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

yafeee · Apr 14, 2013

Hi !

Recently I saw this post : http://forums.benheck.com/viewtopic.php?f=18&t=38664

To sum up, he replace the S-RAM chip of the original cartridge with a F-RAM chip (non volatil save). At the end a guy conclude that the FM18W08 chip is perfect to Pokemon Gold/Silver cartridge (he tried and it works).

I decided to apply this mod to my Pokemon Gold cartridge (I already lost my saves and replaced the battery 2/3 times). But a FM18W08 chip was not so easy to find, so I read some datasheets and found the FM1808 (old version of the FM18W08) as a solution. I ordered it from China, and tried to solder it on my Gold cartridge. Unfortunately, I didn't manage to have a working game (no save, and sprites in black and white). But I soldered the chip to my Yellow cartridge and it works.

Is it possible that I didn't solder the chip correctly on my Gold cartridge ? In fact, I had to insist, and solder/desolder to have a working Pokemon Yellow. If the chip is not adapted to Pokemon Gold/Silver, I will try to find a FM18W08, but I don't know where. I also have to buy a new Pokemon Gold, my cartridge is fucked up.

Edit: Thanks to Wolffangalchemist for giving us a working solution. Here is his solution for 2nd gen carts. Tested, it works great

wolffangalchemist said:
EDIT:
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.

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

GBA rocks · Apr 20, 2013

Cool project.

You may also be interested in the Drag'N'Derp card

http://derpcart.com/features.html

You would lose the Real Time Clock of the real Pokemon Gold cartridge though.

yafeee · Apr 26, 2013

This card seems interesting, but very expensive, and I want to mod the real cartridge.

I tried again on a new Pokemon Silver cartridge. As a result : the save dosen't work and I have graphic glitches (photos below). These are the same issues as my first attempt.

I really don't know why. I tried with and without alimentation on the F-RAM chip.

raulpica · Apr 26, 2013

Maybe the F-RAM chip is faulty? The soldering seems fine. Or maybe the "old" version has something that doesn't make it work with newer Pokémon games..

Anyway, sick project, I might do the same!

pyromaniac123 · Apr 26, 2013

How much does the FM18W08 cost? Cheapest I've found is $5.93 for 1.

yafeee · Apr 26, 2013

I tried with two different chip, on two different cartridge (Gold and Silver), and had the same issues. My Yellow moded cartridge is fully working, using one of the chip I used on Gold, so the chip is not faulty.

The original S-RAM chips are:

- lh52256cn-10ll on Blue, Red and Yellow

- bs62lv256sc-70 on Gold, Silver and Crystal

pyromaniac123 said:
How much does the FM18W08 cost? Cheapest I've found is $5.93 for 1.

Oh ! Where did you found FM18W08 ? Actually, I buy FM1808 chips from ebay at 9.6 USD.

pyromaniac123 · Apr 26, 2013

yafeee said:
I tried with two different chip, on two different cartridge (Gold and Silver), and had the same issues. My Yellow moded cartridge is fully working, using one of the chip I used on Gold, so the chip is not faulty.

The original S-RAM chips are:

- lh52256cn-10ll on Blue, Red and Yellow

- bs62lv256sc-70 on Gold, Silver and Crystal

Oh ! Where did you found FM18W08 ? Actually, I buy FM1808 chips from ebay at 9.6 USD.

http://www.aliexpress.com/item/FM18W08-FM18W08-SG-FM18W08-SGTR-RAMTRON-STOCK-IN-CHINA/667731292.html

If you are planning to do this to more than 1 cart.

http://www.aliexpress.com/item/FM18W08-SG-FM18W08-RAMTRON-SOP28-Free-shipping/751079156.html

More expensive but quicker than ordering 1 at a time.

yafeee · Apr 26, 2013

pyromaniac123 said:
http://www.aliexpress.com/item/FM18W08-FM18W08-SG-FM18W08-SGTR-RAMTRON-STOCK-IN-CHINA/667731292.html

If you are planning to do this to more than 1 cart.

http://www.aliexpress.com/item/FM18W08-SG-FM18W08-RAMTRON-SOP28-Free-shipping/751079156.html

More expensive but quicker than ordering 1 at a time.

