This set of six printed circuit boards is designed to build a flexible Z80 system.

The system can be expanded to run CP/M and more.

Set of boards consisting of:

• SC102 – Z80 CTC module
• SC103 – Z80 PIO module
• SC104 – Z80 SIO/2 module
• SC108 – Z80 Processor module
• SC112 – 6-slot backplane with power input
• SC113 – 6-slot backplane extension

Once built this minimal system contains:

• Z80 processor
• 128k bytes RAM
• 32k bytes EPROM
• 7.3728 MHz clock
• Z80 SIO/2 dual port serial interface
• Z80 CTC 4 channel counter timer
• Z80 PIO parallel I/O interface
• Backplane with power input and 2 spare slots
• Backplane extension with 6 spare slots

Each board has a user guide which includes component sourcing and assembly details. These documents can be found on the documentation page of this site.

Communication to the outside world is achieved using the included serial board connected to a terminal or with an FTDI style serial adapter cable connected to a computer running a terminal emulation program.

This Z80 computer is designed to run the free Small Computer Monitor software version 1.0 configuration R3. Program a 32k byte EPROM (27C256) with this code and you have a capable machine code monitor, a BASIC interpreter and a CP/M loader.

To upgrade to a CP/M system, just add an RC2014 Compact Flash module and Compact Flash card containing CP/M.

You can purchase this set of printed circuit boards from Tindie.

Notes

• This product is designed for hobby use and is not suitable for industrial, commercial, or safety-critical applications.
• The product contains small parts and is not suitable for young children.
• RC2014 is a trademark of RFC2795 Ltd.
• RomWBW is copyright Wayne Warthen and has been provided free of charge with his permission.
• The Compact Flash interface circuit has been designed by Tadeusz Pycio and reproduced with his permission.

USA: not currently shipping due to new tariffs 24 July 2026