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mg_notes:iie_card:problem_software [2017/08/28 17:57]
M.G. Floating bus
mg_notes:iie_card:problem_software [2019/10/14 03:59] (current)
M.G. [Software That Uses the Floating Bus]
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 ====== LC //e Card - Problematic Software ====== ====== LC //e Card - Problematic Software ======
  
-Nearly all software that doesn'​t work on the Apple %%//%%e Card for Macintosh LC is likely because of accesses to $C029. ​ This location is the NEWVIDEO register on the Apple IIgs which is used for, among other things, turning on and off super hi-res graphics modes.+Nearly all software that crashes ​on the Apple %%//%%e Card for Macintosh LC is likely because of accesses to $C029. ​ This location is the NEWVIDEO register on the Apple IIgs which is used for, among other things, turning on and off super hi-res graphics modes.
  
 [[http://​www.1000bit.it/​support/​manuali/​apple/​technotes/​misc/​tn.misc.15.html|TN.MISC.15]] cautions against using this location without first identifying the machine. ​ Ironically, the document is mistaken as to the outcome on the IIc Plus, and doesn'​t mention the %%//%%e Card at all. [[http://​www.1000bit.it/​support/​manuali/​apple/​technotes/​misc/​tn.misc.15.html|TN.MISC.15]] cautions against using this location without first identifying the machine. ​ Ironically, the document is mistaken as to the outcome on the IIc Plus, and doesn'​t mention the %%//%%e Card at all.
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 On the %%//%%e Card, accessing $C029 switches out the main firmware in favor of the active alternate firmware bank.  A subsequent attempted use of common firmware routines will not go well. On the %%//%%e Card, accessing $C029 switches out the main firmware in favor of the active alternate firmware bank.  A subsequent attempted use of common firmware routines will not go well.
  
-===== Bitsy Bye =====+Other software may produce unexpected output on the screen depending on how it uses the disk, or if it uses DGR graphics.  
 + 
 +===== 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.
  
-A fixed version of 2.4.1 is available [[projects:​prodos_241_lc|on this page]], and future releases should be fixed.+A fixed version of 2.4.1 is available [[old_stuff:​prodos_241_lc|on this page]], ​[[http://​www.callapple.org/​vintage-apple-computers/​apple-ii/​announcing-prodos-2-4-2-for-all-apple-ii-computers/​|ProDOS 2.4.2]] ​and later correct this.
  
 ===== Apple II Desktop 1.1 ===== ===== Apple II Desktop 1.1 =====
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 Two parts of the program access $C029 without checking to see if the machine is a IIgs or not. Two parts of the program access $C029 without checking to see if the machine is a IIgs or not.
  
 +A fixed version of the software is [[https://​www.a2desktop.com/​about|in development]].
 ===== Software That Leaves the Disk II Motor On ===== ===== Software That Leaves the Disk II Motor On =====
  
-Software that leaves the Disk II motor on will not produce output while the motor is on.  This can be rather unsettling when running programs such as FASTDSK or the Locksmith Fast Copy program.+Software that leaves the Disk II motor on will not produce ​display ​output while the motor is on.  This can be rather unsettling when running programs such as FASTDSK or the Locksmith Fast Copy program.
  
 Games that display messages as they load data from the disk are also likely to misbehave. Games that display messages as they load data from the disk are also likely to misbehave.
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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. 
 + 
 +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 =====
  
-Most emulators don't get this righteither.+The IIe Startup application does not correctly display double low-res colorsgetting every other column wrong
  
 +The color palettes are in the resources of IIe Startup, it may be possible to fix this.