I followed the instructions on this site and have added a pause switch to my SMS controller. Before I modded the console, I wanted to check that the controller worked correctly: however, after adding the switch, my Up direction doesn't work any more. Can someone recommend some troubleshooting steps so I can figure out what the problem is (and is there a way I can check that the switch is sending out the Up-Down signal without using a scope)? Thanks.
The pad is totally electronics free so just do continuity tests, the buttons connect pins to ground.
Thanks, that helped a lot. I found out that the switch was just stuck. I don't think I wired it correctly, though, because when I press it I don't get the Up and Down signals at the connector; I'm going to try reversing the diodes to see if I accidentally wired them backwards.
I know this it a bit OT but I thought since there's talk of controller pause it might be worth bringing up.
How complicated would it be to make a break out box so that one could use Mega Drive controllers and get the use out of the Start button?
I've often thought it'd be nice to just plug in a controller and have one button be 1, another be 2 and the third button to act as either 1 AND 2 or Up (for those annoying driving games). It would be cool to have the Start button work as expected. :)
In terms of a controller adaptor, it could be done in with a small microcontroller, as it has to poll the Mega Drive pad inputs and then emit the results as Master System controls. Maybe there is a problem if it needs more power than the control port can handle.
The harder part is the pause button, as it requires internal modifications to the system - but maybe you would just install the whole lot internally behind the existing controller ports. If you're doing that then why not swap the inputs for something better than a Mega Drive pad - maybe USB for current generation and PC controllers, or even go wireless. Or if you are a control pad purist, a Saturn 6-button pad, for example.
I am trying the pause button mod too but can't get it to work when I connect te controller's left and right connection to the switch with the 27KOhm resistors as mentioned in the tutorials. When I connect the controller's left and right to the switch directly (just wire, no resistors between the controller's connections and the Logic Gate) it works fine.
Does anybody know if having the resistors is necessary? Can I damage my console or games by not having them in?
Sorry for my ignorance, I'm fairly new at electronics and sega mods.
Thanks for your help!
I couldn't get it to work with the resistors, either. You can use bare wire, but you will need the 2 diodes if you have a SPST switch: otherwise, you're basically wiring UP and DOWN together, so that when you press UP on the Pad, it also generates DOWN (and vice versa).
You also need the diode to connect the IC chip (if you're using that option) to the NMI. Remember that the controller signals are active low, not active high (as is the NMI pin): for me, this meant biasing the diode the opposite of the way I was used to.
I did finally get it to work, although it was quite a slog. The instructions are correct (even the part about connecting to the VDP instead of the CPU: I thought that was an error, but it wouldn't work when I connected to the CPU).
