22 Oct
1998
22 Oct
'98
12:04 a.m.
< I am trying to basically build a 64Bit Z-80
on a board. What I am
< looking for is: Anyone know of any chips that are EXTREMELY simple
< micro-controllers but, work at EXTREMELY high clock rates??? I wanna p
< a few on a board with some memory and made a 64-bit Z-80. I'd like th
< processor to operate at 300Mcyc (or faster) clock speeds so, I figure I
< need micro-controllers that operate at about 900 Mcyc to do the work.
Wait till April first for this.
<rotfl>
I don't think you were listening when we were
discussing propagation
delays. To deal with 300-900Mhz clock your talking 4-6layer etch and
some really fast logic. The .33nS memory will be tough to buy. Be
prepared to dump a few DecaKilobucks into the attempt after all you'll
need a really fast logic analyser and O'scope to see what you missed.
Gee Allison you are talking like an engeneer - destroying
a brilliant vision just by facts :)
If you want a 32 bit z80 get a z380, it runs native
z80 code, until you
switch modes then compatability works but it has a lot of gotchas.
Net thing, but just 18 and 20 MHz types availabe - running as
Z80 a 33 MHz Z180 might be faster (And never forget: you can't
use R any longer as random number generator :).
If your doing a z80 stretch, you better think about
how to access memory
or really alter the z80 fetch timing. Basic Z80 timing for say 20ns
memory would limit you to some 40-50Mhz... it would be a 5-10 MIPS machine
though. If you superpipline it and get it down to 1-2 clocks per cycle
you can double that.
THe Z180 is already down to 3 cycle/instruction, and the z380 is
down to 2 cycle/instr. But since the maximum clock rate of the
180 is more than 50% higher than the 280, it's the way to go.
In any case there is no way to logically stretch a
z80 without running the risk of making it software incompatable at some
point. I've seriously looked at it, still have the 2901s I was thinking
of using. I have z80/10mhz parts however and the 2901s would barely do
that.
And if you try, most 10 MHz can run at 12 to 14 MHz.
FYI: z80S180s can be had into the 30+ mhz range.
:) Jep and 1 Meg is still plenty of RAM when running CP/M
But after all where is the sense of having a Z80 as 64 Bit
processor ? It's a well usable 8/16 Bit processor. Even the
380 isnt realy an advantage - you just don't realy need this
32 Bit instructions. A set consecutive 16 Bit instructions
can do it in almost the same time. From my point of usage
a 16 Bit uP is anything you need - compact code, compact data
and greater over all performance.
Gruss
H.
--
Ich denke, also bin ich, also gut
HRK