Thank you ! I think I will buy the second one (5pieces). But before, I will try to understand why the FM18W08 should work instead of the FM1808.

Edit: I just bought 5 FM18W08 from Aliexpress, I'll post the results when I'll receive my order.

Rabby250 · Jun 9, 2013

Hello,

Sorry to bump this, but I had also run into exactly the same problem with FM18W08.

The detailed issues are:

After selecting "CONTINUE" from the menu after splash screen, the game will show that the save file you're going to load has "no player name (blank or null string), no badges and 0:00 play time". Pressing A afterwards will bring you to a blank screen where the game freezes (therefore the save file can never be loaded successfully). This is kinda strange, as in usual cases of corrupted saves the game will inform you when you select "CONTINUE", and force you back to the menu.
Almost all full-scale sprites (Trainers, Characters and Pokémons) and visual effects in battle (move appearances) will be displayed in black-and-white (not even gray-scale), but map sprites and palettes are normal. The main character sprite in the trainer info screen (where you check your badges) is the only known exception, which will be shown in color for unknown reasons.
The screen will show glitches during save overwrite confirmation dialog (the second yes/no option in a save), some other dialog (for example, when you're setting the day of week of your Pokéwatch) and between battle animations. In addition, the warning info - which should show up only if you are going to overwrite a previous save with a new game - will always show up, even when you are overwriting your current save.
The game will never ask you to reset your clock even if your battery was dead; instead, it automatically "sets" the time with a random (?) value dependent of the console you are using (for me, the time is always Thu. 10:15 for my GBA #1, Mon. 02:07 for my GBC, and Thu. 06:07 for my GBA #2 when testing with identical game cart and save file).

I believe this is not an issue related to the original SRAM, as the original SRAM on my testing cart (a Japanese Gold) was LH52256CN - the same one used in yafeee's RBY.
In fact, I've checked all my Gen I/II carts and found SRAM chips from 4 different manufacturers which share most of the specs, so the chip compatibility issues should be little to none.
(The only exception in all Gen I/II carts is Japanese Crystal, which uses 1Mbit SRAM. It's a pity that I couldn't find a matching FRAM to replace it.)

Guess we have to contact the guys who succeeded in the original thread to figure out what went wrong.

BTW yafeee, is the FRAM you're using a FM1808B? I'm considering one of those, but maybe I'll put it on hold if 1808B also fails. (Too bad I wasn't able to stop you from getting FM18W08.)

yafeee · Jun 21, 2013

Hi Rabby !

I sent a message to the author of the original thread (on mod retro forum, I don't find how to register on benheck), but he didn't respond for the moment. I will post his answer here if I'll receive a response from him.

About the FM1808B, I didn't use that one. I have 1808 only !

qwertymodo · Jan 3, 2014

I'm a member here as well, you could've PM'd me

It's hard to say what the issue is... first of all, buying IC's from AliExpress is hit-or-miss. Especially when they're offering them at 50-75% off wholesale prices. I'd start by ordering from one of their official distributors to ensure that the product is legit. Also, as has been stated here, they used several different SRAM IC's at various points in their production, and they are interchangeable, but different games did sometimes use larger capacity chips. The FM18W08 is 256Kbit, so if a game uses 1Mbit, you're out of luck, since I don't know of anybody that manufactures 5V F-RAM in 1Mbit capacities, and certainly not in a SO-28 package. Check to make sure that the game you're transplanting is 256Kbit. If it's 64Kbit instead, the FM16W08 should work. The only other issue I know of has to do with the way the chip enable signals differ between asynchronous SRAM and F-RAM. I know that for the games I've tested, the MBC pulses the /CE signal for every R/W cycle, but if it holds the /CE signal low for multiple consecutive R/W cycles, it won't work, because although SRAM allows that, F-RAM requires a falling edge for each cycle. If that's the case, then you'll have to cut a trace and add some glue logic. Sorry, I don't really have time to test it out myself, but I'm happy to answer any questions for anybody who wants to try it for themselves.

