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snicklin

Cartridge RAM

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I ask a few questions on here related to cartridges, but only because I want to explore them more and more.

 

Are there any cartridges which have a number of their banks as RAM rather than ROM? It would be a great way to extend memory while still having an area with preprinted data.

 

I know you can write to Atarimax cartridges but it is not an obvious way of doing this.

 

Do any such cartridges exist?

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http://mega-hz.de/Angebote/THE!CART/THE!CART.htm

 

So in theory @tmp 's AVG Cart could provide the MEGAMAX 8 / 16K Mode where the bank switched cart area is writable too (if that is the correct model).

The issue with this is once you dirty the in-memory image then at what point can the cart save this back to storage?

 

 

With the UNO Cart, by extending the firmware, you can 'invent' your own cart models and exploit the RAM too.

So, for example, that was how I emulated the VRAM of a Gameboy by permitting writes to the cart window.

https://github.com/Wrathchild70/UnoCart/blob/firmware-split/source/STM32firmware/AtariCart/src/GameBoy.c

 

image.thumb.png.8663794e2e13233a0c2f69fa67ef9def.png

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SIDE3 has 2MB of user accessible SRAM without any modifications at all, and a DMA engine which can be used like a blitter of sorts. The SRAM is entirely utilised by the loader, but if you take care to clear the initialisation flag, you can use all the RAM for your own purposes without confusing the existing firmware.

 

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A 32K RAM cartridge was built and sold in Chile around 1990. It was like a pendrive, with its own driver, but without flash memory: it was standard RAM and it used a battery to keep the IC always powered.

 

You can read a description of it with photos in spanish in https://retrogames.cl/mcturbosoft.html.

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Q: A cart with RAM ? A: RAMcart.

Originally available in the 90s in Poland as 64k/128k Ramcarts, later also as 256k and 1MB Ramcarts and nowadays as 1MB, 2MB or 4MB Ramcarts:

 

Info at atarionline.pl (use e.g. google translate)

 

ebay: a) 1MB Ramcart

 

b) 2MB Ramcart

 

c) 4MB Ramcart

 

For the old Ramcarts (64k, 128k, maybe also 256k ) there were drivers available for DOS II+D and afair Bewe-DOS. For the new 1MB-4MB Ramcarts there is no software (or driver) available yet, as it seems...

 

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Thank you all for your input here. It is interesting to see that there are a few flavours of this.

 

Essentially I am interested in solutions that have ROM and RAM and that are currently well supported. As I am working on a game which will require lots of space but is also RAM hungry, the SIDE3 solutions sounds enticing. So much so I have just put an order in.

 

It is also interesting to see the RAM only solutions. I always thought that adding RAM only through hardware upgrades requiring soldering seemed a little bit over the top to me, but others may disagree as I guess you lose a cartridge port to some extent.

 

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On 10/2/2020 at 9:30 PM, flashjazzcat said:

SIDE3 has 2MB of user accessible SRAM without any modifications at all, and a DMA engine which can be used like a blitter of sorts. The SRAM is entirely utilised by the loader, but if you take care to clear the initialisation flag, you can use all the RAM for your own purposes without confusing the existing firmware.

 

I was wondering if you (or anyone else) has any docs on how use these features? I have taken a poke around the internet but did not find anything. You have some wonderful videos by the way.

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8 hours ago, snicklin said:

I was wondering if you (or anyone else) has any docs on how use these features?

I don't, but I will eventually provide some. The design was only completed a month ago and I still have to finish the user manual. :)

8 hours ago, snicklin said:

You have some wonderful videos by the way.

Many thanks!

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The!Cart is equipped with 128MB of flash and 512k of RAM.

 

In 8k mode ($A000-$BFFF) you can select the 8k bank and source (RAM/ROM) of that window (and ofc also disable the 8k to access the Atari RAM).

 

The!Cart also offers a "flexi mode" where you have separate bank, source and enable registers for $8000-$9FFF and $A000-$BFFF. This makes working with both RAM and ROM at the same time a lot easier as you can eg keep the A000 area at a single ROM bank while switching in various other RAM or ROM banks at $8000. Or have 2 different RAM banks mapped etc.

 

The predecessor to this flexi mode was the "8k-RAM" mode that I implemented on the TurboFreezer 2011. There you have 8k ROM (or RAM, if you want) mapped at $A000 and can optionally switch in RAM at $8000 (again via separate bank and enable registers).

