RE: [stella] Gravity Ball v015 - Thanks!

Subject: RE: [stella] Gravity Ball v015 - Thanks!
From: "Dennis Debro" <ddebro@xxxxxxxxxxxxx>
Date: Wed, 4 Jun 2003 06:30:10 -0400
Hi Rob,

I've got one more (sorry I didn't see this before). You're doing 30 scan
lines for overscan. Then before doing vertical sync you do one more
WSYNC. This gives you 263 scan lines. This is okay as most TVs should
show this fine.

I'd suggest your vertical sync to be...

   LDX #44
   LDA #02
   STA WSYNC  ; sync with end of last line of overscan from previous
   STA VSYNC  ; Enable vsync (happens at the beginning of the scan line)
   LSR        ; a now 0 saves a byte too--right Thomas ;)
   STA WSYNC  ; vsync for 2 scanlines
   STA VSYNC  ; end VSYNC (happens at the beginning of the scan line)

Then in overscan, reduce the scan line loop to 29.

Having VSYNC happen at the beginning of the scan line will guarantee
that even the sensitive 2600 (mainly jr's) will play the game fine. I
think Eric Ball did some research on this a while back. It's just one of
those "safe" things to do :)

I'm using X to set the timer so you're not dependent on the vertical
blank time to stop VSYNC. This will make things a little more flexible
if you start experimenting with VBLANK time.

Archives (includes files) at
Unsub & more at

Current Thread