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In development - SD card based Multicart

multicart homebrew fpga

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#1 electrotrains OFFLINE  

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Posted Thu Jun 11, 2015 3:49 AM

Hi All,

 

I thought I'd post to announce my new hardware project - I'm building an SD-card based Multicart.

 

https://youtu.be/PjkCTXqirv8

 

Although its far from being finished, it already shows the available ROMs/CARs on the SD card on an Atari menu, and will then reboot to the selected cartridge. At the moment it only supports 8k ROMS and 8-mbit Atarimax ROMs, with bankswitching etc, but I plan to support all cartridge types soon.

 

Adding a new ROM is simply a case of copying a new file to the SD card - no more flashing ATRs etc.

 

Not sure if there's any other available hardware that currently does this? I don't have an SIDE or MyIDE.

 

The hardware is a Altera Max 10 eval board, with my 3.3v cartridge breakout board attaching it to the atari. There's an external 1 megabyte SRAM which cartridges are copied to. Initially the atari boots to a small 8k boot ROM which is stored in dual port memory on the FPGA. The FPGA is also running a soft-cpu to copy files from SD card to SRAM.

 

I'm planning to make a PCB for this next, with the aim of fitting inside a standard cartridge case. Never done an FPGA board before, so that may take me some time. The boot ROM is also far from finished - I'm having to learn 6502 from scratch.

 

There are some other possibilities for this too - the same cartridge could be re-programmed e.g. as an atari co-processor/accelerator board. I'm planning to leave a JTAG/USB Blaster header on the board to make this easy.

 

Robin

 

ultimate_cart_prototype.jpg

 

 



#2 jvas OFFLINE  

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Posted Thu Jun 11, 2015 5:09 AM

Really a great idea! You can count me on when the production begins.

#3 morelenmir OFFLINE  

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Posted Thu Jun 11, 2015 5:23 AM

This is something I am extremely interested in!!!  Perhaps to the extent of buying the separate parts and building it via breadboard!!!

 

Absolutely fantastic work!  An SD solution for this problem is exactly what we need.



#4 Hyperboy ONLINE  

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Posted Thu Jun 11, 2015 5:43 AM

Love it, Count me in!

#5 Joey Z OFFLINE  

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Posted Thu Jun 11, 2015 7:58 AM

Just the other day I was thinking we really need an SD based multicart for the 8 bit, and I was going to put it in my long list of things I should do, but if you end up producing something for a reasonable price, that works too.

 

I am a believer in open source hardware and software in a hobby like this. We can't have proprietary software and hardware, forcing people to constantly reinvent the wheel when something goes out of production. Will you be releasing schematics and source code by any chance?

 

EDIT: also, if you need any help on this, hardware or software, let me know. I'm a college student on summer break with plenty of time on my hands currently. I have pretty good experience with 6502 assembly and I am studying to be an electrical engineer. In addition to that, I have plenty of previous experience with designing hardware. You can PM me if you want to talk, or post here if you prefer that, it doesn't matter to me.


Edited by Joey Z, Thu Jun 11, 2015 8:01 AM.


#6 electrotrains OFFLINE  

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Posted Thu Jun 11, 2015 9:37 AM

Joey,

 

I'm planning for this to be completely open-source (once I've finished the design). Having said that, its going to be pretty difficult to build one yourself at home (very fine surface mount parts).

 

Thanks for the offer of help - will send you a PM.

 

I'm not sure about getting the finished board produced in any quantity - if there's demand for more than about 10 of them (which seems possible), I'm unlikely to want to produce them myself at home. I'm doing this for fun and learning, rather than profit.

 

Any ideas welcome,

Robin



#7 brenski OFFLINE  

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Posted Thu Jun 11, 2015 9:49 AM

canvas opinion on how many would be genuinely interested

open a "poll" in the thread

 

 

  • not interested
  • interested
  • would buy


#8 Joey Z OFFLINE  

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Posted Thu Jun 11, 2015 9:54 AM

Joey,

 

I'm planning for this to be completely open-source (once I've finished the design). Having said that, its going to be pretty difficult to build one yourself at home (very fine surface mount parts).

 

Thanks for the offer of help - will send you a PM.

 

I'm not sure about getting the finished board produced in any quantity - if there's demand for more than about 10 of them (which seems possible), I'm unlikely to want to produce them myself at home. I'm doing this for fun and learning, rather than profit.

 

Any ideas welcome,

Robin

Right, of course the reason I say it should be open source is not so much so people can produce them at home, but so that people can produce them more professionally, in a larger quantity. Then they can sell them individually to people. It's not too difficult to get some boards made, but professional board assembly is a bit more difficult. Depending on how many parts there are, it probably wouldn't be unreasonable to get a set of boards made and hand solder the components. I'd be willing to produce a run of them and solder them as time allows, if there were interest in them.

 

Another issue is cart shells, getting some manufactured again adds to difficulty, making your own is probably even more difficult. Being a cart that needs an SD slot, it'd be difficult to adapt anything.


Edited by Joey Z, Thu Jun 11, 2015 9:55 AM.


