Date   : Tue, 05 Dec 1995 10:28:34 GMT
From   : David Alan Gilbert <gilbertd@...>
Subject: Re: Screen timing/VSYNC interrupt/BeebDOS

James Fidell wrote:
 > 
 >     This is the vertical sync interrupt from the 6845.  CA1 is set up to
 >     interrupt ... as a vertical sync from the video circuitry is detected.

A good way to check this  out is to run Rocket Raid; if the ship
starts to disappear as you get to the top of the screen you've messed
up!

Dave

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