 

I'm using this mode in the CartEmu menu of the Turbo Freezer to have a separate area to store presets. As the RAM on the Turbo Freezer 2011 has battery backup this is a really convenient way to have persistent storage (not limited by flash page size or having to fear wearing out the flash chip by excessive re-writes).

 

so long,

 

Hias

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On that note, I guess the Turbo Freezer 2011 could be considered an option as well. Although it's not a cart-port device per se; it is a cartridge that plugs into cart port + ECI on an XE system or PBI on an XL system; and does give you a pass through cart port on the connector for the XE's. It provides 512 KB of RAM (battery backed) for extended memory, 512 KB of RAM (battery backed) for cart emulation, and 1 MB of Flash for cart emulation (as shown in this thread: Turbo Freezer 2011 - Usage / Info). It also provides a lot of useful tools for development, including the ability to freeze program execution, a built-in debugger, DOS commands, and various ways to store frozen states of the machine.

 

Edited by MrFish
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16 hours ago, flashjazzcat said:

I don't, but I will eventually provide some. The design was only completed a month ago and I still have to finish the user manual. :)

Many thanks!

:) I don't think anyone will accuse you of being boneidle! Everyone knows that docs come last in any line of work!
 

I am just wetting myself at the thought of what I can do with all this space.

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3 hours ago, HiassofT said:

The!Cart also offers a "flexi mode" where you have separate bank, source and enable registers for $8000-$9FFF and $A000-$BFFF. This makes working with both RAM and ROM at the same time a lot easier as you can eg keep the A000 area at a single ROM bank while switching in various other RAM or ROM banks at $8000. Or have 2 different RAM banks mapped etc.

 

This flexibility sounds great for a programmer. It can get a bit fiddly swapping banks in and out all the time.

 

The thing that got me to put an order in for the Side3 was that it is currently available.

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On 10/5/2020 at 2:52 AM, snicklin said:

 

This flexibility sounds great for a programmer. It can get a bit fiddly swapping banks in and out all the time.

 

The thing that got me to put an order in for the Side3 was that it is currently available.

 

So is The!Cart, currently available at Abbuc shop for 75 Euro...

 

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On 10/2/2020 at 12:42 PM, MrFish said:

Supposedly MyIDE II has 512 KB of SRAM.

 

Yes, it does, but technically only 256K is directly available as 256K is reserved for MyIDE II stuff, if you boot up using the on-board MyBIOS and MyDOS, Atarimax Menu, etc.. But if you boot with an internal or other external OS and another DOS like SpartaDOS, then I think more than 256K is available, maybe even the full 512K. Otherwise the 256K that is not used by MyIDE II in sram is utilized by the FAT loader for rom images up to 256K (Commando, Mean 18 and others for example).

 

I was just starting to look into utilizing this MyIDE II sram memory with my SpartDOS X and Warp+/Qmeg 4 OS's because I only had 256K of internal ram, but then I got a Syscheck 2 for my XL with 512K sram and Incognito with 1MB for my 800 and no longer felt the need to look into it at this time.

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On 10/4/2020 at 5:42 PM, MrFish said:

On that note, I guess the Turbo Freezer 2011 could be considered an option as well. Although it's not a cart-port device per se; it is a cartridge that plugs into cart port + ECI on an XE system or PBI on an XL system; and does give you a pass through cart port on the connector for the XE's. It provides 512 KB of RAM (battery backed) for extended memory, 512 KB of RAM (battery backed) for cart emulation, and 1 MB of Flash for cart emulation (as shown in this thread: Turbo Freezer 2011 - Usage / Info). It also provides a lot of useful tools for development, including the ability to freeze program execution, a built-in debugger, DOS commands, and various ways to store frozen states of the machine.

 

I am waiting on Turbo Freezer to arrive in the mail right now. I haven't decided if I'll use it with my 1200XL with PBI or install it internally in my 800 with Incognito yet...I have also modified my 800 so I can use The!Cart and MyIDE II as well, with their sram, which I also already have both. So I can use them on either machine too, if the 576K or 1MB ram isn't enough on my two Atari's. I never thought I'd see the day when I have Atari's with so much memory and alternate memory options on hand!😀

Edited by Gunstar

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