Building your own Z80 / performance

From: Thomas Poff <thomas_at_0000000.com>
Date: Thu Oct 22 12:25:14 1998

Hi,

I have never tho't of the Z80 as a slow processor. I interfaced a Z180
running at 18 mhz to a VGA board recently and using a C compiler was able to
build a machine that acted essentially like a 80286 running at 10 mhz. The
system was compact and inexpensive, with lots of i/o options and such. A Z80
running at 200 mhz would be a phenomenal performer.

If you have cash, you can find Z80 cores in verilog these days. A Z80 with
MMU (a la Z180) rounds out to about 8k gates in logic. This being the case,
you can fit it into a single FPGA with lotsuv room to spare. You could
prototype in Verilog on an FPGA and turn a few custom chips if that's what
you want.

Z80 is a pretty cool platform for building an extremely cheap and modern
network computer since it acts a lot like a 16 bit processor. There's a lot
you can do with it with a relatively minimal effort.

Why not look at doing your own Z80 in a Xilinx or Altera part? Obviously
you can't get 200 mhz out of it unless you turn your own chip but you can get
all of the flexibility you want in a fairly fast processor. Producing a
custom chip is expensive but may be your only option if you want that
ultra-fast Z80.

Incidentally, these guys (see link below) have a board anyone can use for
learning and building a Z80 on an FPGA. They have a board with a 20,000 gate
FPGA for about $350 that looks interesting enough to get started on. I
believe you can also gang them up in parallel for any weird projects you
might have in mind. Keep in mind that because of routing issues, not all
20,000 gates are usable in a design.

http://www.xess.com
(click on other products)

----
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Date: Thu, 22 Oct 1998 09:45:58 -0500
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From: Arfon Gryffydd <ArfonRG_at_DIEspammerSCUM.Texas.Net>
To: "Discussion re-collecting of classic computers" <classiccmp_at_u.washington.edu>
Subject: More thoughts on building a Z-80 (64bit!!!)
In-Reply-To: <19981022002017.2230.qmail_at_brouhaha.com>
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You guys are really raining on my parade....
I have looked at Z180's, Z380's and etc....   They are SLOW!!!!!!   The
only availabe packaging for the Z380 is un-useable to me as a hobbist
(without a lot of headache.)
I hate the way that Zilog has taken the nice and simple control bus scheme
of the Z-80 and really made it a pain-in-the-butt on the Z-380!.
<rest deleted>
Received on Thu Oct 22 1998 - 12:25:14 BST

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