Automatically determining the A2 slot of a specific card.

Newsgroups	comp.sys.apple2
Date	2021-10-02 22:26 -0700
Message-ID	<3ff8d7d2-dc2b-46e2-bcc8-7582d4fce86bn@googlegroups.com> (permalink)
Subject	Automatically determining the A2 slot of a specific card.
From	Lukazi <lukazi@hotmail.com>

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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.

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Automatically determining the A2 slot of a specific card. Lukazi <lukazi@hotmail.com> - 2021-10-02 22:26 -0700
  Re: Automatically determining the A2 slot of a specific card. qkumba <peter.ferrie@gmail.com> - 2021-10-03 09:02 -0700
  Re: Automatically determining the A2 slot of a specific card. ol.sc@web.de (Oliver Schmidt) - 2021-10-03 19:56 +0000
  Re: Automatically determining the A2 slot of a specific card. Charlie <charlieDOTd@verEYEzon.net> - 2021-10-03 20:44 -0400
    Re: Automatically determining the A2 slot of a specific card. Michael J. Mahon <mjmahon@aol.com> - 2021-10-04 19:15 -0500
  Re: Automatically determining the A2 slot of a specific card. R.Kiefer.SPAEM@gmx.de (Ralf Kiefer) - 2021-10-05 14:54 +0200

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