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

Message
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

Other related posts: