Full-speed mode

Overview:

Emulation can be run in full-speed (aka unthrottled) mode.

Details:

This can be enabled manually or automatically in a variety of ways:

• Permanently enable by the AppleWin Configuration tab's 'Emulation Speed Control', and setting 'Custom Speed (in MHz)' to 'Fastest'.
• Scroll Lock key: can be configured to toggle normal/full-speed mode, or only enable full-speed when pressed.
  • See Input for configuring how Scroll Lock behaves.
• When 'Disk access speed' is set to 'Enhanced Speed' (the default), then whenever the Disk][ drive motor is on, the emulator will automatically switch to full-speed (and when the motor is switched off, then the emulator will automatically revert to what the 'Emulation Speed Control' has been set to).
  • See Disk for configuring 'Disk access speed'.
• From the built-in debugger, single-stepping via the 'gg' command.

Limitations and things to bear in mind:

• Full speed mode favours speed over video accuracy:
  • The Apple II's video is only updated periodically (once a wall-clock 60Hz frame) instead of each opcode.
• All sound (speaker, Mockingboard, etc) is muted.
• Video-based timing/synchronisation loops won't work correctly.
  • The video-scanner won't advance its h/v position, so the floating bus will always return the same value.
  • Specifically code that does Apple II+ VBlank detection (using the floating bus) will hang, until full-speed mode is disabled. (But Apple //e soft-switch VBlank detection does work.)
• Card detection routines (that rely on floating bus) won't work correctly.
• One of your PC's CPU cores will run at 100%.
  • EG. Simply boot the Apple II (or //e) without a disk in drive-1.