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Skeleton+ not working..


George35

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I examined the Skeleton+ game code and I found a programming error, so Harmony is not the problem.

 

The game code produces an improper vertical sync signal, which is needed for a proper video display. This also explains why the sound works but you see no video.

 

If you want to play this game, I suggest using a different television, as yours seems to require a proper vertical sync signal while other televisions may not.

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Hi there,

 

I examined the Skeleton+ game code and I found a programming error, so Harmony is not the problem.

 

The game code produces an improper vertical sync signal, which is needed for a proper video display. This also explains why the sound works but you see no video.

 

If you want to play this game, I suggest using a different television, as yours seems to require a proper vertical sync signal while other televisions may not.

 

Where can I find the Skeleton+ source? Was it released publicly? I looked at the Skeleton code and the VSYNC routine looks to be fine. Did it change in Skeleton+?

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Hi there,

 

I examined the Skeleton+ game code and I found a programming error, so Harmony is not the problem.

 

The game code produces an improper vertical sync signal, which is needed for a proper video display. This also explains why the sound works but you see no video.

 

If you want to play this game, I suggest using a different television, as yours seems to require a proper vertical sync signal while other televisions may not.

 

Where can I find the Skeleton+ source? Was it released publicly? I looked at the Skeleton code and the VSYNC routine looks to be fine. Did it change in Skeleton+?

I did not find any source, I simply fired Skeleton+ up in Stella and found that the beginning VSYNC pulse occurred at cycle 20 in scanline 259 and the ending pulse occurred at cycle 9 of scanline 262. Ideally, the pulses should occur right after a WSYNC - i.e. cycle 3, but even though there seems to be a little leeway here, cycle 20 is way too late. Edited by batari
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Hi there,

 

I did not find any source, I simply fired Skeleton+ up in Stella and found that the beginning VSYNC pulse occurred at cycle 20 in scanline 259 and the ending pulse occurred at cycle 9 of scanline 262. Ideally, the pulses should occur right after a WSYNC - i.e. cycle 3, but even though there seems to be a little leeway here, cycle 20 is way too late.

Ahhh...I was just looking for the three scan lines. I totally missed the cycles when VSYNC is invoked.

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  • 3 weeks later...

Huh, this is the first time I've heard of this problem. (Or is it... hmm, vague memories of a complaint.) There was a bug in the original release of Skeleton+ (and maybe in the Activision compilation) where the YOU WIN screen would roll because I messed up the scanline counter. This was corrected in later carts.

 

I don't think the source for Skeleton+ was ever released. The source for Skeleton (possibly an early version) might be in the Stellalist archives.

 

However, I might be able to track down the source code and make a patch. I just happen to be transferring my backups to a new 2TB external drive.

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  • 5 months later...

 

However, I might be able to track down the source code and make a patch. I just happen to be transferring my backups to a new 2TB external drive.

 

Any word on the patch? I love the game, but it won't play on my HDTV through the Harmony cart, and I'm hesitant to purchase the cart of Skeleton+ itself if the error is causing havoc with my tv rather than the harmony...

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  • 6 months later...

I had this exact same problem when playing on my little brother's TV, which is very sensitive to scanline problems and screen rolls -- it was rolling on Gunfight, and maybe even one or two mainline commercial releases (can't remember which). We were using my Harmony cart and his Atari Jr.; I don't remember the make of the TV.

 

A fix would be great, especially if I eventually get him an AV-modded console so that he can enjoy the stereo effects (he's planning to get a Harmony cart).

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  • 1 year later...

Bumpity-bump!

 

I finally got my Harmony Cart set up last week and also noticed this problem with Skeleton+. The strange thing is... I own a Skeleton+ cartridge and it plays perfectly on my system and also using the Cuttle Cart. Why is there only a problem when playing it on the Harmony?

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  • 1 month later...
  • 2 weeks later...

Maybe this is the problem

START:
 SEI ;2
 CLD ;2
 LDA #$00 ;2
 LDX #$44 ;2
L1618:
 STA VSYNC,X ;4
 INX ;2
 BNE L1618 ;2

No idea why the first 44 bytes (TIA!) are not initialized.

 

Try the attached version. Maybe it helps. Not sure.

SkelPlus_Fix.zip

Edited by Thomas Jentzsch
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Interesting. Most of the TIA is initialized due to the mirror at $40-$6C so it's really just four registers causing all the trouble. I'm guessing something with VBLANK. I'm pretty sure that Harmony has VBLANK off when starting a game so Skeleton+ must not be turning it on (which is odd as all games should toggle VBLANK every frame.) Maybe this game does not use VBLANK at all? That would explain rolling issues others reported and indicates another possible bug in the game.

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Maybe this game does not use VBLANK at all?

After a brief test I think you are right. Most TVs can accept black instead of VBLANK, but some don't. Maybe depending on the brightness settings?

 

I had a similar problem in Splatform 2600, where TVs started to roll when the screen was flashing.

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