the IDE/8255 Interface is a generic design of attaching an IDE compatible interface via the use of the 8255 PPI chip.
The IDE/8255 interface was developed along the information found on the internet to attach an IDE interface to a variety of 8 bit computers. To date all of the IDE interfaces that can be attached to the classic CPC appear to use a ribbon cable making it cumbersome to attach more devices.
The design of the interface also was an endeavor to resurrect my CPC as its internal disc drive died quite some time ago.
The interface uses ports &F8EF to &FBEF to control the 8255. The I/O lines used for the IDE/8255 interface are A10 and A4 (both low) to select the 8255, while A8 and A9 are used to select the 8255 Ports or Register. Version 1 of the interface does not have a through connector, but a future version will no doubt feature this so more devices can be attached.
The interface also includes a pin header for Compact Flash Card power. The power is attached to Pin 20 which is normally missing on the standard IDE interface specification. An adaptor card attached to the IDE cable would make it possible to use the CF cards (its a shame that the specification did not use the pin in this fashion a long time ago).
There are several pictures of the interface on the CPCWiki forum.