The aim of this design is to provide a low-cost CP/M system. It uses the Z180 CPU for good performance and RomWBW firmware for robust implementation of CP/M with support for a wide range of hardware.

As a single board computer, it is able to run a wide range of CP/M software without any expansion cards fitted.

If you are looking for something a little simpler, you might like to consider SC114. For something a little more advanced, SC126 might be worth a look.

The kit comprises parts to build a Single Board Computer with these main features:

• Z180 CPU running at 18.432 MHz
• 512k byte RAM
• 512k byte Flash containing RomWBW
• Two asynchronous serial ports
• SPI port primarily for SD card
• Voltage supervisor
• Two RC2014 bus compatible expansion sockets

Optional items:

• Micro SD card adapter
• Serial adapter to USB
• USB cable, A to mini-B, 18"/500mm long
• Adapter cable, 6-way, 8"/200mm (requires header pins to be fitted to PCB)

RomWBW is a robust ROM-based operating system for retro computers. It includes CP/M 2.2 and Z-System and supports a wide range of hardware, including SD cards and Compact Flash cards for storage. RomWBW has been provided free of charge by its author Wayne Warthen. Thank you, Wayne, for providing this and all the support.

Expansion is available using the two 40-pin RC2014 bus sockets. One is mounted horizontally to allow an extension backplane to be fitted, such as SC141 and SC710.

Ordering

The full kit plus optional accessories (printed circuit board, component set, cables and adapters) contains everything you need to build a complete working system, except a micro SD card, solder, tools, and cleaning materials.

The ROM supplied in the component set is programmed with RomWBW.

You will need a terminal or a computer running a terminal emulation program, such as Tera Term, to communicate with the motherboard.

Documentation

The documentation can be found at www.smallcomputercentral.com

Compatibility

This computer conforms to the RCBus specification v1.0 for RCBus-2014 40-pin systems.

The RCBus specification includes RCBus-2014 (both RC2014 standard 40-pin bus and RC2014 enhanced 60-pin bus) and also the full 80-pin RCBus. The 80-pin RCBus provides support for advanced Z80 features, such as the interrupt daisy-chain, as well as support for other processor families.

The kit

This kit includes all the components needed to make the computer, as shown in the first picture. Other modules and backplanes shown in the pictures are not included. You will require tools, solder, and cleaning materials to assemble this kit.

The Z180 CPU (Z8S180xx) is no longer in production and finding stock is becoming increasingly difficult. The CPU supplied in this kit is either the 20MHz or 33MHz version, and is either old or used stock. I test all of them before packing in kits. Some of the CPUs have superficial scratches. All other integrated circuits are brand new and from major retailers in the UK or USA.

The assembled kit is approximately 10cm (4") x 10cm (4") x 6cm (2.5"). It is typically supplied in a box approximately 12cm (5") x 16cm (6.5") x 2.5cm (1") weighing about 150g (0.35lbs).

Printed Circuit Board

The printed circuit board is available on its own here.

Notes

• This product is supplied as a kit of parts that require assembly.
• It is your responsibility to pay any import duty or taxes charged by your home country.
• This product is designed for hobby use and is not suitable for industrial, commercial or safety-critical applications.
• RomWBW has been provided free of charge by its author Wayne Warthen.

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