A later design is now available: SC725

This module houses a Z80 serial I/O (SIO/2) device (Z84C42xxPEG) and a Z80 counter/timer (CTC) device (Z84C30xxPEG), designed for use with the RCBus retro computers.

The Z80 SIO/2 provides two serial ports. Port A is fixed at 115200 baud when running the Z80 at 7.3728 MHz, while Port B's baud rate is software controllable.

The CTC provides four counter/timer channels. Channel 1 is used to control the baud rate of serial port B. Channel 2 provides a periodic timer tick. Channels 0 and 3 are available for connection to USER pins on the bus, allowing them to be used for general counting and timing, or to generate Z80 mode 2 interrupts for devices that can no do it themselves.

The module provides support for Z80 mode 2 interrupts, with the IEI and IEO signals available on a two pin header for linking with flying cables. These signals can also be optionally connected to the RCBus with jumpers.

Device addresses: SIO = 0x80 to 0x83, CTC = 0x88 to 0x8B.

Features

• Two serial ports
• Four counter/timer channels
• Tight address decoding
• Easy access to input and output signals on header pins or bus pins
• Interrupt daisy chain signals can be jumpered to bus or use flying leads

Documentation

Documentation can be found at www.scc.me.uk or by following the link below.

Compatibility

This module conforms to the RCBus specification v1.0 for RCBus-2014 enhanced 39-pin long modules.

The printed circuit board outline conforms to the RC2014 standard for full height modules.

The module is compatible with all RC2014 backplanes, all RCBus-2014 backplanes (RC2014 compatible including SC100 series) and all full RCBus 80-pin backplanes (including SC700 series). When used with 40-pin backplanes some of the features of this module are not available. The interrupt daisy chain can be implemented with Dupont cables if not supported by the backplane.

When used with a 40-pin backplane the pins in the second row are not connected. As a result the enhanced bus signals RX2 and TX2 are not available for the second serial port to connect to other modules.

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.

Printed Circuit Board

The printed circuit board is available on its own here.

Related items

• SC112 - Modular backplane
• Components, spares, and accessories

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.
• My products are made in accordance with the "designed for RC2014" labelling scheme.
• RC2014 is a trademark of RFC2795 Ltd.
• This product is designed for hobby use and is not suitable for industrial, commercial or safety-critical applications.