(Yet another) Z80 CPU Tester

General info

This project allows you to test a Z80 CPU.

It tries

1. to identify the CPU technology (NMOS/CMOS),
2. to identify the CPU manufacturer,
3. to test whether the CPU is still functional,

and helps

4. to find out the max. supported clock rate.

The above results will help to identify fake CPUs.

It does not test

• Interrupts
• WAIT and HALT inputs signals
• M1 and RFSH output signals
• BUSRQ and BUSACK signals

The hardware has following features:

• 32kb EPROM (27C256), alternatively an EEPROM can be used (AT29C256)
• 32kb SRAM
• 2 output ports (1x unidirectional, 1x read-back) with 16 LEDs
• RESET and NMI button
• 16 MHz / 20 MHz switchable
• 1, 1/2, 1/4, 1/8, 1/16 multiplicator (1-16 MHz / 1.25-20 MHz)
• Connectors for measuring CPU power consumption
• USB powered
• THT for easy soldering

This project is based on an idea of

• https://oshwlab.com/vitalian1980/z80-tester (Hardware, Public Domain)

and additionally based on ideas of

• https://bitbucket.org/rudolff/z80-tester (Software, No license)
• https://github.com/djtersteegc/z80-cmos-nmos-tester (MIT license)
• https://github.com/skiselev/z80-tests (Software, GPL-3.0 license)
• https://github.com/EtchedPixels/FUZIX/blob/master/Applications/util/cpuinfo-z80.S (Software, GPL-2.0 license)
• https://groups.google.com/g/retro-comp/c/rhKeKpXmAXM (Software)
• https://www.malinov.com/sergeys-blog/z80-type-detection.html

and finally Frank Cringle's Z80 instruction set exerciser

• https://github.com/begoon/z80exer (Software, GPL-2.0 license)

[Please check the licence files in the relevant directories. When you are interested in a PCB, please contact me.]

Technologies

The project uses KiCAD and zmac.

Examples

Zilog Z84C0020PEC from a Chinese marketplace. It is a U880 (running with 10 MHz):

(picture shows Z80 CPU Tester Model 1)