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Ultimate Cart (SD multicart) - Technical thread


electrotrains

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Nope, there is nothing 100% compatible that Farnell stock. They suggest a couple of Xilinx contenders, but a brief look at their data sheet tells me they are not half as capable as this amazing little Alterra chip. One is even a BGA package, which is not something I want to encounter in a dark alley!!!

 

Hopefully however I have added another voice to the 'want' tray and when there is enough of us they will start stocking the thing locally. It really is a fascinating IC with an amazing amount of potential. Even to a complete novice in regards reprogrammable logic like myself it is clear using something similar could simplify many other mod devices currently available. Just the onboard flash is hugely useful all by itself.

Yes, you're probably not going to ever find an exact fit for an FPGA by a different manufacturer, that's typically not how that works.

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Hello to all. :)

A big thank you to electrotrains for the invention of this excellent device. :thumbsup:

 

For now I would like to add here a revised PCB design, based on his original schematics. The 47K pull up resistor across the pins of SD card, also included.

As I said this is based on the original schematics, so the same for the external dimension. That mean cause I can't provide it as is, in a Atari original enclosure.

If finally find the right mfg price here, and the members need something more than a neat PCB, then I must redesign it for the known Polish plastic enclosure as on my other cartridge constructions.

 

Lets see..

 

Eagle.rar

 

post-23371-0-83020100-1446759296_thumb.png

 

post-23371-0-52582200-1446759301_thumb.png

Edited by santosp
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Hello to all. :)

A big thank you to electrotrains for the invention of this excellent device. :thumbsup:

 

For now I would like to add here a revised PCB design, based on his original schematics. The 47K pull up resistor across the pins of SD card, also included.

As I said this is based on the original schematics, so the same for the external dimension. That mean cause I can't provide it as is, in a Atari original enclosure.

If finally find the right mfg price here, and the members need something more than a neat PCB, then I must redesign it for the known Polish plastic enclosure as on my other cartridge constructions.

 

Lets see..

 

attachicon.gifEagle.rar

 

attachicon.gifTop.png

 

attachicon.gifBottom.png

is that the cartridge case that doesn't fit in the 1200XL?

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Latest Eagle files with some more updates.

+3.3v traces upgraded to 12mil.

Altera logo added.

Frame and some graphical alterations added on schematic, for a better view.

All the vias above the edge connector, moved in a straight line.

 

 

attachicon.gifEagle.rar

Before I forget to mention it, I'd like to ask that you connect the SD card presence detect and write protect switch lines to some extra I/O pins on the FPGA. This cart has potential for use as a disk type device, and it'd be nice if the write protect worked in that case. Presence detect may also be useful of course.

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I like your idea Joey Z. :thumbsup: :)

I hope also electrotrains (the author) like this, and give me the exact pins which prefer on FPGA as to connect it.

I think the pins shouldn't matter all that much, as long as they're normal I/O pins. So probably whatever is free and convenient, as far as routing goes.

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Santosp,

 

While I'm sympathetic to Joey's request for the extra connections on the SD card, they aren't really necessary since there isn't yet any firmware that will actually use this extra information (though I hope this will change). Remember these changes to the PCB layout will carry a risk of it not working, unless thoroughly checked.

 

FPGAs can be picky about things like power and ground connections - the ground plane is now looking pretty fragmented and stiched together (compared to the original board).

 

However, I am a beginner at PCB design - this is the first "proper" board I've ever designed and tested, so I may be being too cautious!

Maybe someone with more experience can comment?

 

Robin

 

P.S. It's your board, but I'd prefer you lost the clipart train.

Edited by electrotrains
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Hi Robin.


Lets discuss first about the two extra connections on SD card. I connect each one from these with two I/O's of your FPGA.

Specific these two: I/O_118 and I/O_119

I follow your way as is with the tactile switch, and add two pull-up 10K resistors.


Frankly I see no reason to make guesses. All is clear on schematics also, and the only question to you the author is..

1. Could this work for you in a future firmware change?

2. And if yes, create problems as is now in good operation of FPGA?

I believe this is the most important point that should be clarified. ;)


As for the Ground plane, I believe that is far from enough. I have read cause the most frequent error who make many peoples about this ic, in to not connect (solder) the very important ground plane on bottom of the FPGA. This have as a result many anomalies in operation. :thumbsdown: :-o


But anyway. If you need more ground plane is very easy to add one more layer on TOP of PCB, as I make on my designs. Now I see cause this will override any need for grounding. Look on the pictures above, and lets keep this Eagle files as an alternative.


The logo is there only for fun, :-D and as you asked me on our p.m., I will remove it if I ever produce this PCB.

Although wrongly I had understand within our pm's, :? cause the problem was the old steam train logo.


Greetings Panos




post-23371-0-06327400-1446924708_thumb.png


post-23371-0-79981200-1446924711_thumb.png



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Panos,

 

If you've connected these SD card pins to IO pins on the FPGA, then there should be no problem and any future firmware would be able to use them.

