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mg_notes:iie_card:problem_software [2019/10/14 03:53]
M.G. [LC //e Card - Problematic Software]
mg_notes:iie_card:problem_software [2019/10/14 03:59] (current)
M.G. [Software That Uses the Floating Bus]
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 Other software may produce unexpected output on the screen depending on how it uses the disk, or if it uses DGR graphics. ​ Other software may produce unexpected output on the screen depending on how it uses the disk, or if it uses DGR graphics. ​
  
-===== Bitsy Bye =====+===== Bitsy Bye in ProDOS 2.4.0 and 2.4.1 =====
  
 Bitsy Bye, as included with ProDOS 2.4.0 and 2.4.1, accidentally access $C029, switching out the main ROM bank.  This causes a crash when it tries to use a firmware routine. Bitsy Bye, as included with ProDOS 2.4.0 and 2.4.1, accidentally access $C029, switching out the main ROM bank.  This causes a crash when it tries to use a firmware routine.
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 ===== Software That Uses the Floating Bus ===== ===== Software That Uses the Floating Bus =====
  
-The Card does not have any areas of floating bus.  Unused locations on the I/O page tend to return the last key pressed.+The Card does not have any areas of floating bus, and neither the Gemini chip nor the card electronics implement the Apple II video circuitry at all.  Unused locations on the I/O page tend to return the last key pressed.
  
-Most emulators don't get this right, either.+Many emulators don't get this right, either
 + 
 +The end result is that cycle counting programs that use “vapor lock” to synchronize the video will fail
  
 ===== Software that uses Double Low-res Graphics ===== ===== Software that uses Double Low-res Graphics =====