Save our High Scores - The Project |
Aug 15th 2001 LOTS !!!
So I actually finished the pages !! These hacks have been hanging around since the end of Feb. waiting to be documented, but I think they're worth the wait. Eventually... I'll update this page so it's not quite so sad looking.
Donkey Kong - Installation Details + Theory of operation & Source Code
Donkey Kong Junior. - Installation Details + Theory of operation & Source Code
Feb 12th 2001 PENGO
This is a patch I never quite got around to doing, but here are full details and pics of the upgrade. As the board uses standard 2k x 8 SRAM, it's pretty simple to replace with a non-volatile memory. Also as there's a lot of unused RAM in the game there's plenty of space for the saveing the high-score table.
The source code for the update is also available along with notes on the ROM patches made to support the additional code. Click here for the page Pengo High Score Save.
Feb 11th 2001 FROGGER updated !!
This is a reworking of the high-score hack I did for frogger a while back, it adds the ability to enter initials when you get a highscore and saves the high-score table to battery backed RAM, if it's present.
The initials input doesn't require the RAM to be added, the high-score table will just be reset when the machine is powered up.
Click for the "GC" Frogger High Score Save & Initials Enhancement .
June 1st '99 Q*Bert Battery
Replacement
Bah... made a error on the page ! The CORRECT part number for the RAM is DS1220 NOT DS1225
This is an upgrade I did AGES ago but never got around to documenting, as Q*Bert fans know the board contains a small battery to power the two RAMs which contain the high-score information. However, this battery is prone to leaking which can ruin part of the board. I decided to remove the battery and replace it with two battery backed RAMs that are extremely unlikely to leak and offer a life span of a minimum to 10 years. That'll keep your board & scores alive for a while.
Click for details Q*Bert Battery Replacement Page
May 29th '99 Dig Dug EAROM replacement
Wow !! I've not done anything about this for AGES.... So time for a quick update.
DIG DUG
By default Dig Dug will save high scores, however, to do this it used an EAROM, ( Electronically Alter Read Only Memory, I guess these were a pre-cursor to EEPROMs ??) anyway.. these parts required -29 volts to alter their contents and, worst of all, they're really hard to find these days. So a plan was formed to build a modern replacement, lacking datasheets and only having an overview of how thing worked and board schematics I started to build a prototype replacement.....Pics of the proto-board are here, it was pretty special...
Click for the pics Dig Dug EAROM replacement board.
Current status is that the board is being tested with some of the other Atari games which used the ER-2055 EAROM. Hopefully I've duplicated the ER-2055 'sufficiently' so it'll work as a straight drop in replacement as with Dig Dug.
The other BIG advantage of this board is that is DOES NOT need the -29v supply, it runs of a regular 5v single supply. This is great if you have a JAMMAtized dig dug boardset, it'll allow the scores to be saved !
More will follow SOON !!
Aug 17th Gaplus
ROMs and details now available, I've also added a save to Galaga 3 but I'm unsure as to exactly which RAM on the midway boardset is the one to replace with a battery backed SRAM. Hopefully I can get this figured out soon.
July 31st Mappy
The page & ROMs are now available.
Skykid update almost complete and I should have this up over the weekend, Gaplus has just been added to the list too !
So lookout for that hack soon (ish).
July 22nd Bombjack
I've just add the pages showing how to get Bombjack to save it's scores..
Please note: The battery backed Static RAM's used are DS1220 and M48Z02.
This whole thing started after a discussion, on rec.games.video.arcade.collecting and later with James Hagen, about the possibilities of making Galaga save the high scores after power off, if you've ever played for hours on a favorite game and achieved an all time personal best, then you'll understand how much of a loss it is to turn the machine off (like the first time I cracked half a million on Galaga).
So after disassembling the Galaga ROMs, and a few code hacks to the original game code, it was modified to not clear the high-score on power up, unless it was blank. The next stage was to ensure that the RAM used to store the score kept its contents even after power off, here low-power battery backed SRAM ( static RAM ) comes is VERY useful. However, Galaga uses 1k x 4 - 18pin RAMs and the smallest battery backed RAM is a 24pin 2k x 8, therefore a small adaptor board needed to be built which would then plug into the two RAM sockets on the Galaga video board.
Another possible technique was to source a couple of very low power 2114 compatible static RAMs, like the Harris 5114 - now these really are low power about 25uA @ 2v to retain their memory, you'd then need to add either a battery backed SRAM controller or build a small circuit to control the 'Chip Select' ( so that during power on/power off spurious writes to the RAM didn't corrupt it ). There'd also need to be a battery to supply back up power.
After some experimentation all-in-one SRAM approach was adopted as, overall, it's a much cleaner solution.
Once Galaga was patched this lead onto the next game, which for no better reason that James H. suggested it first, was Mr. Do, this proved to be much easier than Galaga, and only hardware modification was the addition of a socket for the RAM chip.
Now I'm on a roll an it's time to add 'save' to EVERYTHING... Well perhaps not everything but a 'few' favorites that could really do with it.
| Q*Bert - Battery replacement |
DigDug - EAROM replacement |
Gaplus - Program images and details of installation |
| Mr Do - Full details and modified program ROMs are available now. |
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| Mappy - Program images and details of installation |
BombJack - Program images and details of installation |
Galaga - Pictures of the plug in RAM board |
| Super Pac -Program images and details of installation |
Donkey Kong - Theory of operation, code updates and installation details |
Donkey Kong Jr. - Theory of operation, code updates and installation details |
Information, Pictures & Game Patches...
