looking for answers regarding n-card in mario 3

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infidelity
Posts: 490
Joined: Fri Mar 01, 2013 4:46 am

looking for answers regarding n-card in mario 3

Post by infidelity »

I apologize if this is the incorrect forum to ask this. Is there anyone here, that knows someone who knows the inner workings to Super Mario Bros. 3?

I ask because, I'm still in SRAM development for my nes all stars project. Smb1, and Smb2j .fds to .nes have working SRAM, and I'm currently working on smb2usa.

Awhile back, I created an SRAM feature for super Mario 3, but, it was a cheap way of doing it.

Anyway, in my old smb3 SRAM project, id backup the score, and when you return to the game, your previous score is restored. Now, if you have 80.000 or wayyy more than 80.000 times 3, and you defeat a stage, the n-card appears. But the issue I get, is once you won or lose that n-card, another will appear, and another after that.

I've looked online at Data Crystal, to check the RAM map, to see if there was some sort of register that limits the n-card appearance, but I couldn't find any. What I would like, is to know how to limit the n-card appearance when you restart your game with a vast high score. I'd like to know this before I begin working on the new SRAM for smb3.

I appreciate any info or contact info. Thanks everyone!

edit

found my answer, a very detailed document by southbird I believe. He didn't describe registers, but I he said within part of the reset vector, is a reset of the n-spade score. $7969 & $796A start with 1F,40. The reason for multiple N-cards, is because these 2 registers keep getting reset when you boot the rom up. So the sram work out there, including mine, probably is not restoring these registers. I increased my score manualy, coexisting with my n-card appearances, up to 3 times. Then, what I did, was I started a fresh game, altered my score to over 240,000,00 to inititate a 3rd n-card appearcance, BUT, at $7969 & $796A, I replaced it with 1F,40. Then what happened? I got 3 N-Cards in a row. So now I know what to do, for proper N-card sram usage.
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