MiSTer FPGA Forum

Hi all,

My JAMMA cabinet has Btn 1,2,3 hooked up to the JAMMA connecter but a molex connector for the additional buttons. In the distant past I ran some individual wires from the molex connector directly to the terminals on the J-Pac and all was well. However, it seems that the Mistercade only has two options: Through the JAMMA or via CPS1-2 kick harness.

Or am I missing something?

After a fair amount of additional internet research, I've concluded that I should probably wire up btns 4, 5, 6 to the JAMMA connector and enable the CHAMMA switch on the MISTerCade, rather than introducing a CPS1/2 connector which I don't actually need for any boards.

This does hamper my ability to switch back and forth between the MISTerCade and the J-PAC which is a bummer, but I'll have to run some additional wires from the JAMMA to the J-PAC at a later date.

Has anyone solved this problem a different way?

Hi zorrobandito,

Did the CHAMMA switch allow you to use buttons 4/5/6 on the JAMMA connector? With wiring as follows: P1B4 -> pin 25, P1B5 -> pin 26, P1B6 -> pin 27, P2B4 -> pin c, P2B5 -> pin d, P2B6 -> pin e. I see in another post you ended up using the CPS1 kick harness but I was looking at using a 'J-PAC-C' version so that has buttons 4-6 on the JAMMA connector.

Thanks,
John

Here's how I solved it:

Problem: How to hook up the additional 3 buttons to the MISTerCade while preserving the pre-existing JAMMA harness and J-PAC + groovymame option?

What Would Capcom Do?
Capcom had an additional wiring harness for their 6 button games. CPS1 is the simplest.

Solution: Wire up a CPS1 connector.

Thanks to some helpful advice and parts from local electronics store, Jaycar, I've completed the surgery.

Parts:
60 Amp 12-way Screw Terminal Strip
10 Pin 0.1 Header with Crimp Pins - 2.54 pitch
wire - if possible, match the colours for the CPS1 connector (I couldn't but used consistent colours)

Method:
1. Check your wiring distance requirements with all components in their mounted positions. Measure two pieces. Strip the ends.
2. Wire the cabinet wires for buttons 4,5,6 - for both players - to the screw terminal strip
3. Wire both of the new wires into the same hole, matching the cabinet connections.
4. Wire the other ends to the 10 pin header. Be careful to check the positioning first. Pin 1 is marked on the MISTerCade board.
5. Wire the other set of ends to the relevant J-PAC screw connector - 1SW4, 1SW5, 1SW6 and 2SW4, 2SW5, 2SW6

Note: It seems the ground for the additional buttons is not required because it's already provided via the JAMMA edge connector.

I could have wired up the JAMMA connector as CHAMMA but I wasn't sure about the effect on the J-PAC and since it was working before...

Gaming nirvana - Achievement Unlocked

john-woods wrote: ↑Sat Aug 20, 2022 8:05 am Hi zorrobandito,

Did the CHAMMA switch allow you to use buttons 4/5/6 on the JAMMA connector? With wiring as follows: P1B4 -> pin 25, P1B5 -> pin 26, P1B6 -> pin 27, P2B4 -> pin c, P2B5 -> pin d, P2B6 -> pin e. I see in another post you ended up using the CPS1 kick harness but I was looking at using a 'J-PAC-C' version so that has buttons 4-6 on the JAMMA connector.

Thanks,
John

Perhaps I'm suffering from a long day but I don't understand your question. Buttons 4,5,6 were not wired to the JAMMA connector previously. They have been separate for as long as I can remember. Thus, I didn't need to mess about with the CHAMMA switches or format.

Sorry if I wasn't clear, but I think I figured it out.

I'm going a similar route to you (MiSTercade + J-PAC) but using a J-PAC-C version which has Player 1 buttons 4/5/6 on JAMMA pins 25/26/27 respectively and Player 2 buttons 4/5/6 on JAMMA pins c/d/e respectively. The MiSTercade would then have the CHAMMA switch in the 'right' position to allow it to also output buttons 4/5/6 for both players on the JAMMA connector. This needs all the relevant lines wired on the JAMMA harness to work as well obviously. I will switch between the two JAMMA inputs using a RiddledTV 2-way JAMMA switcher. It may be overkill but is an easy and flexible way to switch between the MiStercade and J-PAC-C JAMMA inputs.

That sounds like a much simpler problem than mine, though the CHAMMA aspect of the MISTerCade doesn't seem to be that well documented. I don't think you'll do any harm giving it a try.

Also, thanks for introducing me to the RiddledTV 2-way JAMMA switcher, I had no idea such a thing exists!

I also found that the MiSTercade is only well documented for the 'standard' features but requires a bit of digging and tinkering for any of the extra stuff. I suppose that's always the nature of such a product.

RiddledTV has lots of amazing products and great support, their stuff gets very positive feedback in many reviews too