The 464+ and 6128+ are supplied with a system cartridge, which contains the operating system, Locomotive BASIC, AMSDOS and the free game "Burnin' Rubber".

The CPC464, 664 and 6128 had a 32K ROM on the PCB which contained the operating system and BASIC. The CPC6128 was also fitted with a 16K ROM which contained AMSDOS.

In the CPC+ these "roms" are contained in a single 128K ROM/EPROM inside the cartridge.

On the old CPC system, the operating system and BASIC were internal and always available, but this cartridge must be inserted if you want to use the operating system or BASIC.

What this also means, is that if you have a game cartridge inserted, there will not be any operating system or firmware and the game must provide it's own functions to access the hardware.

The 464+ and 6128+ are therefore useless without a cartridge.

If a cartridge is not inserted I see a coloured screen and nothing happens.

When the Plus is switched on with the system cartridge plugged-in, a menu is displayed, and you can select to enter Basic (by pressing f1) or play the free game "Burnin' Rubber" (by pressing f2).

The cartridge for the 464+ is identical to the cartridge for the 6128+ and also contains AMSDOS.

When the 464+ is initialised it starts up in cassette mode. Typing:


will return the message

Press PLAY then any key:

The AMSDOS disc commands are available, and, if you type:


then the message:

Drive A: user 0

will be displayed and the computer will lock up. Pressing SHIFT+CTRL+ESC will reset it.

If a user wishes to use a DDI-1 disc drive controller with the 464+ it must be modified do prevent the AMSDOS rom inside the interface from being activated.

Cartridge - Operating System

Cartridge - BASIC

The version of BASIC supplied with the CPC+ is Locomotive BASIC v1.1 and is the same as the CPC6128, except byte 3 of the rom data, the "ROM Version Number", has changed from 2 to 4. This is minor and programs written for the BASIC that comes with the CPC6128 will run on the CPC+ computers without change.

Cartridge - AMSDOS

The AMSDOS rom data has been modified.

As a result, any programs which use the removed commands, or access functions directly in the disc ROM will not work.

Hardware Differences

Internal differences

The CPC+ has a ASIC which comprises:

The functionality of the 8255, Gate-Array and 6845 is not identical to the CPC. As a result programs written which rely on special features of these chips may not work correct.

There are a number of titles which do not work. A common problem results in the keyboard or joysticks being unresponsive. These programs must be patched to allow them to work with the CPC+.

The details of the enhanced features can be found in the official datasheet.

Extra details, found from testing and experiments can be found in the unofficial datasheet.

On the CPC it was possible to hear cassette sounds (the sound from the cassette when a program is loaded or saved) through the speaker if the volume was high. However, the CPC464+ and CPC6128+ are silent.

External differences