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   comp.sys.apple2      Discussion about Apple II micros      56,720 messages   

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   Message 55,024 of 56,720   
   Lukazi to All   
   Automatically determining the A2 slot of   
   02 Oct 21 22:26:15   
   
   From: lukazi@hotmail.com   
      
   Cards which contain memory (ROM) are easy to be made auto detectable because   
   the memory can be programmed to output a specific identifier to the peripheral   
   slot memory locations ie $C0XX. However it is much more difficult to detect   
   cards that do not    
   contain any memory chips.    
      
   The 4Play card is detectable because of luck. The unique pattern it generates   
   by default produces $20, $20, $20, $20 for locations $C0X0 to $C0X3. So this   
   is also easily read by the A2 to determine the slot.   
      
   However cards such as the SNES MAX do not produce any output until they are   
   asked to do so ie poking addresses to determine what you get back. Therefore   
   my questions are:-   
   Is is ok to poke each peripheral slot in an attempt to determine a cards   
   identity?   
   Does this have the potential to screw up the setup on other slotted cards (I'm   
   thinking about I/O cards because poking will be driving physical external   
   devices)?   
   Was there a best practise guide between developers for doing this?     
   Is there consolidated information anywhere on how A2 auto slot detection of   
   cards was performed?   
      
   Thank-you for your help.   
      
   Cheers,   
   Alex.   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)   

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