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View topic - Phantasy Star on Everdrive glitches?

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  • Joined: 22 Feb 2016
  • Posts: 27
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Post Posted: Thu Feb 18, 2021 2:54 pm
Someone recently made an open source adapter with 3d print files and a PCB design you can have made. It is literally just a pin to pin converter.

https://github.com/ms2gg/doc/wiki/Assembly-Instructions

That said, I've read some have had passive components. I recall reading about a resistor in certain models, and maybe another difference that makes "codemaster" games work on some but not others.

Edit: well naturally most of the info is already here, around the bottom on the pinouts page.

https://www.smspower.org/maxim/Documents/Pinouts

Although I'm still keeping an eye out for exact info on some of the other adapters
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  • Joined: 05 Sep 2013
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Post Posted: Fri Feb 19, 2021 11:09 am
Maxim wrote
They are all just physical adaptors. Some of the more exotic pins may not be the same on all.


So it puzzles me completely how can this affect the VDP timing.
It might be a power drain? If so, would replacing the (or have an additional) power source fix it?

In any case I would be really interested to find out exactly why it does work in some cases and it doesn't in others, that would help us into creating better hardware.
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  • Joined: 22 Feb 2016
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Post Posted: Fri Feb 19, 2021 1:29 pm
Well I finally bought a master gear adapter so I can use a real cartridge, although it seems like this is the most documented of adapters.

From pictures it looks like the nuby brand one has no screws. Can it be taken apart to investigate?

I did find the details about the resistor I mentioned earlier - sounds like a couple adapters have a pull up resistor built into them on the gg pin while the sega brands don't. From what I've read it makes the sega adapters not work with a majesco game gear. Sega consoles had it built in so their adapters didn't need it.

Maybe somehow there's a double pull up resistor is effecting the system in some way?

Edit: looked into it a little more, electrically and pinwise. Two resistors would reduce overall resistance. Looks like sega put a 4.7k resistor between 5v and the gg pin. I'd be curious if anyone with a multimeter and the nuby converter could check the resistance between 5v and the gg pins. Once we know that I can solder the same in parallel to my systems 4.7 resistor and see if it fixes things. For that matter I wonder if early everdrive gg units also had an extra/different resistor value here.
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