Re: [stella] Paddle demo

Subject: Re: [stella] Paddle demo
From: "Eckhard Stolberg" <Eckhard_Stolberg@xxxxxx>
Date: Sun, 24 Jun 2001 13:33:08 +0200
> My problem is this: if pot0 < $80, the program goes totally wacky.
> Can anyone help me figure out why the program crashes at $80 when it
> really be able to draw the sprite all the way to the bottom of the screen?
> Because of this, to get the program to start, the paddle needs to be
> counter-clockwise.

Line 71 should read "LDA #$82" instead of "LDA VB_DumpPots". VB_DumpPots
is defined as $80. If you leave out the #, you will read from address $80,
which is your vertical position counter. This causes your problem. Also
your code will turn off VBLANK during the entiry VSYNC and VBLANK part of
the frame, which is probably not a good idea. And finally you should stop
grounding the paddles after the three lines of VSYNC. That way the usable
part of the paddle will be about in the middle of the full possible turn.

Ciao, Eckhard Stolberg

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