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Thread: Differences in PROG and CHA board types?

  1. #1
    . avramce's Avatar
    Join Date
    Sep 2019
    Seattle, WA


    Differences in PROG and CHA board types?

    Hi all, had a fun holiday season and decided to tear down all the spare/bootleg carts I've collected in the last few months, and ended up with the following:
    1x PROG42G-1
    1x PROGTOP
    3x PROGBK1

    1x CHA42G-1
    4x CHA256

    I decided that I'm going to try my hand at making a Ghostlop, Ironclad and Crossed Sword 2 carts given they weren't commercial available (not available on a 161 cart afaik). I have been reading up on the neogeodev wiki and have a general understanding of the idea of the M1/S/V/C/P roms, but cannot find concrete info on stuff like why certain boards have to be used with certain games.

    Going off the boardcodes list on JNX, I thought my Crossed Swords 2 cart would end up using the 42G-1's I have, but the board pics on MVS-Scans used a BK1+256 combo. Is there any reason for this other than the general availability of the BK1+256? Likewise, the Ghostlop pics use a GCS+256 combo, does that mean that I cannot use a BK1 board for that game?

    Also, I've been trying to wrap my head around the jumpers and ROM divisions. I understand the more straightforward use of a 32Mbit rom for a V1 (as seen with Ironclad), but I noticed the MVS-Scans pic has two 16Mbit roms for V1/V2 instead. Other than splitting the ROM into equal parts, is any other setup required to use multiple chips? Like with Ironclad, the game has 4x32Mbit C-ROMs, is there any reason that I couldn't get away with 8x16Mbit ROMs?

    Lastly, I recall reading on the board something around the lines of "swapping pins" for the S or M1 roms - where does that play a role? Is this regarding the usage of a 28-pin dip vs a 32-pin? Or are there peculiarities with certain games that the address pins have to be grounded or tied together?

    Any help or information would be greatly appreciated. At this point, I tried to create an Ironclad on a BK1+256 setup, and got the game to boot with garbled graphics/sound. I assume that I failed when programming the ROMs, but figured I might have missed something more basic with understanding how the jumpers and board-types play a role.

  2. #2
    Mr Big's Escort
    shadowkn55's Avatar
    Join Date
    Dec 2006

    The main differences between the boards is the amount of memory they can address. For the boards that have jumpers, it is to configure how large of an eprom is going to be accessed.

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