Non-volatile gameboy saves

[Snow_Cat]

Looks good. Did you leave the voltage supervisor in place?

[bassmasta]

Nah, I think the Xbox 360 has non-volatile memory for its clock.

No, it doesn't. Just unplug your 360, plug it back in, and turn it on without connecting it to Live. The clock resets.

[Haunted360]

Nah, I think the Xbox 360 has non-volatile memory for its clock.

No, it doesn't. Just unplug your 360, plug it back in, and turn it on without connecting it to Live. The clock resets.

You are absolutely right (I'll edit my post)

[Haunted360]

Huge bump

Remember this from the previous page?

I dunno :/
Just guessing. I have no idea about this stuff yet...

Now I do know


OK inside of your Gameboy Cartridge (Color), there is an IC on the bottom left, under the MBC5 IC.

This is volatile SRAM (http://doc.chipfind.ru/pdf/winbond/w24257.pdf" onclick="window.open(this.href);return false;), and it is linked to a DC inverter (this gives a steady 200 mAh to the SRAM no matter how powerful or weak the battery is, so it does not loose its memory) IC (http://www.ti.com/lit/ds/slvs141a/slvs141a.pdf" onclick="window.open(this.href);return false;) on the top left between the two.

If you de-solder this SRAM IC and replace the SRAM with any 256Kbit FRAM Memory IC with these matched specs, (http://ramtron.com/files/datasheets/FM28V020_ds.pdf" onclick="window.open(this.href);return false;) then it should work.

However, since there is no more power going through the DC inverter (no battery), some games MAY have different effects how they were programmed to store the data. As we know Pokemon Silver / Gold looses its clock / time in game, but the saves work.


I can make a tutorial and put it on my site, do more testing etc... but I need to order the FRAM IC first


Also, GameBoy Color games use CR2032 and GameBoy games use CR1616 if you need that information anyhow.


And these forums are awful! I keep having to press SHIFT + F5 to refresh my page as it keeps remembering the non-edited version. I lost my edited post, so I cam not re-typing it. Ah! It did it again!!

[jdmlight]

And these forums are awful! I keep having to press SHIFT + F5 to refresh my page as it keeps remembering the non-edited version. I lost my edited post, so I cam not re-typing it. Ah! It did it again!!

I thought it was just me! Happened only since I updated Firefox, and it happens on almost all of the forums I browse, so it's probably something goofy with the new version of Firefox.

[Haunted360]

And these forums are awful! I keep having to press SHIFT + F5 to refresh my page as it keeps remembering the non-edited version. I lost my edited post, so I cam not re-typing it. Ah! It did it again!!

I thought it was just me! Happened only since I updated Firefox, and it happens on almost all of the forums I browse, so it's probably something goofy with the new version of Firefox.

I use Chrome, and it still does it.

There is a setting in the Forum Admin Panel, to set the cache settings or something alone that line.
But Ben Heck himself can only fix this as we have figured out. So, it is not going to happen.

[bentendo64]

I am almost 100% certain that the clock is in the mbc chip, I beleive its mbc 3 in pokemon games? (besides Yellow, which is mbc 5).

And the GBC Pokemon games use cr2025, not cr2032, but the 2032 will fit.

[Haunted360]

I am almost 100% certain that the clock is in the mbc chip, I beleive its mbc 3 in pokemon games? (besides Yellow, which is mbc 5).

Ah, that would make sense.

Is there a block diagram of the MBC(3/5) somewhere?
If this is the case, the battery can be left in, but the SRAM can be changed to FRAM. A pin should also be lifted to stop the FRAM from getting any voltage on the SRAM V+ line.

[bentendo64]

Here is a pinout of MBC5:
http://devrs.com/gb/files/mbc5.gif" onclick="window.open(this.href);return false;

And this is supposed to be a discrete logic equivalent of the MBC1 chip:
http://devrs.com/gb/files/mbc1ro.gif" onclick="window.open(this.href);return false;

Correct me if I'm wrong, but aren't all of the MBC chips the same, but with a little variation with clocks and more memory that can be added?
Also, here's where I found those schematics
http://devrs.com/gb/hardware.php#hardgb" onclick="window.open(this.href);return false;

[Haunted360]

I dont think they would be exactly the same.

They would have a different data address or something to support higher megabits (ROM).

[qwertymodo]

Sorry to bump an old topic, but I thought I'd drop in and mention something. I see that the one issue (besides RTC) with this mod is that the FM28V020 chip is designed for 3.3V, but it's getting ~5.5v, so you have to lift the Vcc pin. Well, I happened across this document on RAMTRON's site http://www.ramtron.com/files/applicatio ... 28V020.pdf comparing the FM28V020 and the FM18L08, saying that they are mostly identical. This isn't very helpful until you notice that there is also a FM18W08, which is basically identical to the FM18L08 except a wider operating voltage range. So basically, the FM18W08 *should* be identical to the FM28V020 except with an operating voltage range of 2.7-5.5V. I haven't gotten a chance to try it, but if somebody else wants to give it a shot, I thought I'd drop that bit of info here.

tl;dr This chip: http://www.ramtron.com/products/nonvola ... spx?id=133 *should* be a complete, compatible, drop-in replacement for the Game Boy SRAM chip.

EDIT: Just tried it. It works. Get the FM18W08 instead of the FM28V020. It works 100%, without the need to lift Vcc, plus it's a little cheaper.