Enabling sixth button
By default the RGB-Pi JAMMA has pins 27 and e connected to ground to comply with the JAMMA standard, some machines have the ground of the buttons wired there.
However, the board has the ability to become a standard JAMMA+ with 6 buttons on the same JAMMA, as shown in the diagram.
┃P2 Button5 d┃26 Button5 P1┃ ┃GND/P2 Button6 e┃27 Button6 P1/GND┃ ┃GND f┃28 GND┃ ┗━━━━━━━━━━━━━━━━━┻━━━━━━━━━━━━━━━━━┛
To enable the sixth button in the jamma, we only have to section the two jumpers that we find on the board with the name of J1 and J2 until they have no continuity and we will map the controls in the operating system again.
If we want to reverse this change we should only solder a tin point between these two points.