Is anyone interested with the Z80?

The Z80 is still manufactured today and I was wondering whether there is any interest for a community or discussion group.

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Workshopshed over 9 years ago in reply to COMPACT +9

Here's some of the books I learnt about Z80 from, I donated them to the Cambridge computer history museum last year.
Former Member over 9 years ago +6

This is the circuit I made boards for sometime back to get people playing with them:
gdstew over 8 years ago in reply to COMPACT +6

I worked at Mostek maintaining the Fairchild Sentry testers used to test the Z80s when they first began to manufacturer them. The second computer I every built (parts, pcb, solder) was the SDB-80 which…

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DAB over 9 years ago

Hi Monte.

I used Z80's back in the 1980's and used to have a bunch of them around, but with all the other processors now available, they are not something I would try to use today. Too many support chips needed.

Given the Cypress PSOC, I would start there instead.

DAB
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COMPACT over 9 years ago in reply to DAB

HI DAB

As you know I've used both.
The issue with using modern parts is that one needs a PC and also allows one to gloss over the fundamentals with everything provided on a platter.

Building a Z80 system forces one to at least assemble some hardware, learn machine code if desired, have many more hazards to navigate and develop a full sense of what is going on.

Here's a comparison of the different levels of programming learned.

PSOC C
main() {
     unsigned char a=0;
     for(;;) {
          write_LED(a);
          a = ~a;
     }
}

Z80 ASSEMBLY
LED_PORT     EQU     %01

START:
     XOR A
$1:
     OUT     (LED_PORT), A
     CPL
     JR     $1

Z80 HEX
AF D3 01 2F 18 FB

Have a great day!
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DAB over 9 years ago in reply to COMPACT

Ah but have you looked at the ARM assembly language under the PSOC?

I suspect that it might be about as efficient as the Z80 code, but significantly faster.

DAB
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DAB over 9 years ago in reply to COMPACT

Ah but have you looked at the ARM assembly language under the PSOC?

I suspect that it might be about as efficient as the Z80 code, but significantly faster.

DAB
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COMPACT over 9 years ago in reply to DAB

Yes, but how do you program it into a PSOC without an accompanying computer?

I haven't looked at it in detail but;
A typical ARM and Z80 has its RAM access speed based upon the period of its CPU Clock speed.
At 8MHz it's 125ns for both devices (and 250ns for ROM on an ARM).

As for clock cycles required for each instruction, they require about the same give or take a bit.
Things get relatively more complex on an ARM because many of its instructions require 3 operands.
e.g.
ADC r1,r2,r3

Admittedly the Z80 has some limited 3 operand instructions with its index registers.
e.g.
LD A,(IX+d)

As for speed if we built a Z80 with SiGe transistors it'd operate at 210GHz at that speed it becomes difficult to interconnect it with other components.
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clem57 over 9 years ago in reply to COMPACT

As for speed if we built a Z80 with SiGe transistors it'd operate at 210GHz at that speed it becomes difficult to interconnect it with other components.
I kind of doubt that statement, sir. IBM claims SiGe speed records | EE Times back in 2004 claims a 60 GHz speed. But Z80 could operate faster if miniaturized to the degree the ARM is.
Clem
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COMPACT over 9 years ago in reply to clem57

Always good to be sceptical.

http://www.eetimes.com/document.asp?doc_id=1199863
https://www.researchgate.net/publication/3941932_013_mm_210_GHz_fT_SiGe_HBTs_-_expanding_the_horizons_of_SiGe_BiCMOS
https://books.google.com.au/books?id=sanRmmHKiMgC&printsec=frontcover&dq=isbn:1420066862&hl=en&sa=X&ved=0ahUKEwirgdiNga7…
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COMPACT over 7 years ago in reply to clem57

Milton Feng and Walid Hafez have an experimental BJT working at 605GHz. IBM and AMD claimed to have switching transistors as fast as 2.0-3.3TeraHertz.
At that speed I wonder how they'll dissipate the heat and everything would have to be soo close together to work.
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