I think the most likely cause is the wire length. When I was making my
"anygame cart", I found that I could not use a long ribbon cable, but did
not have a problem when I kept all the wiring(cart connector to all
circuitry) less than 6in. When I made my portable atari, I started with a
6 switch PCB, and used a ribbon cable to re-locate the cartridge
connector. This cable is 3 inches long. with no connectors between. My
portable has some problems with a few games, pitfall! being the most
likely to fail. I have seen similar problems using a "rom scanner".
For development, I would recommend just using a "simpler" game. If your
final product is enclosed in a cartridge, this shouldn't be a problem.
I did not spend the time to look at the signals on a scope to see was the
signal integrity is, but I'm sure that it is not good.
Mark
On Wed, 4 Dec 2002, Chris Larkin wrote:
> As the work on my flash cart continues on I'm still hitting some major bumps... During a routine test this morning, I programed the cart with Pitfall, and placed it in the VCS... when I fired it up.... nothing.... So I checked over everything, every little last detail, still nothing....
>
> So I manually manipulated the Address Lines and read the data out of the EEPROM with a multimeter on the cartridge connector pins, and it coinsided perfectly with the data in the ROM image... I even checked the FFD start address, and it is correct in the EEPROM...
>
> This was working fine before, and as usual now it is Caput... so I seek the help of you all... I removed everything from the breadboard except the EEPROM and the hex inverter... the only thing I think this can be is the length of wire coming from the PCB to the EEPROM, it's about 6 inches a wire... do and of you think this could be the problem???
>
> Or the EEPROM is corrupt some how, I cannot check all 4096 addresses by hand, so I checked about 35 different area's of the ROM, and they all came out correct.
>
> --Chris
>
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