#9 djmat56 OFFLINE  

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Posted Thu Jun 11, 2015 9:55 AM

would deffo buy one. I have two multicarts currently but its a pain having to keep flashing via the Atari



#10 thegamezmaster OFFLINE  

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Posted Thu Jun 11, 2015 10:40 AM

As part of the minority, I would love to see a affordable priced cart like this. And I realize the maker deserves to be compensated for their work but some of us most high prized items are out of reach. Good luck with your work!

#11 adam242 ONLINE  

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Posted Thu Jun 11, 2015 11:02 AM

 

canvas opinion on how many would be genuinely interested

open a "poll" in the thread

 

 

  • not interested
  • interested
  • would buy

 

 

Would buy.



#12 playsoft OFFLINE  

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Posted Thu Jun 11, 2015 11:32 AM

Hi Robin,

 

I would buy (really I would like two if you ever did more than a small run). I use the Atarimax Ultimate SD cart on the 5200 console and being able to copy to the SD card and run without any flashing is so much quicker. It also makes a cart API available to the 6502, so for example I can load level data in from a separate file instead of having all the level data contained in the cart image itself - so that may be something to consider.

 

Paul



#13 electrotrains OFFLINE  

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Posted Thu Jun 11, 2015 11:50 AM

Paul,

 

I hadn't heard of the Atarimax Ultimate SD cart for the 5200. I've been to the Atarimax website a few times, but tend to blank out the non Atari 8-bit stuff.

I wonder why a version for the 400/800/XL/XE was never released? The 5200 looks like it was very similar hardware, so it shouldn't have been a big step.

 

Also - damn! I was going to call mine the Ultimate Cart, might have to reconsider that.

 

Thanks for the suggestion on an API for saving data to file on the SD card. Though that would require games to be specially written for the cartridge...

 

Robin


Edited by electrotrains, Thu Jun 11, 2015 11:53 AM.


#14 brenski OFFLINE  

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Posted Thu Jun 11, 2015 12:37 PM

what about 

Multimate Cart ?


Edited by brenski, Thu Jun 11, 2015 12:38 PM.


#15 playsoft OFFLINE  

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Posted Thu Jun 11, 2015 12:50 PM

Hi Robin,

 

Yes the 5200 is more or less a 400 - I build for both from the same source with some conditional code. Any API would require games to be specifically written for it, but that does happen - there are a number of games written for the Atarimax Maxflash carts, some of which save to the cart. As well as saving you could load in level data from another file, effectively making a game bigger than a 8mb cart and also playing video clips etc. I guess it depends on the number of carts made/sold as to the likelihood of the API being used and of course it being something that you'd find interesting to do.

 

Paul



#16 David_P OFFLINE  

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Posted Thu Jun 11, 2015 4:56 PM

 

canvas opinion on how many would be genuinely interested

open a "poll" in the thread

 

 

  • not interested
  • interested
  • would buy

 

 

The poll options should be:

 

Yes

Heck Yes

Take my money already!



#17 Rybags OFFLINE  

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Posted Thu Jun 11, 2015 5:07 PM

Sounds good.

 

Suggestions:

. many Roms out there have no headers, so maybe allow the user to select banking type in a similar way that emulators do it.

. if it's versatile enough to support new banking schemes through reflash or dynamically then great.

. if it's got the ability to do coprocessing like the 5200 Ultimate SD cart then it'd be even better.



#18 DrVenkman OFFLINE  

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Posted Thu Jun 11, 2015 5:18 PM

I'd definitely be interested in this if it can fit into a standard cart shell. :)



#19 SS OFFLINE  

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Posted Thu Jun 11, 2015 6:53 PM

I will definitely buy this if you bring it to market.  This is exactly the product that I have been hoping to see eventually made available for the A8bit line.  Fantastic!  



#20 accousticguitar OFFLINE  

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Posted Thu Jun 11, 2015 7:06 PM

If the price were in the $60 to $80 range I imagine you could sell at least 100 of these, possibly a lot more. The thing holding a lot of people back would be that they already have a solution involving modern technology. I, for example, have SIO2PC already, but if the price were right I would certainly be interested in a SD multicart. The SD multicart would be easier to update.



#21 SS OFFLINE  

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Posted Thu Jun 11, 2015 8:02 PM

Oh, I've got a USB SIO2PC cable.  It works pretty good; the software that I use (Aspeqt) is a little sensitive about .car files though.  I would much, much rather have a SD Multi-Cart that runs ANY cartridge image!   :)


Edited by SS, Thu Jun 11, 2015 8:05 PM.


#22 MacRorie OFFLINE  

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Posted Thu Jun 11, 2015 9:33 PM

 

canvas opinion on how many would be genuinely interested

open a "poll" in the thread

 

 

  • not interested
  • interested
  • would buy

 

I am going with the already suggested: "Take my money already!"



#23 orpheuswaking OFFLINE  

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Posted Fri Jun 12, 2015 7:36 AM

Interested based on final price and ease of use. Ultimately I want to be able to dump a bunch of games on an SD card and be able to just play them from a menu. 



#24 venom4728a OFFLINE  

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Posted Sun Jun 14, 2015 7:37 PM

I am interested and would like to buy one,

 

 

Robert



#25 FULS OFFLINE  

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Posted Sun Jun 14, 2015 7:47 PM

I'll buy 2 or 3 if the "Bounty Bob Strikes Back" Rom is directly supported.

That's the only complaint I have on "The!Cart" cartridge. It supports all other Rom types.

 

Doug







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