The Idle State
When the Macintosh Portable computer is inactive for 15 seconds, the
Power Manager firmware causes the CPU to insert 64 wait states into each RAM or ROM access, effectively changing the clock speed from 16 MHz to 1
MHz. This condition is referred to as the idle state.
Note: The inactivity timeout interval, clock speed, and hardware
implementation of the idle state are subject to change in future por table
Macintosh computers.
For the purposes of the idle state, inactivity is defined as the absence of any of
the following:
• a call to the Operating System Event Manager's PostEvent function • any events in the event queue
• any access of the Apple Sound Chip (ASC)
• completion of an Apple Desktop Bus (ADB) transaction cursor
• the cursor displayed as the watch cursor
Whenever the Power Manager detects one of these forms of activity, it resets a timer called the activity timer to 15 seconds and, if the Macintosh
Portable is in the idle state, returns the computer to the operating state.
Neither the user nor your program can change the activity timer to use a
period other than 15 seconds. However, the user can disable the activity timer
through the Portable control panel, and your application can reset, disable,
function to determine whether the Macintosh Portable is currently in the idle