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pcrock

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Posts posted by pcrock

  1. Posted

    3 hours ago, alex_79 said:

    Those roms were modified to run on this board, because it implements a different bankswitching scheme compared to the original games.
    They access address $FA0 for bank 0 and $FC0 for bank 1.


    If you want to program the eprom with different games, you'll need to modify the roms as well for use with this board.

     

    Stella doesn't yet support this as there were no known roms using these hotspots addresses before.

     

    I drawn a schematic of the bankswitching logic using your pictures as reference (I had to guess a couple of connections, as some traces are not visible without desoldering the two logic ICs, but I'm quite confident that this is correct.

    It's very similar to the scheme used in this other board (from brazil too), but this one uses more address bits, so the hotspots are a subset of those that trigger the bankswitch on that other board.

     

    board.thumb.jpg.fac949c946a8bb2c9e66dc7d520c719b.jpgschem.thumb.png.06fe8d7b02d027a6201bdfb715f89e4c.png

     

     


    Any address with A12=0, A10=1, A9=1, A7=1, A6=0, A5=1 cause a switch to bank 0
    Any address with A12=0, A10=1, A9=1, A7=1, A6=1, A5=0 cause a switch to bank 1
    Any address with A12=0, A10=1, A9=1, A7=1, A6=1, A5=1 may or not cause a bankswitch (undefined state of the NAND SR latch).

     

     

    Thanks for sharing the dumps and pictures of the board!

     

    Wowww!! Very thanks!! I have no words to thank you alex_79 !!!

    I will remove the two ICs and post a picture to you ensure that all is ok!!

    I am very sad about different bankswitching scheme in my circuit compared to the original games.

    I can't understand. Why they do that instead to use original game schemes?

    I did put a zif socket at this cart cause I did plan to use a lot of 27Cxxx with 8K games but is impossible to me modify originals roms to work with this cart! I don't know how to modify games. I would love to learn how but it appears to be very hard and complicated to me. 

    Please let me know friend. Is possible to modify my circuit to became it able to work with original roms (mainly BeamRider, Pengo, Galaxian and Centipede)  or does exists any other way (like a software for exemple) that could modify the games for me?

    Sorry if I boring you but I don't know much about programming (to tell you the truth I do know very very few)

    Once more special thanks. 

  2. Posted

    Another doubt I have is:
    The original dump I did (attached here) from the working cart does not works on Stella Emulator but works perfect in the cart. 
    What is the reason?
    I tryed to extract the first 8K from the original dump file (that I supose to be a game) and create a new file but that new file still not works on Stella.
    Why the dump file from original eprom works in the cart but does not in the stella??
    Thanks

  3. Posted · Edited by pcrock

    Hi friends.

    I have a 2 in 1 cartridge with two 8K games that works PERFECT. The games are HERO (by Mania) and KUNG FU MASTER (by Activision \ Irem).
    The circuit uses two ICs 74ls00 and 74ls10 and the Chip is MBM27128-30.
    I did the dump file to backup and I sent it here at the post.
    I would love to create a new BIN file with BeamRider and Tapper. But when I created the new eprom with that games I want, the cart does not work.
    I tryed to create eproms with anothers games like Tapper and Pengo or Galaxian and Centipede but still never works. 
    I also tryed to create roms with four games to use in another 4 in 1 8K games I have but not works too!!!
    There are some matter with bankswitch???
    Is possible I make a 2in1 or 4in 1 roms with the games I want to run on my carts??
    Thanks friend
     

    WhatsApp Image 2020-09-04 at 23.16.39 (3).jpeg

    WhatsApp Image 2020-09-04 at 23.16.39 (2).jpeg

    WhatsApp Image 2020-09-04 at 23.16.39 (1).jpeg

    WhatsApp Image 2020-09-04 at 23.16.39.jpeg

    WhatsApp Image 2020-09-04 at 23.16.40 (1).jpeg

    WhatsApp Image 2020-09-04 at 23.16.40.jpeg

    MBM27128-30_ HERO by Mania RJ_KUNFU MASTER By Irem Activision.BIN

    • Thanks 1

  4. Posted

    11 hours ago, Danjovic said:

    Word "solda" on the board delivers the this is a cartridge from Brasil. You can also see missing diodes, probably part of decoding logic left aside.

    There is a chance that you can combine the counter and the logic to have a standard bankswitch. If you can get the eprom out and read you can compare the binary with the original games and check if the bakswitch is a standard one or if the games were hacked.

    If you ever dismantle the board to investigate that, please take some pictures and post here so we might trace the circuit.

