Could a Duo be modded so as to have more internal save capacity?

[Bardoly]

In any case, I think the question is settled. Yes, it -could- be done.

So..., who has the skill to do this, and is ready to give it a try?

[whisper2053]

$64k question right there.

*waiting with bated breath*

[spenoza]

Dude, eating bait is pretty gross. Perhaps you meant "bated breath".

[whisper2053]

Fair enough, I stand corrected! Also, I am just standing as well, but that is neither here nor there. Where is the electronics maestro who will bring us MAWR SAVE POWAH?

[bust3dstr8]

Nothing wrong with baited breath...calamari tastes gooood

[Bardoly]

In any case, I think the question is settled. Yes, it -could- be done.

So..., who has the skill to do this, and is ready to give it a try?

Anyone...?

[Marll]

This would be an interesting project to see tackled.

[Necromancer]

Steve is likely your best best for such a project.  Have you asked him about commissioning it as a project?

[TheClash603]

This sounds awesome.  Extra memory on a chip that didn't need to stay charged would be amazing.

Almost enough for me to consider letting my duo be used for the test...

[dshadoff]

As many other gamers have discovered, the save capacity of Duos is rather lacking, what with many of the later release RPGs saves taking up most (if not all) of the save capacity.

Is there any easy way that a Duo could be modified so as to increase the internal save capacity and allow more save games to be stored using the same internal memory manager?  If so, then I think that this would be a useful mod.

Well, without actually connecting up any hardware, the answer is at least "partially yes".

The internal save RAM is a capacitor-backed 2KB SRAM.

When David Michel first came out with MagicEngine, he "accidentally" allocated the savegame memory bank as 8KB, and realized that the CDROM memory manager was dealing with addresses beyond 2KB without any problems (or rather I should say, "without any fixed-size limitations").

So, one could expand the 2KB to 8KB.

However, I don't know if everything would treat the 8KB savegame naturally.
- Some games implement their own BRAM managers, so they migh not deal well with larger-than-2KB.
- Tennokoe banks would not deal with the size beyond 2KB well
- Not sure about the Memory Base 128/Save-kun unit either - or rather, I should say, not sure about the various MB-compatible games, and their associated BRAM managers.

Beyond that, one could take a larger-than-8KB (or larger-than-2KB) SRAM, and connect a certain number of the high-order address lines to a selector circuit, so you could "dial-in" a BRAM bank.  I've seen some PCB-mounted rotary switches which have 8 positions and BCD output, so one of those might work well.

For anything like SDCards or other flash memory, that's not really feasible, unless a related patch is made to the BRAM save functions inside of the CDROM card, if you use flash memory.  On the other hand, FRAM or MRAM may not have this constraint, and may actually be available in sizes relevant to this application.  Of course, you would almost certainly need some sort of 5V-to-3.3V (or lower) conversion circuitry.

[bishopcruz]

As many other gamers have discovered, the save capacity of Duos is rather lacking, what with many of the later release RPGs saves taking up most (if not all) of the save capacity.

Is there any easy way that a Duo could be modified so as to increase the internal save capacity and allow more save games to be stored using the same internal memory manager?  If so, then I think that this would be a useful mod.

Well, without actually connecting up any hardware, the answer is at least "partially yes".

The internal save RAM is a capacitor-backed 2KB SRAM.

When David Michel first came out with MagicEngine, he "accidentally" allocated the savegame memory bank as 8KB, and realized that the CDROM memory manager was dealing with addresses beyond 2KB without any problems (or rather I should say, "without any fixed-size limitations").

So, one could expand the 2KB to 8KB.

However, I don't know if everything would treat the 8KB savegame naturally.
- Some games implement their own BRAM managers, so they migh not deal well with larger-than-2KB.
- Tennokoe banks would not deal with the size beyond 2KB well
- Not sure about the Memory Base 128/Save-kun unit either - or rather, I should say, not sure about the various MB-compatible games, and their associated BRAM managers.

Beyond that, one could take a larger-than-8KB (or larger-than-2KB) SRAM, and connect a certain number of the high-order address lines to a selector circuit, so you could "dial-in" a BRAM bank.  I've seen some PCB-mounted rotary switches which have 8 positions and BCD output, so one of those might work well.

For anything like SDCards or other flash memory, that's not really feasible, unless a related patch is made to the BRAM save functions inside of the CDROM card, if you use flash memory.  On the other hand, FRAM or MRAM may not have this constraint, and may actually be available in sizes relevant to this application.  Of course, you would almost certainly need some sort of 5V-to-3.3V (or lower) conversion circuitry.

Cool info. Also, didn't the Duo-RX have 128k SRAM? I could have sworn I read that somewhere. If that's the case, how did the Tennokoe and MB work with that system? Of course I might be completely confused, but I could have sword I read the 128k thing somwhere.

[thesteve]

simple answer to the original question
the system could have additional bram added with a selector switch to chose 2K at a time
the dma controller does have more address lines then used in the ifu, as it addresses 2 ram banks in the duo which are managed by the sys card in the non integrated setups
however the system would only recognize the allocated 2K at any given time as its only identification is its address range as set in software

[megatron-uk]

Hopefully my everdrive-fat library will (at least partially) make the issue of save retention and storage space go away. Once I've finished it (read support is mostly done) I intend to create a bram tool that can save individual save records to SD card and load them back again.

[Duo_R]

Do you have a thread on this?

Hopefully my everdrive-fat library will (at least partially) make the issue of save retention and storage space go away. Once I've finished it (read support is mostly done) I intend to create a bram tool that can save individual save records to SD card and load them back again.

[Bernie]

Hopefully my everdrive-fat library will (at least partially) make the issue of save retention and storage space go away. Once I've finished it (read support is mostly done) I intend to create a bram tool that can save individual save records to SD card and load them back again.

Wait...this is a tool that is used through the Turbo EverDrive?  That would be sweet.  More info please.