The Macintosh Portable has a number of power-saving features that give it
6 to 12 hours of battery life. The Macintosh Portable contains two
batteries: a main battery that provides power while the computer is in
use, and a backup 9-volt transistor battery that sustains the computer's
memory while the main battery is disconnected (as when a fresh main
battery is being installed).
Note: The main battery is required for operation of the Macintosh
Portable. The hard drive will not spin up without the internal battery.
The power-saving features are controlled by the power-manager processor.
The power-manager processor is a separate "computer" inside the unit that
controls the power functions of the unit.
The Macintosh Portable is the only member of the Macintosh family that is
designed to be powered by a battery. In normal operation, the Macintosh
Portable never switches off. Rather, it goes into a low-power
consumption\\ state, the sleep state, when it is not in use. Ideally, the
Macintosh portable is switched on only when the battery is first installed
or after the battery has been removed to install an expansion card in the
machine.
Sleep
-----
System sleep helps the Macintosh Portable operate longer between charges.
When in sleep state, the Macintosh Portable maintains full power to system
RAM, video RAM, and the power-manager processor. The power-manager
processor stops the clocks to the SCC, the SWIM, and the ASC. Stopping
the clocks to these devices, reduces their power consumption to almost
zero without requiring that they be reset. The power-manager processor
switches off power to the serial drivers, ROM, flat panel display, the
ASC, the Sony sound chips, the SCSI, and to a variety of pull-up resistors
and other components. The power-manager processor also sends a signal to
the internal modem that causes the modem to shut itself down, if not in
use.
The system can enter sleep in the following ways:
- The user selects sleep from the Special menu in the Finder.
- The user selects sleep from the Battery DA.
- The system enters sleep after a period of inactivity (the interval is
user selectable).
- The system enters sleep, because battery power is at the
software-shutdown level.
- This is the first time power is being applied.
- The power-manager processor is reset.
The system will not enter sleep, if the internal modem is executing an AT
command or if the modem is off-hook, except at hardware shutdown.
Macintosh Portable will come out of sleep for any of the following
reasons:
- A key is pressed on the keyboard (except Caps Lock).
- The wake-up timer matches the real-time clock.
- The internal modem is installed, and a ring detect comes in, while the
modem is set to watch for ring detect.
Note: If the unit is in software shutdown, the Macintosh Portable does not
come out of shutdown until the power adapter is plugged in or until the
battery is replaced.
When power is first applied to the Macintosh Portable, the power-manager
processor immediately puts the system into the sleep state. When a key is
pressed, the power-manager processor initiates a system reset and the
Macintosh Portable goes through the same sequence of start-up events as
the Macintosh SE.
Macintosh Portable presents four dialogs to the user when the battery is
running low. The first three warn the user about the power condition, and
the last lets the user know the system is going to sleep mode.
Sleep vs Shut Down
------------------
The Shut Down menu item doesn't care about memory contents and quits
applications before shut down. Sleep saves memory contents. Shut Down
should be used for the following:
- To have the unit wake up and reboot
- To add an external peripheral
- To make sure all applications have been quit
- Hard Drive Sleep. If the Macintosh Portable has a hard drive, the
control panel displays an option to put the hard drive to sleep. This
causes the hard drive to stop spinning. Hard drive sleep automatically
occurs when the Macintosh Portable goes into system sleep.
Any hard disk activity causes the Macintosh Portable to come back out of
hard drive sleep. It takes one or two seconds for the hard drive to get
up to speed, sllowing access to the drive.
Rest
----
The power-manager processor monitors the amount of time the Macintosh
Portable has been inactive. After a period of 15 seconds without any
activity, the unit goes into Rest mode. It causes the CPU to insert 64
wait states into RAM and ROM accesses which lowers the effective clock
rate to approximately 1 MHz. Interrupts continue to be processed at the
same rate. As soon as the trackball or mouse moves, or any peripheral
device is activated, the computer comes up to full speed instantly.
The following items are checked and stop the unit from entering rest mode:
- Mouse movement
- I/O activity, (keyboard, trackball, modem, etc..)
- Cursor change
- Serial port access
This feature can be turned off, when running Video Works or some other
program that avoids detection by the rest routine. The user can disable
rest mode by doing the following:
1) Enter the Control Panel DA and select the Portable icon.
2) Hold Down the Option key and click the words "Minutes Until Automatic
Sleep."
3) Click on Don't Rest in the dialog box that comes up, and select OK
Low Power Warnings
------------------
When the battery starts to run low, a series of messages appears, warning
the user that it is time to recharge. A flashing battery replaces the
Apple Icon in the menu bar. When these messages start to appear, save any
open documents and plug the Macintosh Portable into the power adapter as
soon as possible. (Saving work is a good thing to do every once and a
while, anyway.) The computer can be active, while it is recharging the
battery.
After the fourth warning, the computer automatically goes into system
sleep, while there is still enough power to hold the contents of memory
for five days.
Note: As long the battery is recharged within five days, the contents of
memory remain intact, and the computer will pick up where it left off
before the battery ran low. The only consequence of not recharging within
five days is that the contents of memory are lost.
When not using the computer for more than one month, save any files and
select Shut Down from the Special menu. After shut down, remove the
battery to make sure the battery does not become completely discharged.