Over the Labor Day weekend, I decided I wanted to convert some of my favorite NES games to the VS system. So like any other self-respecting nerd, I downloaded the Balloon Fight (USA) NES ROM, stripped the NES header off of it, split it into the PRG and CHR ROMs, burned them onto (3) 2764 chips, installed them in my red tent with a 2C03 PPU, and voila! I'm playing Balloon Fight. Players 1 and 2 are swapped, and I have to press 3P for Start, but I can play the 1P game as long as I want -- but if I play 2P Battle Mode, the ROM resets after one of the player dies (or at least I think that's the pattern).
So here is the burning question:
Or, if nobody knows the reason why it would happen, can anyone suggest a good investigative tactic to pinpoint the issue? I've considered bundling the ROMs up into a .ZIP and trying to debug the behavior with an emulator, but I'm not sure if the emulators out there would definitely reproduce the issue, so tips on doing that would be appreciated as well.
I'm not above modifying the ROM, if I can pinpoint with a debugger what code causes the issue.
The Why:
So Balloon Fight is a readily available game for the VS system, so why would I bother? Well, it's a 12-ROM game that requires using both sides of the red tent, with the only payoff being that each player can have their own screen. In my opinion, that's a serious design flaw and makes owning Balloon Fight on the red tent a tragedy, as it leaves the other side unavailable for something that 2 other people could be playing.
Pic of title screen
So here is the burning question:
Quote:
Does anyone know of a specific reason why the reset would happen during a 2-player game? I know the registers are swapped for player controls from the NES, but would this have anything to do with something I read elsewhere on this board about needing to read from $4017 (I think that was the location) at least once every second?
Or, if nobody knows the reason why it would happen, can anyone suggest a good investigative tactic to pinpoint the issue? I've considered bundling the ROMs up into a .ZIP and trying to debug the behavior with an emulator, but I'm not sure if the emulators out there would definitely reproduce the issue, so tips on doing that would be appreciated as well.
I'm not above modifying the ROM, if I can pinpoint with a debugger what code causes the issue.
The Why:
So Balloon Fight is a readily available game for the VS system, so why would I bother? Well, it's a 12-ROM game that requires using both sides of the red tent, with the only payoff being that each player can have their own screen. In my opinion, that's a serious design flaw and makes owning Balloon Fight on the red tent a tragedy, as it leaves the other side unavailable for something that 2 other people could be playing.
Pic of title screen