The serial port provides bidirectional asynchronous serial communications usually at 115200 baud, 8 data bits, 1 stop bit, no parity. RTS/CTS handshaking provides hardware flow control in both directions. The interface is at 5-volt (TTL) levels.

The main features of this design are:

• Classic 68B50 serial port
• Tight address decoding
• Address selection via jumpers
• Isolation of serial signals via jumpers
• LEDs to show transmit and receive activity
• Compatible with RC2014/RCBus
• Bi-directional hardware flow control
• Choice of three interrupt destinations
• Baud rate independent of processor clock speed

Documentation

The documentation can be found at www.smallcomputercentral.com

Compatibility

This module conforms fully to the RCBus specification v1.0 for 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 module, 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.

All of the integrated circuits supplied in this kit are brand new parts from major suppliers, such as Mouser, DigiKey, RS and Farnell, except for the 68B50 ACIA. The 68B50 has been out of production for some time and is not available from these major retailers. It therefore has to be sourced as old stock or as used components, but I do test them.

Printed Circuit Board

The printed circuit board is available on its own here.

Complete Systems

If you are looking for a complete system the following products might be appropriate.

• SC691 RCBus-40pin Z80 RomWBW SCM CP/M Computer
• SC114 RCBus-40pin Z80 SCM & BASIC Motherboard
• SC126 RCBus-80pin Z180 RomWBW CP/M Motherboard
• SC720 RCBus-80pin Z80 RomWBW CP/M Motherboard
• SC791 RCBus-80pin Z80 RomWBW CP/M Computer
• SC792 RCBus-80pin Z180 RomWBW CP/M Computer
• SC794 RCBus-80pin Z80 RomWBW SCM CP/M Computer
• SC131 Pocket-sized Z180 RomWBW CP/M computer

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.
• RC2014 is a trademark of RFC2795 Ltd.