Edit: Didn't realize how old this thread was... sorry :/ Any way, if anybody who has tried this can tell me where the earliest point where you experience glitches on a brand new game is, I may be able to do some testing, but I need to know where the glitches occur or I'll just be poking around in the dark...

Rabby250 · Feb 27, 2014

Hello qwertymodo, thanks for the reply.

qwertymodo said:
first of all, buying IC's from AliExpress is hit-or-miss. Especially when they're offering them at 50-75% off wholesale prices. I'd start by ordering from one of their official distributors to ensure that the product is legit.

For my attempts, I purchased 5 FM18W08 directly from Mouser and fully reproduced yafeee's issue with them, so I think it could hardly be an FRAM-side issue.

qwertymodo said:
Also, as has been stated here, they used several different SRAM IC's at various points in their production, and they are interchangeable, but different games did sometimes use larger capacity chips. The FM18W08 is 256Kbit, so if a game uses 1Mbit, you're out of luck, since I don't know of anybody that manufactures 5V F-RAM in 1Mbit capacities, and certainly not in a SO-28 package. Check to make sure that the game you're transplanting is 256Kbit. If it's 64Kbit instead, the FM16W08 should work.

All Pokémon games except Japanese Crystal use 256Kb SRAMs, so the root cause wasn't related to this either.
(For 1Mb games, the most possible candidate I could find was Everspin's MRAM, although it only comes in 3.3V .)

qwertymodo said:
The only other issue I know of has to do with the way the chip enable signals differ between asynchronous SRAM and F-RAM. I know that for the games I've tested, the MBC pulses the /CE signal for every R/W cycle, but if it holds the /CE signal low for multiple consecutive R/W cycles, it won't work, because although SRAM allows that, F-RAM requires a falling edge for each cycle. If that's the case, then you'll have to cut a trace and add some glue logic. Sorry, I don't really have time to test it out myself, but I'm happy to answer any questions for anybody who wants to try it for themselves.

Is it possible that different MBC chips of the same kind (for example, different MBC3 chips) could generate different pulse patterns?
I'm asking this because in my current attempts so far, all Pokémon games with MBC3 will (and will only) run into this issue,
and the only success case was Pokémon Yellow, which uses MBC5.
However you did succeed on Pokémon Red (U) (should be an MBC3), which made me very confused.

And BTW, after getting frustrated, I tried a bizarre combo of Pokémon Gold ROM + MBC5-based main board,
and it actually worked - until I found out that you could never use Box 7 (or 8) in Bill's PC.

qwertymodo said:
Edit: Didn't realize how old this thread was... sorry :/ Any way, if anybody who has tried this can tell me where the earliest point where you experience glitches on a brand new game is, I may be able to do some testing, but I need to know where the glitches occur or I'll just be poking around in the dark...

You can reproduce this issue easily by following the steps below:
1. Find a Pokémon game with MBC3 and replace the RAM:

Yellow in Japanese region
Red/Blue in US region
Gold/Silver in any region
Crystal in any region except Japanese

2. Play the game until Professor Oak shows up for the first time;
you will know that you have ran into the issue if you see:

In RBY, nothing (the dialog was running, but no sprite)
In GSC, Oak's sprite in binary black and white (see yafeee's DSC01858.JPG)

3. Try to save once and restart to load your game:

In RBY, you can load your game (only the sprites are gone)
In GSC, you save will be corrupted

Thanks again for helping out!

qwertymodo · Mar 17, 2014

Thanks for the details, I'll look into it when I get a chance, but it's finals week right now, and I have a ton of projects on my plate. Also, I don't come around here very often, so chances are, I will forget about this thread. If you want, feel free to hit me up by emailing to my username at yahoo. That's kind of my junk email account, but I do still check it regularly. Like I said, I have a ton of projects, but I tend to gravitate towards the ones that generate the most interest, so if you start emailing me twice a week asking for updates I might actually get around to it

