Just wondering

From: Jack Peacock <peacock_at_simconv.com>
Date: Sun Mar 22 15:25:21 1998

>I remember reading a Byte article that told how to build a
computer that
>used a variant of the Z80 by Hatichi (I think that's how you
spell it).
>The computer was about the size of a lunch box. Apparently I
have misplaced
>that particular issue an was wondering if any one had it and
was willing to
>tell me where I could find the printed circuit board and the
boot disks or at
>least send me the art work and the parts list for this
particular beast.

The part is a Hitachi 64180, an improved Z80. Zilog also makes
a similar part, the Z180. I recall the article, It was from
Ciarcia's Circuit Cellar series. I think his company sold the
kits, MicroMint (?).

The 64180 was a nice improvement, made it much easier to add
DRAM to a Z80. The drawbacks were the odd pin spacing on the
DIP (70 mil centers instead of 100) and a less than perfect fit
to the newer Zilog peripherals like the SCC or CIO. I believe
the Zilog version fixed up the signal problems with cascading
interrupts and also added one more address line (to a full 1MB).

Aside from the faster clock rates and built-in peripherals, the
nicest feature of the '180s was the memory management. The CPU
had an integrated memory management unit to extend the 64K
address of a regular Z80 out to either 512K or 1M, using three
bank-switched regions.

I still have a homemade CP/M system using the 64180, 256K DRAM,
16KB EPROM, two CIOs, one SCC, a National 58167 clock calendar,
and a WD MFM hard/floppy controller card. It runs CP/M V3 and
used the MMU to access all of the 256K RAM. I built it before
Ciarcia came out with his board, chances are I would have used
his for the project instead of doing a custom card.

I keep it running for sentimental value, it was the first card I
ever designed (and got working) with dynamic RAMs.
        Jack Peacock
Received on Sun Mar 22 1998 - 15:25:21 GMT