Ultimate Cart (SD multicart) - Technical thread

[HiassofT]

I guess it could use some kind of virtual memory backed by the sd card. With an lru policy.

Coping with cache misses would be the tricky part. Reading a 512-bytes sector within guaranteed 500ns would require a _very_ fast SD card. I think we're not quite there yet

 

so long,

 

Hias

[foft]

Halt the cpu back(eg jmp back to where it was) and pray it's not time critical;). I guess most carts so large are multi carts anyway.

[electrotrains]

I chose 1MB of SRAM because there are so many 1meg AtariMax images about (including Space Harrier, which occupies a whole 1MB cartridge). I don't know of any single game that uses more than this.

 

All cartridges bigger than this are simply multicarts themselves, and there would not be much point making a 4meg Megacart image and sticking it on the Ultimate Cart. You might as well just use the original ROMs/XEXs, or make a small Megacart image with a single game. Otherwise you've just got 2 layers of menu to navigate through, plus waiting time as the cartridge copies a massive file from SD->SRAM, just so you can use a tiny bit of it...

[TheMontezuma]

Yes, you are right.

The only reason for me is to use existing game collections (if you only have a *.car file).

However if you have a Megacart Studio project file, you can extract the original ROMs, XEXs and ATRs or simply create several smaller images (like 512kB) with less content.

I consider to add generation of the Megacart 1MB images to the Megacart Studio to get "more" out of the Ultimate Cart (the same way as I did with 2MB for The!Cart).

[TheMontezuma]

I attached a new version (6.0) of the Megacart Studio:

 

MegacartStudio.zip

 

It can generate now *.car files with game collections for Megacart 1MB carts, which are supported by the Ultimate Cart.

 

Megacart Studio is a java tool (Windows/Linux/Mac) and it can be used to create game collections for Megacarts (like Atarimax Maxflash Studio for Atarimax carts).

 

And some example *.car images:

DemoCollections.zip

Edited March 6, 2016 by TheMontezuma

[santosp]

My latest try on this excellent cartridge, with a view to easier-better adaptation on the original striped grey Atari shell.

Between the pictures included also some with dimensions, in order to facilitate the possible maker.

 

Also on this latest redesigned pcb, some parts have changed as to make easiest the construction, and take up less space on pcb.

 

Greetings to all.

 

Eagle Files Final.rar

 

 

 

Edited April 3, 2016 by santosp

[morelenmir]

 

My latest try on this excellent cartridge, with a view to easier-better adaptation on the original striped grey Atari shell.

Between the pictures included also some with dimensions, in order to facilitate the possible maker.

 

Also on this latest redesigned pcb, some parts have changed as to make easiest the construction, and take up less space on pcb.

 

Greetings to all.

 

 

 

 

That looks like a really nice job santosp!!! I notice you are using the modified PCB layout though - so it does have the convenient hole in the middle for the case support to screw through. Not an option for the original design.

 

The discussion of the 1mB SRAM 'limitation' allows an interesting potential in terms of the open-source nature of the UltimateCart. Given we know exactly how the cart works, right down to the firmware would it not be possible to add a larger SRAM chip with similar electrical characteristics to the design? I guess that might introduce potential timing problems and the like though. It would be nice if you could simply remove the existing memory with hot air and then drop a larger replacement in place. I am sure it would not be that simple though!!!

[electrotrains]

Nice work! Did you manage to keep the same fpga pin allocations?

 

Robin

[+orpheuswaking]

 

My latest try on this excellent cartridge, with a view to easier-better adaptation on the original striped grey Atari shell.

Between the pictures included also some with dimensions, in order to facilitate the possible maker.

 

Also on this latest redesigned pcb, some parts have changed as to make easiest the construction, and take up less space on pcb.

 

Greetings to all.

 

 

 

 

Oh SO that's how you got yours cased

[santosp]

@morelenmir

 

The hole in the middle there, is for the existing plastic tab on the striped grey Atari shell. Not for some screw, like the other known Atari grey shell.

A 2 MB static ram ic could be possible, but first Robin must make the needed alterations on firmware. I don't know if he wish or have the time to doing something like this.

 

@electrotrains

 

Yes Robin exact the same pin as in your original one!

 

@orpheuswalking

 

He he yes!

But also yours could be possible according the pictures of Montezuma and others. I hope Montezuma find the time some moment to give the alterations and dimensions of his work on this shell public.

You know this last version may be more compatible with the grey shell, but need also some handicraft work to place it inside.

 

Thank you all for your kind words.

Edited March 14, 2016 by santosp

[electrotrains]

The discussion of the 1mB SRAM 'limitation' allows an interesting potential in terms of the open-source nature of the UltimateCart. Given we know exactly how the cart works, right down to the firmware would it not be possible to add a larger SRAM chip with similar electrical characteristics to the design? I guess that might introduce potential timing problems and the like though. It would be nice if you could simply remove the existing memory with hot air and then drop a larger replacement in place. I am sure it would not be that simple though!!!

 

You can purchase a e.g. 2MB SRAM for not that much more (a couple of pounds) than than the 1MB chip I used. It wouldn't be a drop in replacement, however, you'd need to route the extra address pin to a spare pin on the FPGA, then tweak the firmware in a couple of places. Not a big job.

