[atari7800] Re: [personal] Re: AW: 7800 cartridge detection

MessageYes, I think you are right. I tested it with connected Krokodile Power 
supply. It still runs Asteroids.
And if the Power supply is connected, the Krokdile is active before the 7800. 
So that can't be the
problem.


  ----- Original Message ----- 
  From: Dan Boris 
  To: atari7800@xxxxxxxxxxxxx 
  Sent: Thursday, August 11, 2005 2:28 AM
  Subject: [atari7800] Re: [personal] Re: AW: 7800 cartridge detection


  I guess it's possible the 7800 has a shorter power on delay, but it still 
have to run a couple hundred machine cycles before it gets to the validation 
routine, so it seams unlikely that your cartridge isn't powering up in time. 

  Dan
    -----Original Message-----
    From: atari7800-bounce@xxxxxxxxxxxxx 
[mailto:atari7800-bounce@xxxxxxxxxxxxx] On Behalf Of Kroko
    Sent: Wednesday, August 10, 2005 6:57 PM
    To: atari7800@xxxxxxxxxxxxx
    Subject: [atari7800] Re: [personal] Re: AW: 7800 cartridge detection



    I was planning to make the Krokodile Cartridge run on a 7800. I plugged in 
4 different firmware revisions, even different
    board versions which all run 100% OK on my 2600. But all I get in the 7800 
is Asteroids :-(

    So I need to find out why a 7800 would decide to run Asteroids instead of 
running an ordinary PacMan Rom programmed on a
    Krokodile Cartridge ... I think that info you just posted already helps:

    Could the startup time be a problem ? As there is a microcontroller on the 
Krokodile, it is not 100% "instant on". maybe the 7800
    starts up more quickly than a 2600 and checks the cart slot at a time where 
the Krokodile is not yet ready. Is the 2600 slower ?!

    Well, just a first guess ...

    I don't think its a dirty slot, because I have quite some 2600 Roms which 
run normally (including PacMan) ...

    Armin

      ----- Original Message ----- 
      From: Dan Boris 
      To: atari7800@xxxxxxxxxxxxx 
      Sent: Thursday, August 11, 2005 12:35 AM
      Subject: [atari7800] Re: [personal] Re: AW: 7800 cartridge detection


      This discussion got me thinking that I never actually looked at the PAL 
BIOS disassembly. So i did a diassembly and have been trying to figure out how 
it works. Here's what I have found so far..

      The BIOS compares FE00-FE7F with FE80-FF00 and if they are the same, it 
assumes there no cartridge and jumps to internal game. 
      Next if checks the reset vector, and if it's $FFFF or $0000 then it 
assumes there's no cartridge and jumps to the internal game.

      It looks like it then checks $FFF8 and $FFF9 for a valid 7800 cartidge 
header. If it's not valid it starts the cartridge in 2600 mode.

      That's all I have been able to figure out so far.

      Dan

        -----Original Message-----
        From: atari7800-bounce@xxxxxxxxxxxxx 
[mailto:atari7800-bounce@xxxxxxxxxxxxx] On Behalf Of Kroko
        Sent: Wednesday, August 10, 2005 5:18 PM
        To: atari7800@xxxxxxxxxxxxx
        Subject: [personal] [atari7800] Re: AW: 7800 cartridge detection


        Do you know, how the 7800 detects if a valid cartridge is plugged in ?

        ----- Original Message ----- 
          From: Matthias Luedtke 
          To: atari7800@xxxxxxxxxxxxx 
          Sent: Wednesday, August 10, 2005 11:09 PM
          Subject: [atari7800] AW: 7800 cartridge detection


          If you have trouble with more than one cartridge than I guess your 
7800 have a problem.

           


----------------------------------------------------------------------

          Von: atari7800-bounce@xxxxxxxxxxxxx 
[mailto:atari7800-bounce@xxxxxxxxxxxxx] Im Auftrag von Kroko
          Gesendet: Mittwoch, 10. August 2005 21:16
          An: atari7800@xxxxxxxxxxxxx
          Betreff: [atari7800] 7800 cartridge detection

           

          Hi !

           

          I am having trouble with a 7800. How does the 7800 detect that a 
cartridge

          is plugged into its cartridge port ? It starts up the built in 
Asteroids for some of

          the cartridges I have here, even if they are plugged in ...

           

          Is the 7800 faulty or the cartridges, or is this a common problem ?

           

          Armin

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