Non volatil game boy saves (done on Pokemon Yellow, but problem on Pokemon Gold)

wadeVillines

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Alright, I'll try that! I just soldered it up without the pulldown and I get dark striped square sprites.
UPDATE: It works perfectly, however... My intention here is to still have a battery, for the clock, and when that runs out I can replace it without worrying about my save. With the 10K pulldown, and a standby output from the diodes of about 2.2v... That's drawing 220μA. Not a lot for a running console, but the battery I'm using (80mAh) will only last about two weeks. And that's before I even consider the F-RAM standby current. Looks like I'm better off getting one of those OR-gates after all :P
Lol, yeah I've got some great OR gates that draw about 4 micro amps and it works great. But hey, you can run the FM18W08 chip on system power (5v) instead of on battery. It doesn't need constant juice to work. If you're worried about your clock data, don't: the clock data is stored completely on MBC3, so this is the only chip that needs to be battery powered. For safety, you can use a 10K pullup resistor between #CE and VCC of your FRAM to make sure it only gets enabled when it's supposed to.

--------------------- MERGED ---------------------------

Very interested in a writeup/blog post with pictures!
It's on the way! I actually just bought a web domain to host it, and am typing up a bare-bones HTML site as we speak. I'll link you when it's ready to host.
EDIT:
The website is ready, but it is far from complete. You can find the gerber files for my board design, a parts list, as well as some other information related to the project.

Website is RetroReboot.net, it's about as simple as it gets, but I'm learning HTML as I go.
 
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Lol, yeah I've got some great OR gates that draw about 4 micro amps and it works great. But hey, you can run the FM18W08 chip on system power (5v) instead of on battery. It doesn't need constant juice to work. If you're worried about your clock data, don't: the clock data is stored completely on MBC3, so this is the only chip that needs to be battery powered. For safety, you can use a 10K pullup resistor between #CE and VCC of your FRAM to make sure it only gets enabled when it's supposed to.
I've ordered some OR gates and waiting for them to arrive. I'll just run the save chip and the OR gate both from system power. The gate should isolate the signals, so if the MBC is still holding one of those signals high, the FRAM won't be able to draw power through CE. I'm assuming none of the address lines are held high by the MBC without system activity?
The clock data thing is a bit obvious now I think about it. For some reason I had in my head that powering the save chip from battery had the secondary purpose of regularly updating the stored time or something, but I suppose that would drain the battery extremely fast!

Update: I've been waiting for those OR gates but apparently I never actually went to checkout...
Update2: They arrived and apparently the product image was wrong AND I misread the details so I ended up with microscopic chips I have no hope of soldering. Third time lucky?
 
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gonzaloj

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With mbc 5 i only have to replace And with mbc 3 i have to replace And OR ramcs And clk with output ce Signal.
But with mbc 1 And GBA? And What OR Gate i have to use?
 

gonzaloj

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With mbc 5 i only have to replace And with mbc 3 i have to replace And OR ramcs And clk with output ce Signal.
But with mbc 1 And GBA? And What OR Gate i have to use?
 

wolffangalchemist

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EDIT::gba::yay:
figured it out, wired it up, fired it up, and was very pleased.
i used aMB85R256 F-ram chip instead of a FM1808 either should work.
images for those who need would like to give it a go and showing it working.

M9rAnNB.jpg


gif video i uploaded of it working.
https://i.imgur.com/AgNWEL8.gifv

iaW8LgB.jpg


3lOMa69.jpg
AgNWEL8.mp4
 
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yafeee

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EDIT::gba::yay:
figured it out, wired it up, fired it up, and was very pleased.
i used aMB85R256 F-ram chip instead of a FM1808 either should work.
images for those who need would like to give it a go and showing it working.

M9rAnNB.jpg


gif video i uploaded of it working.
https://i.imgur.com/AgNWEL8.gifv

iaW8LgB.jpg


3lOMa69.jpg
AgNWEL8.mp4

Awesome !

Edit: tried this weekend with a FM18W08, it works perfectly :3

Thanks a lot for following up, I will add your fix to the first post !
 
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famiac

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PSA: If you replace your SRAM with FRAM (FM18W08) and use the OR gate method to provide the /CE signal, you may want to add a pull-down resistor to the CLK line.

This pull-down resistor guarantees compatibility with cartridge readers/writers like the BennVenn joey and sanni's cart reader if you're trying to back up or write new save data. These devices typically don't drive the CLK line when reading/writing SRAM data, which could prevent the FRAM chip from latching properly depending on how you generate the /CE signal.

I've tested this on six of my FRAM modded carts by shunting the CLK line to ground with a 10kOhm resistor and then reading/writing game save data with various devices. still need to test with my n64.
 
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MohammedQ8

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I wish I bought 5 of them for pokemon games. It plays and saves on Pokemon stadium 1.

Is it discontinued?
 

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famiac

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5 of what? my modded carts are just regular pokemon games.

I'm pretty sure the drag n derp carts are discontinued. But that's off topic. i would discuss flash cartridges in another thread.
 

MohammedQ8

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5 of what? my modded carts are just regular pokemon games.

I'm pretty sure the drag n derp carts are discontinued. But that's off topic. i would discuss flash cartridges in another thread.
I think I would buy gameboy Pokemon games with fram mods if they are stable and well built.

of drag and drop and modded Pokemon games with fram.
 

driverdis

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Bit of a bump here but has anyone run into the issue of Cypress’s FRAM FM18W08 SOP-28 being too small?

i ordered 10 of them and installed one today but it was a pain since I had to bridge the pad to the pin for every connection since the pads of the chip just touch the pads on the board on both sides.
 

wolffangalchemist

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I just saved a botched battery upgrade with this for a friend, was pretty grusome so figured i would post it, they got it off a guy who had no idea what they where doing , that poor pokemon silver pcb.... need to order a battery for rtc and possibly fix some traces but saving works again now.
20210921_004703.jpg

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20210921_004711.jpg
 
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