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I suspect this info is somewhere in the documentation on this site, but I struggled to find it.

The GG ASIC has these pins for these signals, and they all seem to come from the power board, with a few passive components in between.

I know it's used in part for the ASIC to detect battery voltage and adjust the battery LED as needed, but do these signals do anything else? I'm considering trying to put together my own power board for a consolized GG and just trying to research the details before hand.

Thanks!

I had to research this for when I designed my (to be released eventually) Li ion GG Power Board Pro. Theres a thread here somewhere about it.

Memory is a bit hazy but VREF is the voltage reference for the GG and is the most important. This is referenced for calculations and if the voltage is off here youll get really weird stuff (sound speeding up in games). Make sure you generate the exact (1.288v?) ref voltage from the power board to avoid this.

VRES IIRC goes to an internal opamp circuit for detecting battery voltage. I believe it has to be >6.5v or the system will not turn on. >8v to stop the power LED from blinking.

Anyway I might be able to look through my old docs later if ya need. What features are you trying to change / add for your project?

basically - my very modded game gear is having power issues. it has one of the common LCD upgrades, but also has GGTV with a genesis 2 plug, SMSFM module for FM sound, a PXLmod board for genesis controllers and start support, and one of those 3d glasses boards made up by segatom I think it was. I think I made a post here... somewhere...

All that stuff, plus running an everdrive, is just too much on the 5v line. It worked fine for a few months, but then started running into issues until the console has "warmed up" and caps get into spec (I assume).

I was thinking of a custom power board of some sort, since most all of it runs off 5v, but wanted to figure out the other signals before continuing.

After a few more months of thinking about it, and building a second game gear with a GGTV for a genesis 2 style plug, I plan to first try to see if the LCD upgrades can be easily modified for composite, so I can still have a genesis 2 plug. but without the added power draw of the full GGTV.

That's a lot of stuff crammed in there, no wonder you're having power issues :P it would be cool to see pictures of that, if you care to share. I'd specifically love to know how you got the FM mod going!

You may have seen my project called the GG Power Board Pro - it's a solution for this that gives you a lot more power for various upgrades. RetroSix / Handheld Legend also has a replacement power PCB (not as good, of course! ;) but yeah, I'm sure it's your 5V rail thats overloaded.

Note: GG Power Board Pro is being upgraded to the next version, and will be for sale towards the end of the year / early 2023 (hopefully, anyway).

Author	Message
asdfqwer426 Joined: 22 Feb 2016 Posts: 37	Help finding info on what VREF, VRES, and VONF do on a game gear? Posted: Tue Feb 01, 2022 6:07 pm
asdfqwer426 Joined: 22 Feb 2016 Posts: 37	I suspect this info is somewhere in the documentation on this site, but I struggled to find it. The GG ASIC has these pins for these signals, and they all seem to come from the power board, with a few passive components in between. I know it's used in part for the ASIC to detect battery voltage and adjust the battery LED as needed, but do these signals do anything else? I'm considering trying to put together my own power board for a consolized GG and just trying to research the details before hand. Thanks!

segasonicfan Joined: 05 Jan 2006 Posts: 374 Location: USA	Posted: Sun Mar 06, 2022 5:22 am
	I had to research this for when I designed my (to be released eventually) Li ion GG Power Board Pro. Theres a thread here somewhere about it. Memory is a bit hazy but VREF is the voltage reference for the GG and is the most important. This is referenced for calculations and if the voltage is off here youll get really weird stuff (sound speeding up in games). Make sure you generate the exact (1.288v?) ref voltage from the power board to avoid this. VRES IIRC goes to an internal opamp circuit for detecting battery voltage. I believe it has to be >6.5v or the system will not turn on. >8v to stop the power LED from blinking. Anyway I might be able to look through my old docs later if ya need. What features are you trying to change / add for your project?

asdfqwer426 Joined: 22 Feb 2016 Posts: 37	Posted: Thu Mar 31, 2022 12:23 am
asdfqwer426 Joined: 22 Feb 2016 Posts: 37	basically - my very modded game gear is having power issues. it has one of the common LCD upgrades, but also has GGTV with a genesis 2 plug, SMSFM module for FM sound, a PXLmod board for genesis controllers and start support, and one of those 3d glasses boards made up by segatom I think it was. I think I made a post here... somewhere... All that stuff, plus running an everdrive, is just too much on the 5v line. It worked fine for a few months, but then started running into issues until the console has "warmed up" and caps get into spec (I assume). I was thinking of a custom power board of some sort, since most all of it runs off 5v, but wanted to figure out the other signals before continuing. After a few more months of thinking about it, and building a second game gear with a GGTV for a genesis 2 style plug, I plan to first try to see if the LCD upgrades can be easily modified for composite, so I can still have a genesis 2 plug. but without the added power draw of the full GGTV.

segasonicfan Joined: 05 Jan 2006 Posts: 374 Location: USA	Posted: Thu Apr 07, 2022 1:59 am
	That's a lot of stuff crammed in there, no wonder you're having power issues :P it would be cool to see pictures of that, if you care to share. I'd specifically love to know how you got the FM mod going! You may have seen my project called the GG Power Board Pro - it's a solution for this that gives you a lot more power for various upgrades. RetroSix / Handheld Legend also has a replacement power PCB (not as good, of course! ;) but yeah, I'm sure it's your 5V rail thats overloaded. Note: GG Power Board Pro is being upgraded to the next version, and will be for sale towards the end of the year / early 2023 (hopefully, anyway).

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