Amstrad used CRTC (Cathodic Ray Tube Controller) from different manufacturers, which worked the same in the main, but do have many different characteristics. This is the reason why a demo designed for CRTC type 1, may not display correctly (or even at all), on a CRTC type 0 :
* CRTC 0 : chipset HD6845S,HD6845SP, UM6845
* CRTC 1 : chipset UM6845R,
* CRTC 2 : chipset MC6845,MC6845S, MC6845P* CRTC 3 : CPC+ Asic,ASIC AMS40489* CRTC 4 : ?CPC+ pre-ASIC AMS40226
The KC compact (KC mean KleinComputer = little computer) is a clone of the Amstrad CPC. It was made by VEB Mikroelectronik in East Germany (the old DDR) in 1989. It was made the year before the Berlin wall came down, and ceased production soon after. The KC compact is 95% compatible to the CPC. The functions of the Gate-Array are simulated by TTL-Logic and a Zilog Z8536 CIO. The ROMs are a patched English CPC6128 Operating system ROM (includes setup code for the Z8536) and a unpatched Locomotive BASIC v1.1 rom.