The Multiface 2 device (by Romantic Robot)

The Multiface 2 is a hardware device which plugs into the expansion port of the CPC and CPC+. It was designed and produced by Romantic Robot Ltd, London, UK.

Visually, the device is a small black rectangular box which has a through connector (to connect other expansion devices) and two push buttons. An earlier version has a toggle switch on the front.

Internally, the device has 8K of program ROM, 8K of RAM and some extra ICs.

When the device is connected:

The 8K RAM is used to store information about the state of the hardware when the stop button was pressed which includes CPU registers and hardware registers (CRTC, Gate Array etc), which are used to restart the program after the Multiface 2 releases control.

The RAM is also used by the built-in program to store it's working state, or to hold a user program.

There are other programs which use the Multiface 2 and an example of these are:

"The Insider" by Romantic Robot
A monitor program with a simple built-in assembler. This program is more powerful than the Multiface 2 standard monitor
"Soundhakker" by STS
A tool to to search for music data created with "Soundtrakker" music composer

When the computer is reset, the Multiface 2 will be "visible", this means it is possible to detect that it is connected and to use the functions to access it's 8K RAM. If it is "invisible" it can not be detected by programs. The stop and reset button will function regardless of whether it is "invisible" or "visible".

There have been different revisions of the Multiface design:

previous revision
This design has a physical toggle switch which is used to make the Multiface 2 "invisible" or "visible".
current and last revision
This design has a automatic switch which is used to make the Multiface 2 "invisible" or "visible".
Multiface 2 for CPC+
This has the same hardware design as the current revision for the CPC, but a different ROM. The Multiface 2 accessess functions direct in the disc ROM, and the location of some of these has changed in the CPC+ version of the disc rom.