Date   : Mon, 14 Dec 1987 17:02:47 GMT
From   : hp-pcd!uoregon!omepd!mipos3!cadev4!dbraun@hplabs.hp.com (Doug Braun ~)
Subject: What is the Z-280 (People have asked)

People have asked me what the Z-280 is, so here is a description:

The Z-280 is a new Z-80 compatible chip from Zilog.

It includes:
       Enhanced instructions including 16-bit signed and unsigned
       multiply and divide.

       Many new addressing modes for most instructions, including
       16-bit indexed, stack pointer relative, pc relative, and
       base-indexed.

       On-chip peripherals: One serial port, 4-DMAs, 3 counter timers.

       Paged memory management, supporting virtual memory and
       seperated code and data space.

       User and system modes, allowing 'illegal opcode' traps
       for things like I/O in user mode.

       A 256-byte cache.

       Configurable for a 16-bit bus interface with to do burst
       reads (4 words in one bus cycle).


This is a very sophisticated chip.  With a 16-bit bus and burst memory,
you shopuld get about 5x speedup, as far as I can tell.
With an inproved compiler for the new instructions, even more
speedup will result.  The chip has been available for several months;
single unit price is about $40.
It blows away the Hitachi HD61480 chip, which is also a Z-80 enhancement.
That chip has virtually no added instructions, no new addressing modes,
crude memory management, no protection, and the same old Z-80 bus interface.

By the way, the Z-280 will also run with the standard Z-80 bus, as well
as the 16-bit bus.


Doug Braun                             Intel Corp CAD
                                       408 496-5939

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Doug Braun                             Intel Corp CAD
                                       408 496-5939

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