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USB dev cart project

Discussion in 'Saturn Dev' started by antime, Mar 24, 2012.

  1. duranik

    duranik New Member

    That sounds really good. Unfortunately no replay from cafe-alpha so far and
    we don´t have the skills or equipment to build them on our own.
     
  2. vbt

    vbt Staff Member

    Rockin'-B did a boot cartridge :

    http://segaxtreme.net/forum/Thread-Saturn-boot-cartridge-for-Police-Officer-Smith?t=32605

    You could write him too, maybe he is your neighbour

    Before making such boot card you can make a simple CD without IP.BIN
    and upload a binary to the saturn. It's quite easy to unlock CD access and test like that.
     
  3. cafe-alpha

    cafe-alpha Member

    Sorry, I didn't checked sx forum for a long time :/

    Sorry for the delay, but your carts are ready.
    I will send you details about them by email.


    Thank you for the advertisement :)


    USB dev cart is a good tool for testing, because you can upload 2MB (Size of HRAM+LRAM) of data in less than 10 seconds, and modchipped Saturn is not required.


    If you want "boot only" cartridge, I can build USB dev cart without USB-related ICs : it's easier (and cheaper) than building than USB dev cart.
    Boot only cartridges embed 1MB (8Mb) of flash memory. ("Regular" USB dev cart is only 256KB, but latest one is 1MB)
    If you want more space on cartridge, I can add a couple of flash chips (total 2MB, 16MB), but it would require to design a new PCB for this.

    Also, you can convert and compress Saturn executable file to cartridge firmware by using my "mkfirm" tool.
     
  4. gameofyou1

    gameofyou1 New Member

    I know this is an old post, but I have recently built some more of the USB DataLink devices (http://www.gamingenterprisesinc.com/DataLink/). You can take a look and see if this would be a useful tool for you. It requires an Action Replay cartridge with the 25-pin communication port. But you can also make use of the extra 4MB of ram in the Action Replay Cart.
     
  5. Helder

    Helder New Member

    Hi guys I'm interested in wanting to build one of these and possibly make changes by getting rid of the 2 Flash chips and use a single 16bit Flash chip instead of the 2 8bit chips with also removing some of components used in addressing of the 2 8bit chips. I plan on using a SST39VF1601C / SST39VF1602C devices (I'm aware of the voltage and plan to use a regulator) which are 1M x16 and the Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/25018A.pdf

    Basically I would like to know what I can omit in the original schematic and some help in wiring this new chip in place on the schematic and I will then make the PCB off this new schematic. Can just omitting all the components except for the Flash memory make a bare minimum cart like RockinB did? And simply wire the A and B lines to the corresponding cart edge connections?
     
  6. antime

    antime Extra Hard Mid Boss

    Using a regulator is not enough, the chip is not 5V tolerant (max voltage on any pin is Vdd+0.5V). You would need at least a 5V tolerant buffer. The rest of the ICs can be removed, there are cheap cheat carts that contain nothing but two flash ICs and decoupling caps.
     
  7. Helder

    Helder New Member

    Wouldn't using a 3.3v regulator bring the voltage down to power this chip? Also using the chip above how should the wiring go? Should A1 on cart edge go to A0 on chip? or does A0 on cart edge go to A0 on this chip?
     
  8. antime

    antime Extra Hard Mid Boss

    The Saturn will still drive the I/O pins with 5V. The M29F/MX29F series should be suitable. In the schematics for the USB dev cart, the address bus is already offset by one so pin A45 on the edge port should be connected to A0 on the flash IC.
     
  9. Helder

    Helder New Member

    Ok I decided to go with a 5v tolerant memory IC (MX29F160) and I know I have some errors on the schematic but would need to have them pointed out to me if you could take a look at the schematic I have. Please point out what needs to be fixed or dis/connected, thanks in advance.

    http://postimg.org/image/4otlkf9nv/full/
     
  10. antime

    antime Extra Hard Mid Boss

    The RESET# pin must be pulled high. You should also add a 0.1µF decoupling capacitor, as recommended in the data sheet. Place the capacitor as near to the IC as you can.