It might be worth checking what pullups (if any) are required on these lines (if you haven't already done so).

 

As far as (2) goes - I was just making the point that by making changes to the board (rather than just doing a run of a known working board) there is a bit more risk to you than a straightforward reproduction. If you're comfortable with that, then fine. You've got a lot more experience of board production than I have!

 

The logo - I guess I just don't like someone else choosing a logo and placing it next to my name/signature (even for fun). The name by itself is fine.

 

Anyway, I'm looking forward to seeing the finished board, and if you have any spare PCBs when your run is complete, I'd like to have one!

 

Robin

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  • 3 weeks later...

One thing I would absolutely love to see is a feature Robin mentioned way back at the start, namely the ability of the 'UltimateCart' to be programmed to function as a 'SIDE2' - or other hard disk emulator - combined with stacked cartridge access. Presumably both the cartridge images and the physical storage space for the hard drive would exist on a single SDCard in a similar way to the 'SIDE2' and its "SIDELoader". That combination would I think be the ultimate IO device for the A8!

 

In fact, if I can betray a little blue-sky excitement here I've been doing some reading about this specific Alterra FPGA and I think it offers an absolutely huge amount of potential for future features and firmware. In practical Atari terms, I am not sure how much functionality you can add to the base system with a device that plugs in to the cartridge slot as opposed to the PBI. However the chip in itself is amazingly capable and I think you could pretty much run a whole emulated A8 as a hardware description on it alone in 'System On A Chip' fashion. Therefore I wonder if the versatility this gives to the 'UltimateCart' might not enable it to emulate a whole host of devices beyond the core multi-cart function?

 

It has prompted me to start the - very, very - long road of learning reprogrammable logic and virtual hardware description language. I come down to the ground with a bit of a bump when I look at that little task!!!

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  • 2 weeks later...

not sure this should be here as it's not really technical but how the heck are you guys fitting these into shells?

 

i bought an xe cart (barnyard blaster) as a donor, yesterday my friendly repairs expert came around (i don't get out and cant do anything like this myself) he opened the donor and after multiple attempts and dremmeling the shell to within an inch of it's life the cart simply doesnt fit, its too thick, the big black connector with the pins inside is simply deeper than the half of the shell it's suppose to fit in, the only way i can think of would be to cut right through the case and expose the connector to the outside.

 

any clues?

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Looking at my (small) collection of carts, the XE style/labelled ones seem to come in two varieties - there's either the ones that have identical shells to XL carts (with rough sides), or a different style with smooth sides, and a little "foot" on the underside of the cart near the top.

 

The PCB is designed to fit in the XL style ones - the other ones appear to be narrower, so maybe there is not enough space.

 

I guess you could make a hole for the programming header. At least it will be on the back/underside of the cart, so shouldn't look too unsightly.

 

Robin

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Looking at my (small) collection of carts, the XE style/labelled ones seem to come in two varieties - there's either the ones that have identical shells to XL carts (with rough sides), or a different style with smooth sides, and a little "foot" on the underside of the cart near the top.

 

The PCB is designed to fit in the XL style ones - the other ones appear to be narrower, so maybe there is not enough space.

 

I guess you could make a hole for the programming header. At least it will be on the back/underside of the cart, so shouldn't look too unsightly.

 

Robin

thanks, i'll take some photos of (whats left of) the inside of my shell later tonight, i cant do it at present as my kitchen looks like a bomb went off in a clothing factory as my career is doing the washing :) .

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If you've connected these SD card pins to IO pins on the FPGA, then there should be no problem and any future firmware would be able to use them.

It might be worth checking what pullups (if any) are required on these lines (if you haven't already done so).

In this case, since the two SD slot pins in question are switches connected to ground on one side, the internal FPGA pullups could be used without issue.

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Is it possible to put a version of SDX on to the cartridge? Obviously not a very important use, but interesting to experiment with.

 

Yes. The easiest ones to try are probably the atarimax 1mbit and 8bmit versions, and the SDX cartridge format is also directly supported in both the 64k and 128k varieties.

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Yes. The easiest ones to try are probably the atarimax 1mbit and 8bmit versions, and the SDX cartridge format is also directly supported in both the 64k and 128k varieties.

Ah! Many thanks Robin - I'll give that a try. Obviously this will mean selecting it from the cart menu. Is there any way to have an image file on the SD card to 'auto run' on start up?

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  • 5 weeks later...

Hi all,

 

Looks like someone else has successfully built themselves a cart...

(there's some rather nice pictures in his blog).

 

I ran it through google translate, since the original is in czech:

 

https://translate.google.co.uk/translate?hl=en&sl=cs&u=http://www.8bity.cz/2016/atari-ultimate-cart-sd-multicart/&prev=search

 

He seems to have had some problem programming the POF file from Quartus 15, and had to rebuild the whole project. If anybody else runs into similar issues, could they let me know, so I can figure out what might be wrong?

 

Robin

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