Jump to content

zx-81

Members
  • Posts

    7
  • Joined

  • Last visited

Posts posted by zx-81

  1. You should get a menu to select the games at power up.

    It happens that at power up, a game is started (instead of the menu). I have seen that on adam computer, but not on coleco.

    If it is always the same game that is started, then you can always put the rom menu at that particular location in the address space of the eeprom.

    If it is random, then it might be a faulty pcb or bad solder.

    What i have seen as well is a faulty transistor (or wrongly soldered, with drain and source swapped). In that case it can also provide a wierd boot screen with colecovision letters and random characters below.

  2. @OriginalJohn : For the parts i have used the following :

    - 74HC574D

    - 74HC688D

    - 74HC541D

    For the resistor 10k Ohms and for the Transistor model i have used is a BS170.

    Be careful that some of the BS170 may have the drain and the source swapped compared to what is used on the 63in1 PCB.

    The symptoms are simple in that case : when you select a game from the first bank, it is actually failing as if you had no cartridge inserted (boot logo of colecovision with the message of the missing cartridge).

    The solution is just to swap the transistor or to solder it on the other side of the card.

     

    @Fabriciotm

    Yes, i know that issue, actually i had to modify manually those roms (Pacman, Popeye, etc ...) to be compatible with the 63in1.

    In those games, they are accessing the address range 0xffc0 to 0xfffe  that we are using for the bank switching and it is messing up everything.

    What i did is to modify those roms to relocate the portion of data located in that address range and to move it somewhere else in the rom and to modify the binary code accordingly.

     

    You can PM me if you need more information.

     

     

  3. I tried to contact the designers but they won't respond...

    I do not know enough about electronics to understand what happens there. In fact, I was wondering whether that behaviour depends on hw or sw. From what you write, it depends on hw and I can't do anything in the loader code to modify it. Correct?

    Hi zCRP,

    We didn't put in place any reset mechanism to return to the menu. You have to switch off/on the console to get the menu working.

     

     

    I made this cartridge today and try to use the example roms without success. Mi CV boots on Jungle Hunt and not in the loader's game list.

     

    Could you explain how to make this rom files step by step?. I don't have a clue about scripts.

     

    All you need is on the 63in1 file.

     

    Thanks in advance.

    Hi Querubin,

    The loader is located in the last 32k block of the second eprom (so at the end of the total address space of the two eproms).

    If Jungle Hunt starts (located at position 31), and you have flashed properly the two binary files properly, then there is most likely an issue with the selection between the two eproms

    (as if the clock enables of the two eproms were not properly working).

    So i will look at the PCB :

    - the pin 14 of the 74HC574D

    - the Clock Enable of the two eproms (pin 22)

    - the transistor BS170 used to do an invertor

×
×
  • Create New...