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Thread: [GUIDE] Make a Reprogrammable Genesis Cart

  1. #211
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    Quote Originally Posted by Jazzmarazz View Post
    Thread opened by request.



    Sorry I never responded. I must have missed your post. The double posting rule pertains to short periods of time between posts. If no one seems to respond within a week or two, feel free to double post. Also feel free to PM me directly. I like to keep all discussions in this thread for others to find, but I may not see every post even if I would like to.

    Really glad you got your Cotton cart working on your own, you must have learned a bit from that experience.

    As for PS4, it sounds like you are using two different "types" of saving-boards. PS4 uses a large SRAM chip while the original Wily Wars uses a small EEPROM to save. These are not compatible with each other however, There is a patch for the Wily Wars ROM that changes it to use SRAM instead. This makes it compatible with SRAM type boards.
    Yes I just came to the conclusion that PS4 and similar donors must just access save data from different locations within the rom and that is why they are not compatible for saving. As far as Cotton goes it was a learning experience doing pin traces but the game that really required learning was making Golden Axe 3.

    That game has region protection so good that it required me to learn how to put a game genie master region code into the rom using a hex editor. Not only do you have to get the code but you have to convert it to hex and then open the rom and put that hex code into the rom. While not all the difficult once you do it, having no idea what hex code is or ever using a hex editor you are basically flying blind and hoping for the best.

    I have so many of the EA games that are good save donors but I don't have any games that would require a big shell like that and I personally don't like the looks anyhow. Any interest here I plan on unloading them on ebay.

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    Quote Originally Posted by icemanxp300 View Post
    Yes I just came to the conclusion that PS4 and similar donors must just access save data from different locations within the rom and that is why they are not compatible for saving. As far as Cotton goes it was a learning experience doing pin traces but the game that really required learning was making Golden Axe 3.

    That game has region protection so good that it required me to learn how to put a game genie master region code into the rom using a hex editor. Not only do you have to get the code but you have to convert it to hex and then open the rom and put that hex code into the rom. While not all the difficult once you do it, having no idea what hex code is or ever using a hex editor you are basically flying blind and hoping for the best.

    I have so many of the EA games that are good save donors but I don't have any games that would require a big shell like that and I personally don't like the looks anyhow. Any interest here I plan on unloading them on ebay.
    Hahah, hex editing can be daunting. Would you like to upload the modified version of your Golden Axe 3 ROM? I think someone could find it useful. I have never tried getting taht one to work.

    I know what you mean about the large EA carts. They are pretty ugly.

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    Quote Originally Posted by Jazzmarazz View Post
    Hahah, hex editing can be daunting. Would you like to upload the modified version of your Golden Axe 3 ROM? I think someone could find it useful. I have never tried getting taht one to work.
    I can do that, I have got plenty of files from this site. How do you upload it and make sure people know it is a region bypassed version? Here it is, if someone wants it.

    GA3RB.zip
    Last edited by icemanxp300; 3rd-February-2017 at 04:35. Reason: adding file

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    Quote Originally Posted by icemanxp300 View Post
    I can do that, I have got plenty of files from this site. How do you upload it and make sure people know it is a region bypassed version? Here it is, if someone wants it.

    GA3RB.zip
    Thanks a lot. It looks like the checksum in the header is incorrect though. At least, Kega Fusion says so. What system or version did you run this on? Genesis model 1, 2, 3, Nomad? I think the model 1 and 2 would just display a red screen if the header wasn't fixed. I'll go ahead and fix it in the morning, Im just curious.

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    I test all my games on a tmss model 1. You are correct the checksum was bad. I must have missed that. I generally fix them all.

    Here is a fixed checksum.

    GA3RBFC.zip

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    Hay jazz can check this out tell me what you think thanks in advance .. been trying to make SMB for the Sega Genesis and am not having much luck. The game is 64KB big and I'm suing one of my boards and a 322. So far sprites display and lately the top half of the screen displays. I've tried 'fixing' the checksum and have been stumped so far as to what the issue is. 16427403_1979251898971104_7692601677540778090_n.jpg 16602492_388452951516701_5360164678297588177_o.jpg Capturedsd.PNG Heres ROM used Download Links:
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    Quote Originally Posted by killapinke View Post
    Hay jazz can check this out tell me what you think thanks in advance .. been trying to make SMB for the Sega Genesis and am not having much luck. The game is 64KB big and I'm suing one of my boards and a 322. So far sprites display and lately the top half of the screen displays. I've tried 'fixing' the checksum and have been stumped so far as to what the issue is. 16427403_1979251898971104_7692601677540778090_n.jpg 16602492_388452951516701_5360164678297588177_o.jpg Capturedsd.PNG Heres ROM used Download Links:
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    I read that facebook post and I thought they said it was working on a different Genesis. It sounds like a coding problem which I couldn't help with.

