Z80 Explorer

Z80 Explorer

by ro on 22-12-2020, 15:22
Topic: Software
Tags: z80
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If you were exploring Z80 internals, emulation, or FPGA implementation over the recent years, you probably stumbled upon Goran Devic's blog call Baltazar Studios. He investigated and reverse engineered most of the z80 circuitry on a series of blog posts that are highly recommend. Recently he created a visual tool to explore the original Z80.

Goran's Baltazar Studios blog is a good resource on how the Zilog Z80 micro chip works. He shows you a Z80 built from the ground up; the heart, the soul, and the mind. It's all there. He also implemented the A-Z80 cpu for FPGAs which instead of targeting just the implementation of a software compatible Z80 core, actually did it closely following the design of the Z80. Very interesting because undocumented behavior does not have to be specifically coded and even potentially unknown behavior would still show up in his design.

This year, following some ideas and data from visual6502, he implemented a visual tool to explore the original Z80 design. You can visualize the individual nets and transistors and simulate the device while looking at is wave forms, exposing all Z80 internals in a visual/easy manner. A fantastic and invaluable tool for Z80 lovers!

relevant link: Baltazar Studios
relevant link: Z80 Explorer

originally submitted by Edevaldo
image by Hamlet

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Comments (5)

By MicroTech

Champion (385)

MicroTech's picture

22-12-2020, 20:14

Absolutely stunning!

By lintweaker

Champion (391)

lintweaker's picture

23-12-2020, 12:51

Brilliant stuff. I have an open tab in my browser to this for months now, so far never came around to give it a proper read it deserves.

By Whizzy

Master (205)

Whizzy's picture

23-12-2020, 15:09

Very impressive work, imagine doing this for a Ryzen processor...

By Juan Luis

Expert (121)

Juan Luis's picture

23-12-2020, 20:50

This waveform must be of a Z80 in a MSX because there is a wait state after each of instruction 1 clock cycle long. MSX could have been a little bit faster.

The wait state was introduced by ASCII corp. in order to use cheaper memories in MSX computers. This fact is commented in this web site, in wiki section but I don't remember the exact page.

By Edevaldo

Master (140)

Edevaldo's picture

05-01-2021, 01:07

Quote:

[Juan Luis:] This waveform must be of a Z80 in a MSX because there is a wait state after each of instruction 1 clock cycle long. MSX could have been a little bit faster.

It seems the author of Z80 explorer (Goran Devic) was more interested in the ZX Spectrum machines. His previous work was used for a FPGA recreation of a Spectrum. I do not know if the machine also has the the wait state during the M1 cycles, but I'm assuming it does.