Also, I did mod a USA Red version, but I only played it through the title screen (it was a mod for a friend, and I only tested so far as to confirm the game booted, naively believing that it would work consistently after that...). To be honest, the only game I've played for any length of time with the mod is Zelda DX, which is also MBC5... so maybe MBC3 doesn't work, but it's weird because stuntpenguin claimed the FM28V020 worked fine, and it uses the same input latching

However, if I can test it out to confirm my suspicions, it may still be possible with the glue logic I posted above...

loco365 · Mar 17, 2014

I'm actually really curious as to whether this will work. I have a Japanese Crystal, however, the doofus that "repaired" it, shorted out the save chip, so it cannot save anymore. If I can replace the save chip with one of these, I'd gladly order one and replace it.

Dym · Jul 23, 2014

I have a few European Red, Yellow and Blue carts that are all MBC5, will the FM18W08 chip work with them? Thanks!

yafeee · Jul 23, 2014

Dym said:
I have a few European Red, Yellow and Blue carts that are all MBC5, will the FM18W08 chip work with them? Thanks!

Yes, it will work !

Notanyonewhocares · Jul 26, 2014

FM18W08 can be purchased here hurry: http://www.ebay.com/itm/FM18W08-SG-...511?pt=LH_DefaultDomain_0&hash=item4174da093f

qlb1234 · Jan 19, 2017

Sorry to bump an old thread.
To anyone who's still wondering whether there's a solution, the short answer is "probably yes".
TL;DR: You can probably replace the SRAM on a genuine Pokemon Gold cartridge with an FM28V020.

The main reason, as stated by qwertymodo at #11, and by BennVenn here, is that FM1808 (or other variants) doesn't support continuous read. Section "Pin Definitions" on Page 3 states that,

Chip Enable: The device is selected when CE is LOW. Asserting CE LOW causes the address to be latched internally. Address changes that occur after CE goes LOW will be ignored until the next falling edge occurs.

Loud and clear. This feature - multiple read operations in one cycle of /CE - is a feature of majority SRAM chips, e.g. W24257. Rabby250 at #12 listed some Pokemon games which won't work with FM1808:

Yellow in Japanese region
Red/Blue in US region
Gold/Silver in any region
Crystal in any region except Japanese

They're all newer Pokemon games (except that OP tried it on European version of Yellow, which was released in 2000, still works), as opposed to Pokemon Red & Green. So the wild guess "they continuous read RAM" may very likely hold true. But I can't imagine how this flaw introduces graphic glitches.

The new generation of Cypress FRAM, whose name starts with "FM2", is capable of doing this. In fact, they even support continuous write, which is amazing if you're making a homebrew flash cart.

The reason I kept using the word "probably", is that I have yet to try an FM28V020 on a Pokemon Gold cart. I bought a used one for this yesterday but it's still on the way. I managed to replace the SRAM on my EMS 64M cart with a FM28V100 and I didn't get the glitch OP has encountered. I will order some FM28V020 and update as soon as possible. And for people who can't wait, just go for it.

Update: Don't do it. It doesn't work.
I was experiencing graphic glitch after replacing the original RAM with FM28V020. After I saved the game, the save file doesn't persist through reboot.

Maybe we should wait for yet another generation of FRAM chip, the one which will be truly functional identical to static RAM.

Original components: http://i.imgur.com/WwXf6rk.jpg

Graphical glitch:
http://i.imgur.com/S5gGNuN.jpg
http://i.imgur.com/u8RfDKo.jpg

Saving:
http://i.imgur.com/tUrvvye.jpg

wolffangalchemist · Feb 20, 2017

I was getting this issue bad on my mod i just did tonight but figured it out, i connected pin 20 (CE) directly to the ramcs pin on mbc5, works for pokemon yellow with mb85r256s Fram chip i (pulled from a dead gba game.) someone might want try it with these.
http://reinerziegler.de/mbc5.gif

willis936 · Feb 21, 2017

Thanks for that post qlb. That explained a problem I ran into after dumping $30 on a flasher and $45 on a flashcart from tindie. Non volatile saving is a nice to have. Having things actually work is a must have.

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

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