Is it possible to use too few scanlines with bB?

[+Random Terrain]

I have been working on not going over 262 each frame and now I understand that using breakif { _scan>#262 } in the Stella debugger is even better than holding down Alt + f. Thanks to tips from this forum combined with simply rethinking things, the maze program I'm working on is not going over 262. But someone in another forum said something about using too few scanlines. Is that possible using batari Basic? If so, how do we make sure we're not using too few scanlines?

 

 

Thanks.

[SeaGtGruff]

I have been working on not going over 262 each frame and now I understand that using breakif { _scan>#262 } in the Stella debugger is even better than holding down Alt + f. Thanks to tips from this forum combined with simply rethinking things, the maze program I'm working on is not going over 262. But someone in another forum said something about using too few scanlines. Is that possible using batari Basic? If so, how do we make sure we're not using too few scanlines?

Not really-- at least, not if you're using the "canned" kernels and aren't messing with the timer.

 

As I recall, one or two of the earliest versions of bB were slightly off from 262 lines, but I don't remember if they were over or under.

 

If you write your own lernel, or if you modify the include files to change the timer settings in bB's canned kernels, or if you mess with the timer in your program, then you can definitely get fewer than 262 lines. Try this on for size:

 

   rem * Messin' with Sasquatch...I mean, the Timer
  COLUBK = $94
loop
  drawscreen
  TIM64T = 150
  goto loop

That should give you 246 lines. Hmm. To quote an old margarine commercial, "It's not nice to fool Mother Nature!" Or to put it as Popeye once said, "Leave well enough alone!" Don't go tinkering with the timer, and stick with the canned kernels, and you shouldn't have any problems with too few lines in bB.

 

Michael

[+Random Terrain]

Thanks. It's good to know that I normally don't have to worry about too few. I just need to make sure I'm not going over 262 and breakif { _scan>#262 } sure is a nice thing to know about.

[+Random Terrain]

In case anyone wants to know, I updated the Timing section again:

 

http://www.randomterrain.com/atari-2600-me...nds.html#timing