    As I mentioned earlier, what you're designing is very close to the basic unlicensed backup memory carts, so if you run into problems you could also give one of those a shot. Even if you don't, they're a relatively cheap source for cartridge shells.
     
  11. Helder

    Helder New Member

    Well the whole thing behind this is a bootup cart that Cyber Warrior X (he's a member here) coded as a replacement flash update for the AR/GS carts which uses an exploit that was found recently after the CD Block was fully dumped. I hate to ruin the functions of my AR 4+ so I wanted just a standard cart to do this. I'm not sure this info is here on this forum or not but here is the link to the thread. Oh and thank you for looking at the schematic and giving me some tips.

    http://www.assemblergames.com/forums/showthread.php?52526-Saturn-proof-of-concept-bootloader-Pseudo-Saturn

    Edit: Do you happen to know how to copy the outline of the pcb from one project to another in kicad? Somethings that should be simple and available I find is missing or lacking in kicad (I use eagle for most designs I do).
     
  12. antime

    antime Extra Hard Mid Boss

    CWX's program has nothing to do with the CD block being dumped, he said himself that he had been working on it before. It's also not a new idea, Rockin'-B used the same basic idea to load data burned as audio CDs. Full credit to CWX for actually implementing it though. There's also no exploit as such involved, it uses designed functionality of the Saturn.

    You can get basic AR clones without the RAM for less than ten bucks, but whatever. Their reliability may also not be the best.

    I don't think you can copy arbitrary layers in KiCad, you'd probably have to make a part, like the edge connector. The design also just uses the back silkscreen layer for the outline, as the manufacturer I used didn't accept a separate outline layer file.

    By the way, the Panzer Dragoon Saga patch mentioned in that thread was developed here.
     
  13. Helder

    Helder New Member

    Ah I see, I was unaware that it had been implemented and figured it progressed to the current stage it is in now because of the CD block being dumped. A quick question: What should be the minimum Memory Size for my project 1Megabit?
     
  14. antime

    antime Extra Hard Mid Boss

    That depends on how much space you think you'll need. I can't answer that.
     
  15. Helder

    Helder New Member

    Ok more question, can I use the SST39SF040 in place of the SST39SF010 on your board? I see that the one I want to use has 2 extra address lines A17 and A18 and wondering is it ok to leave them not connected aka floating? or will the have to be tied to ground?
     
  16. cafe-alpha

    cafe-alpha Member

    You can use SST39SF040 and consequently get 1MB Flash space if you connect A17 and A18 to their respective address lines on connector.
    I'm already doing this with my cartridges, and I do confirm it works.

    Floating input is not recommended, so you should connect to GND. But in this case, you would better use SST39SF010A chip.
     
  17. antime

    antime Extra Hard Mid Boss

    Digital inputs should never be left floating.
     
  18. Helder

    Helder New Member

    Ok thank you guys for the reply and info. I had an interest in flashing the AR firmware on these but ultimately I don't think there is any cheat tool that used to exist that will interface with the USB. Do you guys know of a way to get it to interface with hacking tools like GSCC2002 without a complete software rewrite maybe some code modification to accept USB?

    I can wire in the A17 fine with no issue but the A18 is going to Pin2 A0 on the 74HCT245 , do I remove that pin connection or do I leave it as is but connect the A18 pin from flash to the connector A18?
     
  19. cafe-alpha

    cafe-alpha Member

    In the case you modify antime's USB dev cart, you need to modify some wiring around U1 and U2 : antime's version maps devices by step of 512KB (A18/A19/A20 connected to U2) while you need to map by step of 1MB (A19/A20/A21 connected to U2).
    Consequently, AA18 don't need to be connected to U1 and you can directly connect it to your flash chips.
    Please refer to this schematics for details.

    BTW, how many PCB do you need ?
    I plan to order some PCB soon, so if you need only a small quantity (1-3 piece(s) or so), I can post them to you if you want :)
     
  20. Helder

    Helder New Member

    Thanks for explanation and schematic picture, I only need 1 pcb as of now to see if it will work for what I have in mind. I don't need any components as I can solder those on without issues.
     

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