===Video (graphics): modes, outputs===
Underlying the CPC's video output was the [[CRTC|Motorola 6845]] address generator. This chip was connected to a pixel generator that supported 4 bpp, 2 bpp and 1 bpp output (bits per pixel). The address generator was clocked at a constant rate so the 4 bpp display generated half as many pixels as the 2 bpp and a quarter as many as the 1 bpp.
The ROM featured three built-in display resolutions but many others could be achieved by reprogramming the 6845.