    Yes friend! That is a Brazilian cartridge. Here in Brazil, due the parts costs, there were a LOT OF TRICKS to turn the things cheap!! Here we have things like four 8K games in a 27128 chip (as posted in another post) and more!!!
    I WILL TRY remove the chip from PCB and post some pics here!!!
    Thanks for replying.

  5. Posted

    14 minutes ago, batari said:

    The '4040 chip is a 12-bit ripple counter so there are potentially up to 12 outputs here you might be able to use for the upper address lines of the EPROM to add more games.

     

    Unfortunately, though, I don't think the games themselves are unmodified, as there is not enough logic there to support F8 bankswitching, so you would need to modify other games to work with whatever banking this supports.

    Thanks for replying.
    I don´t know to modify Roms to do that. I think what I want to do is a bad idea so...
    Even If I use an other 27128 to use only two games and to burn 2 any 8K roms inside the new chip it still will not work if the roms need to be modified...

  6. Posted

    47 minutes ago, Kroko said:

    Without looking at the circuit, I doubt that it will work. What the circuit has to do is to select the highest address line on the EEPROM to select one of two 8K areas inside your 16K chip.

    If you want more than 16K to have more than two 8K games, you will need
     

    * a larger chip which may have a different pinout => you may need some kind of adapter
    * need a strategy to control the higher address lines because most likely your device is not doing this (you could use simple switches for that to set the high address lines to 0 or 1)

    Then by cycling the power you would select between two 8K roms. By the switches you could switch in two different ROMs.

    I plain to use 27C256 or 27C512. All of then appears to be compatible with 27128. Are this correct??

  9. Posted

    On 8/24/2020 at 8:50 PM, Shawn said:

     

    Willem programmers are the bottom of the barrel but they do work for what they are. For only a couple bucks more you can get a TL866 as mentioned a couple times in this thread. The TL866 and any of it's variants\successors are far superior to those entry level Willem PCB only programmers. 

    I do agree with you but in Brazil a TL866 costs much more than a couple bucks. It is a very expensive device.  
    The Willem is the bottom of the barrel but to work with 27XX chips it works good and fast.
    If wou want to program all others varieties of chips then the Willem is not good even.

  10. Posted

    Hi friend. I own this cart with Two 8K games in (Ms. Pac Man  /  Donkey Kong Jr.).
    To select the game you want to play you need to turn off and, after, turn on again the console.
    The circuit uses 2 ICs (HCF4040BE and 74LS00BI) and a transistor that I think is a NPN one.
    he Eprom is HN27128AG-25
    My question is:
    What will happens if I put a zif socket and try a 27C256 with four 8K games inside it or if i use a 27C512 with eight 8K games inside???
    Would Work??
     

    8Kx2_frente Atari.jpeg

    8Kx2_frente b Atari.jpeg

    8Kx2 Atari.jpeg

  11. Posted

    On 8/23/2020 at 11:09 AM, ClausB said:

    The original chips are called mask ROMs. The data are built in at the factory. They can be built with active high chip select lines so they don't need the inverter. In the Atari 2600 the ROM chip select signal is simply A12 from the CPU. When A12 is high then the ROM is active and when it's low the other chips are active. 27xx EPROMs are made with active low chip select inputs, so you need to invert A12 for those. The game code does not have to be changed to put it into an EPROM.

    Very very thanks friend for be so patient with me and my asks!!

    • Like 1

  13. Posted

    What is the reason we need to do this trick to use 27XX in original Atari cartridges???
    The originals chips is not a real 27XX ?? How the original pcb does not uses any additional circuit to work but we need to put an inverter to???
    If the original chips is not a 27XX, how was it dumped firstly? Were The original rom games modified to work in 27XX ??
     

  15. Posted

    13 hours ago, ClausB said:

    The original modification works for the 2732 and the new modification for the 2716. 

     

    In your first post you said the 2732 worked and the 2716 did not, so I suggested a mod for the 2716. If you want the board to work with either, then add a switch to pin 21.

    Finally all SOLVED.
    I found that ClausB is RIGHT!!!!

     

    It happens that some kind of 2716 works fine with the pin 21 connected to A11 but some NOT!!!
    I have several brands and kinds of 2716 chips here and tested all with my cart. All of then works good but some chips works fine with pin 21 connected to +B and works fine with pin 21 connected to A11 too but some chips ONLY WORKS if pin 21 is connected to +B 5V!!
    So, as sayd ClausB, I will need a switch to correct run any kind of both 2716 and 2732.
    I have no words to thank you friend.

