Changes

CRTC

274 bytes added, Wednesday at 09:32
/* Internal Counters */
No matter its type, the CRTC never buffers its counters.
The only value that is saved in a buffer in the CRTC is the video pointer MA because it is reloaded at each line start.  The exception is the CRTC 1 for which the MA is reloaded at each line start with R12/R13 instead of MA' as long as C4VCC=0. This is a major source of incompatibility if the programmer does not take care of this discrepancy. In demos and games, to make a display compatible with all CRTCs, program R12/R13 when VCC!=0. This will then take effect at the next frame start. <br>
<br>
5,617
edits