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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.

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.

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

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 on this page, ProDOS 2.4.2 and later correct this.

Apple II Desktop 1.1

Two parts of the program access $C029 without checking to see if the machine is a IIgs or not.

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.

Games that display messages as they load data from the disk are also likely to misbehave.

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.

Most emulators don't get this right, either.