 

EDIT - Santosp has reminded me that the 2MB version of the chip I am using is 3.3V supply only, rather than the 3.3-5V allowable supply for the current 1MB version. So you'd also need to power the larger SRAM with the 3.3V supply on the PCB, rather than the 5V as currently.

 

However, I just don't see the point, and the cart is already quite costly in parts cost. The SRAM isn't available to the Atari, it is simply used within the cartridge to emulate the whatever was selected from the SD card. And (megacart collections aside) there are no cartridges this big. A future firmware could make the SRAM available to the Atari through the CCTL window ($D5xx), but that would be a completely non-standard RAM expansion, so unlikely to gather much support.

Edited March 14, 2016 by electrotrains

[Marius]

2MB is pretty useless since the cart has to transfer all the data from the SD card to the SRAM. I wouldn't say it is slow, but it will take some time, which is not making the experience any nicer.

 

For the purpose for what this cart is created for 1MB is exactly the right amount of RAM.

[Mathy]

Hello guys

 

That big black 2x5 pin connector really does hurt the eyes.

 

Sincerely

 

Mathy

[santosp]

Unfortunately Mathy the programmer's for Altera haven't a option for a smaller connector.

I feel cause if someone goes out of his mind the upgrades, and use it for this supposedly built (for me just to play and relax), this connector isn't needed at all after the initial programming.

Now if in the future release a major upgrade like to read / write .atr files from / to SDcard, and the user really need this, then he can just place (without solder) and keep with its hand a simple 10 pin male connector as to program it.

 

This is my opinion on the subject upgrade connector.

Edited March 14, 2016 by santosp

[Kyle22]

Is it possible to support type 21 (800 right slot). It's addresses at $8000-9FFF. I want to try Monkey Wrench

[mulcmu]

I just finished building a prototype for an acrylic case. It is 7 layers of 3mm acrylic "glued" together. The front is fixed. The back is held in place with clips at the top and screws toward the bottom. It is a bit rough around the edges as everything was hand cut and filed. The logo was transferred to the acrylic with the cutting template but got a bit damaged during assembly. It is a few mm longer than a stock shell, thicker at the top.

 

The fit in an 800xl was a bit more snug than factory shells but not excessively tight. Seemed to be shifted a bit toward the front. I've got a few design changes to make. The back will need some more clearance for the pin headers to remain installed and I clipped off some of the SD card plastic that extended past the top of the PCB.

 

So far looks like a viable option for a DIY shell. Getting the parts laser cut and engraved should be comparable in price to a 3d printed shell. The laser cut acrylic build would still require some pretty tedious assembly. The internal layout could be changed to support other PCB designs as well for other projects.

 

 

 

 

[flashjazzcat]

Now that... That's going places. Nice.

[Glen's Retro Show]

Will this work in an atari 400 or 600xl.. Or an xegs?

[Kyle22]

Until we get a fix for Right cart (type 21), I appended Atari BASIC Rev. C to the end of Monkey Wrench II. It works as a 16K cart, but it only likes 400/800 OS. I haven't looked at the code yet, but it should be patchable for XL/XE OS. Does anyone know of a list of common illegal entry points, and their proper replacements?

 

Monkey BASIC II.zip

 

[FULS]

Until we get a fix for Right cart (type 21), I appended Atari BASIC Rev. C to the end of Monkey Wrench II. It works as a 16K cart, but it only likes 400/800 OS. I haven't looked at the code yet, but it should be patchable for XL/XE OS. Does anyone know of a list of common illegal entry points, and their proper replacements?

 

Monkey BASIC II.zip

 

 

This link might help. http://atariage.com/forums/topic/125889-monkey-wrench/page-2?do=findComment&comment=1650472

[Kyle22]

Thanks, very nice.

[ultrasteve]

I just finished building a prototype for an acrylic case. It is 7 layers of 3mm acrylic "glued" together. The front is fixed. The back is held in place with clips at the top and screws toward the bottom. It is a bit rough around the edges as everything was hand cut and filed. The logo was transferred to the acrylic with the cutting template but got a bit damaged during assembly. It is a few mm longer than a stock shell, thicker at the top.

 

The fit in an 800xl was a bit more snug than factory shells but not excessively tight. Seemed to be shifted a bit toward the front. I've got a few design changes to make. The back will need some more clearance for the pin headers to remain installed and I clipped off some of the SD card plastic that extended past the top of the PCB.

 

So far looks like a viable option for a DIY shell. Getting the parts laser cut and engraved should be comparable in price to a 3d printed shell. The laser cut acrylic build would still require some pretty tedious assembly. The internal layout could be changed to support other PCB designs as well for other projects.

 

front..jpg

 

back empty.jpg

 

font with pcb.jpg

 

installed.jpg

 

I would totally buy one of these! Very nice work.

[ultrasteve]

Would one of these be easy to mod for the Ultimate Cart?

 

[+orpheuswaking]

Would one of these be easy to mod for the Ultimate Cart?

 

 

It's the right cart shell for the boards made my the OP and Panos, Easy is debatable. I broke almost all of the clips and ended up having to hot glue the case back together. Also the header on the back is a PITA to cut a hole for.

 

Mine looks ok from the front though

[ultrasteve]

Cool, thanks - I have one so will butcher it when my cart from Panos arrives