With the recent free release of the universe bios 4.0 with the PICKnMIX I finally decided to purchase a 161 in 1 Neo Geo multi cart. PICKnMIX is a great feature, but I have discovered an issue with it that needed a fix. (This is not actually an issue with PICKnMIX it'self, but rather an incompatibility with certain setups. Razoola did a great job with the Universe Bios 4.0)
PICKnMIX must be enabled by holding the start button during the splash screen every time the Neo Geo is powered on. The problem I've found is that when using my Neo Geo on my New Net City with @invzims Jammafier it takes too long for the JVS I/O to initialize and I can't press the start button before the splash screen is already past. My solution, as with most things, was to write up a small program on a microcontroller to hold the start button for a couple of seconds at bootup then release it indefinitely. You can manually turn it on or off as needed using a switch.
This could also be helpful for people who are just lazy and don't want to bother with holding start every time they power on their Neo Geo (I can't say I wouldn't be one of those people too).
Here's the prototype.
As you can see I'm tapping into the pullup resistor arrays for the button inputs to access the start button, GND, and VCC. I have a NEO-MVH MV1A and I've designed a little PCB that will fit right over the pins of the resistor array for a more elegant solution.
It's specifically set up for the MV1A because that's the only Neo Geo PCB that I have access to, however if someone could check the pinouts of the resistor arrays of other Neo Geo motherboard types I might also be able to accommodate those. I just need to know where P1 Start, VCC and GND pins are on those other motherboard revisions and I can see if the design will fit.
PICKnMIX must be enabled by holding the start button during the splash screen every time the Neo Geo is powered on. The problem I've found is that when using my Neo Geo on my New Net City with @invzims Jammafier it takes too long for the JVS I/O to initialize and I can't press the start button before the splash screen is already past. My solution, as with most things, was to write up a small program on a microcontroller to hold the start button for a couple of seconds at bootup then release it indefinitely. You can manually turn it on or off as needed using a switch.
This could also be helpful for people who are just lazy and don't want to bother with holding start every time they power on their Neo Geo (I can't say I wouldn't be one of those people too).
Here's the prototype.
As you can see I'm tapping into the pullup resistor arrays for the button inputs to access the start button, GND, and VCC. I have a NEO-MVH MV1A and I've designed a little PCB that will fit right over the pins of the resistor array for a more elegant solution.
It's specifically set up for the MV1A because that's the only Neo Geo PCB that I have access to, however if someone could check the pinouts of the resistor arrays of other Neo Geo motherboard types I might also be able to accommodate those. I just need to know where P1 Start, VCC and GND pins are on those other motherboard revisions and I can see if the design will fit.
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