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    Yeah it works I'm just trying to figure out why it works on some systems and not others.

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    Quote Originally Posted by killapinke View Post
    Yeah it works I'm just trying to figure out why it works on some systems and not others.
    Maybe some of the consoles have TMSS and others do not? Are all of the Genesis consoles official and not clones?

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    Hi,

    Just wanted to experiment with this a bit. Picked up a few games to test with, but in this case I'm using NHLPA Hockey 93 as the donor cart (512Kb) and trying to use a M27C322 EPROM. The game I'm testing with is Rockman Mega World (Japan). The burns are good, verified the ROMs after burning, using a GQ-4x (latest model). Running this on a non-TMSS Genesis 1.

    This board is strange; the front-facing part of the board is labeled A1/A32 on the cartridge pins. The original cart has the ROM facing towards the front of the system when inserted.

    Here's some photos of what I'm working with.

    http://imgur.com/a/gLaen

    This is a 40-pin board, but had two pins on the far left side (ROM side) that were not connected to anything. I put a 42-pin socket in place, but noted that I would need to place 40-pin EPROMs all the way to the right (ROM side). I tested with the original ROM inserted all the way to the right and the cart works.

    I tried first with the M27C322 socketed this way and wired pins 1/42/32 of the EPROM to the back side of the PCB (remember that the top/ROM side of the board is labeled A1-A32). That didn't work at all. I tried a few different variations (you can probably figure out what I tried based on the photos), but no luck.

    What am I missing, or is NHLPA Hockey 93 just the wrong board to be trying this on?

    I would expect to get something (corrupt graphics, etc) but when I power on the system, I get nothing but a blank screen.

    Thanks for your help!

    EDIT: Decided to try Wonder Boy in Monster World (USA, 1 megabyte) on M27C322; NHLPA Hockey 93 donor board. Wired only A19/A20 to B8/B9 (see photos). Still no luck, just a black screen.
    Last edited by wavebacon; 19th-March-2017 at 07:07. Reason: Tried Wonder Boy

  12. #221
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    I am fairly certain that the board itself is labelled wrong. I have come across one of these before. Even though the front side of the board is labelled the 'A' side, it is not. Do not solder the address pins to the back side of the board. Treat it as if the front is the B-side.

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    Quote Originally Posted by Jazzmarazz View Post
    I am fairly certain that the board itself is labelled wrong. I have come across one of these before. Even though the front side of the board is labelled the 'A' side, it is not. Do not solder the address pins to the back side of the board. Treat it as if the front is the B-side.
    Hm, no go with the wiring swapped to the other side. Check out the cart/board/wiring:

    http://imgur.com/a/P2wgu

    So some things I noticed about this board:

    B7 is already connected to A18 on the EPROM, so no wire was needed
    B8 is connected to pin 13 of a T74LS139B1 labeled "U3"
    B9 is connected to pin 3 of a T74LS139B1 labeled "U3".

    I ran wires from B8 to A19 (pin 42 on the EPROM) and from B9 to A20 (pin 32 on the EPROM). Adding the wire from B9 to A20 connects B9 to the +5V line (is that correct?)

    Any ideas on this one? I picked this board because it was in your list of Serial-EEPROM games, but at this point I'm tempted to toss it in the trash.

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    Hmm... I see a few problems here, and I do that know how useable the board it's going to be. First of all the address pins of the eeprom cannot be connected to any other logic. That goes for pulling a 20 high as well. In doing so you basically eliminate the lower half of the eeprom entirely. The higher half or "Bank" of the eeprom will be enabled at all times. Which means if the data is in the lower Bank it will never be accessed.

    As for the other two address pins, it seems they are already used in switching between ROM and RAM by the original hockey game. What that means is that if you would like to use this board for a much larger game you may have to reroute many of the pins.

    A more detailed explanation is that the original hockey game used the first one megabyte bank for eprom and has the second one megabyte hard mapped to the ram. So unless you rerouted the address outputs from the cartridges Edge then your second megabytes of ROM is going to overlap the. I think at this point, a new donor board will do you good. Keep this board for a smaller game though.

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    Quote Originally Posted by Jazzmarazz View Post
    I think at this point, a new donor board will do you good. Keep this board for a smaller game though.
    Awesome, thanks for your help! This is a really fun learning experience. I thought something about this board seemed funny. Luckily I picked up a bunch of sports games for <$1 each to play with this.

    So for my clarification, I should be able to use this board with 27C400 (40-pin 512KB) but not 27C800 (42-pin 1MB) EPROMs? Or will either be fine?

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    Either should be fine. If you really want to get the 27c320 working, then you will have to disconnect B8 and B9 from U3. Then connect them to the properties on your eprom. Also, make sure that no other pins are bridged, so vcc cannot be connected to any address pins. It would be easiest to lift the two address pins out of the holes and solder them with wire that way.

    Doing so will disable ram though

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