The motherboard 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
• 512k byte Flash containing SCM
• Two asynchronous serial ports
• Two 5 volt SPI ports
• One 5 volt I2C bus master port
• Real-time clock
• Voltage supervisor
• Three expansion sockets

RomWBW is a 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.

The Small Computer Monitor (SCM) is my own classic machine code monitor. This is provided in the second Flash ROM. Both Flash ROMs can be installed at the same time, but only one can be selected at a time. Selection is with a jumper or external switch.

Expansion is available using the three 80-pin sockets. One is mounted horizontally to allow an extension backplane to be fitted, such as SC113.

Currently included with the kit is a micro SD card adapter to connect to one of the SPI ports. RomWBW supports SD cards for CP/M and Z-System file storage. This adapter is not a well behaved SPI device and prevents the use of the second SPI port.

The optional FTDI style serial adapter allows connection of one of the motherboard's serial ports to a computer running a terminal emulation program. A USB type A to mini-B cable is required between the serial adapter and the USB port of a computer. The motherboard has two serial ports which can be used at the same time, so you may want 2 serial adapters and USB cables.

Both the serial adapter and the micro SD card adapter can be connected directly to the motherboard or can be used remotely using the optional 6-way adapter cable.

The kit contains everything you need to build the motherboard, except a CR2032 battery, a micro SD card, solder, tools and cleaning materials.

Whilst the circuit board has a minimum of 2.54mm (0.1") component lead spacing, making soldering relatively easy, it is probably best not to think of this as a beginner's kit. It does, however, have a self-test diagnostic LED port, which can be very useful.

Documentation

The documentation can be found at www.scc.me.uk

Purchasing the PCB only

The bare PCB is available here on Tindie.

Dimensions

The assembled kit is approximately 10cm (4") x 17cm (7") x 6cm (2.5"). It is supplied in a box approximately 23cm (9") x 16cm (6.5") x 2.5cm (1") weighing about 300g (0.7lbs).

Notes

• This product is supplied as a kit of parts which 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.