-5166.
For more information on the Ultraboard contact High Tech Research, 1135
Pine Street, #107, Redding, CA 96001, (800)446-3220, (800)446-3223 in
California.