[Coco] Q: CoCo2 border

Theodore Evans (Alex) alxevans at concentric.net
Sun Jan 11 15:36:02 EST 2004


On Jan 11, 2004, at 6:57 AM, jdaggett at gate.net wrote:

> Torsten
>
> Top border is 25 lines and bottom border is 26 lines. The right and
> left borders in pixel count are more dependant on the pixel clock
> frequency.

That just doesn't add up.  I frame of NTSC video has 525 lines 
consisting of two fields of 262.5 lines each.  CoCo video uses 192 
lines per field leaving a total of 70.5 lines unused.  It is possible 
that the CoCo colors only 51 of these lines, and in fact a certain 
number of these must be maintained as black in order to avoid extra 
lines being drawn during retrace, but they are still there.




More information about the Coco mailing list