    • Like 1

  17. Posted

    10 hours ago, ClausB said:

    The original modification works for the 2732 and the new modification for the 2716. 

     

    In your first post you said the 2732 worked and the 2716 did not, so I suggested a mod for the 2716. If you want the board to work with either, then add a switch to pin 21.

    Thanks for replying. I thinked that would work to both 2732 and 2716 the same circuit. So I will must to include a switch. Very thanks again. 

  18. Posted

    On 8/4/2020 at 5:29 PM, ClausB said:

    If you have already modified the board as above, then cut the bare wire to pin 21 and jumper a new wire from 21 to 24 as below. If you have not yet modified the board, then do not cut the trace between 21 and 24 and do not add the bare wire to pin 21.

     

    2716.jpg

    Hi friend. I did the above circuit exactaly as you sugest. I used a smd 74LS04  and the device works PERFECT with both 2516 and 2716 ones!!
    But I removed a HN482732AG-25 from a working RIVER RAID cartridge and did an UV erasing. After the erasing process I did a Blank Test and the software says BLANK CHIP OK! So I burned it in with the MOUSE TRAP NTSC ROM (I am sending it attached this message) and the programming process ran everything ok. When finished, the system checked the file and the eprom

    content match the file all ok!
    But when installed the eprom in my cartridge, it does NOT WORK !!! 
    I tryed several times but it never works!!!!
    So I dump the file from the not working chip and try it in the Stella and the dump file works great!!!!
    What is wrong????
    Why my device works with 2716 but NOT with 2732 ???
    Please help me.
    Thanks friends!

    TESTE MOUSE TRAP.BIN

  20. Posted · Edited by pcrock

    On 8/10/2020 at 3:18 AM, Carlos Baldo said:

    Oi pcrock, obrigado pela resposta.

     

    Meu Atari Jr. europeu tem um chip UM6526P1 8850S. Porém, modificá-lo para NTSC mudará a paleta e fará com que o console se comporte exatamente como o nosso Ataris brasileiro, certo? Se isso for verdade, vai anular todo o propósito de usar um Atari europeu. Há um punhado de jogos que são lançados apenas na Europa ou seus equivalentes de 50 Hz são muito mais baratos do que os de 60 Hz. Essa é a principal razão pela qual tenho este console, para jogar jogos europeus.

     

    Não entendi, PAL-B e PAL-N são o mesmo sistema de TV em cores. A diferença entre eles reside apenas na frequência da subportadora de cor durante o uso de vídeo composto. É por isso que as TVs na América do Sul geralmente detectam PAL europeu como PAL-N e, como consequência, não conseguem recuperar nenhuma cor do sinal. Deve ser fácil converter um console PAL-B para o sistema PAL-N, mas ainda não tive sorte ao tentar fazer isso. ☹️

    Sorry friend.
    I misunderstood your desire! 
    Yes. if you turn your console in a NTSC version it will work jus like the brazilian ones.
    So you want to turn the PAL-G version in a PAL-N version. Is this right?
    I have an old VCR Recorder (Panasonic J-48) that works as a PAL-N to NTSC transcoder but due 60HZ Brazilian system, the screen blinks what make a boreing experience to watch PAL-N here.
    But that is another talk to another time...
    I think that what you want to do is not an easy task.
    Do you have a PAL-N TV in Brazil???
    All of mines can work in NTSC and PAL-M versions but NOT in PAL-N

  24. Posted · Edited by pcrock

    Hi. I Live in Brazil too. Please tell us the main CHIPS numbers used in your console (Does it uses 6526N and 6532G ones??, I think it does not). 
    UM6526P1 9134S -- Found in a PAL-B 2600 JR and UM6526P1 9212T -- Found in a PAL 2600 JR, Rev F.1.1.
    If your unit uses one of that chips numbers, it could to have a little different pinouts. (I Think) Is possible to modify your unit to NTSC version, that today is a very easy to use system, even in Brazil. But maybe you will have an effort to do that.
    I can write in Portuguese if you want.

  25. Posted

    Hi friends.
    I have a huge question and I'm very curious about how it is possible.
    I own an Atari 2600 cartridge that contains four 8K games. 

    They are:
    PRESS COOKER, E.T., ROBOT TANK and PIGS IN SPACE. (4 x 8K = 32K)
    All of it is 8K games each one so the minimum chip to fit that four games, I THINK it would be a 27C256 but as you all can see the chip used is 27C128 , that I think fits only a 16K program!
    How is it possible?????
    I would like to understand that magic. I have interest on doing my own 8k cartridges.
    Could any friend explain to me?

     

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