SFCtoJAMMA - anyone familiar with this?

[Lemony Vengeance]

hey all,

I'm working on building out an SFCtoJAMMA adapter using MikeJMoffatt's code for a teensy++ 2.0. The info is located here:

GitHub - Mikejmoffitt/SFCToJamma: Decodes an SFC/SNES controller into simple inverted output

I've downloaded the INO, programmed the teensy, wired everything up per the pinout in the INO file, but when I test it with a JAMMA board (in this case, a CPS2) only two buttons work, Y (which registers as 2nd punch) and B (which activates the remaining buttons/directionals). When I don't have a controller plugged into it the buttons all press randomly and at the same time.

Is any one familiar with this? I'd ask mike himself, but he's a busy dude.

 

[dewmansnk]

Not very familiar with the project but that sounds like a pin floating or maybe not sharing the same ground.
1. The +5 and ground for the teensy I am assuming are coming from the Jamma edge?
2. Sanity check and get a DMM to continuity check the ground used on the teensy++ to the ground used for the buttons. If the buttons were wired to say JAMMA-(27,28,e,f) and the teensy++ to JAMMA-(1,2,a,b) you could potentially just not have a good common ground.

 

[Lemony Vengeance]

Not very familiar with the project but that sounds like a pin floating or maybe not sharing the same ground.
1. The +5 and ground for the teensy I am assuming are coming from the Jamma edge?
2. Sanity check and get a DMM to continuity check the ground used on the teensy++ to the ground used for the buttons. If the buttons were wired to say JAMMA-(27,28,e,f) and the teensy++ to JAMMA-(1,2,a,b) you could potentially just not have a good common ground.

1) Correct
2) the grounds are common in the adapter, and are going to the same pins on the edge. I wonder if voltage to the controlers is not common, however.