Changes
CRTC
,/* HSYNC and VSYNC */
== HSYNC and VSYNC ==
On CPC, HSYNC and VSYNC from the CRTC are passed into the Gate-Array. The Gate-Array modifies the signals and then mixes these to form the Composite-Sync which is output to the display
On Plus, the ASIC handles both the ASIC and the Gate-Array but conceptually the CRTC within the ASIC is passed to the Gate-Array within the ASIC.
When HSYNC is active Gate-Array and ASIC output the palette colour black. If the HSYNC is set to 14 characters then black will be output for 14us.
The HSYNC is modified before being sent to the monitor. It happens 2us after the HSYNC from the CRTC and lasts 4us when HSYNC length is greater or equal to 6.
On a CPC monitor, the HSYNC is rendered in "absolute black". It is darker than the black output by the Gate-Array/ASIC. (The colours of the CPC are subject to black level, contrast and brightness, the SYNC black is not).
== The 6845 Registers ==
