Filter
Top Products
System Introduction 1-29
•
CPU
The CPU clock.
The clock to the CPU can be physically stopped. The chip is static, so the
current state is retained. During a clock stop state, the CPU is stopped and the internal cache
and external bus signals are inoperative. Therefore, any bus master or DMA activity is halted
as well.
CPU thermal alarm.
Thermal alarm is signaled by the assertion of the one control pin [pin4 of
U7(PT3_ATFZNT#) from MMO module], will trigger a lower speed operation through clock
throttling while the CPU temperature is higher than 80
°
C, shut down the system while higher
than 95
°
C. The system returned to normal condition while the CPU temperature is lower to
75
°
C.
•
System
The system can also be put into a low power state. However, this state can only be performed
after the individually power managed components have achieved their low power state. The
state where the system is put into lower power mode is termed static suspend (suspend-to-
memory).
System thermal alarm.
System thermal rating is obtained by the a thermal sensor aside
charger and signaled by the pin-64(SM5_THERM_SYS) of SMC. Full charge to battery is only
available when the system temperature is less than 56
°
C while trickle charge higher than 58
°
C.
System shutdown will be automatically executed while temperature is higher than 85
°
C.
1.6.7.3 Suspend
There are two forms of suspend and resume on the notebook, static suspend(suspend-to-memory)
and zero-volt suspend(suspend-to-disk). Zero-volt suspend is, as the name implies, an OFF
condition. The entire computer state is saved to a disk file and the computer is turned off. In static
suspend, all components are placed into an idle state and the clocks are stopped to the entire
machine, except for the 32 kHz clock for memory refresh.
In either case, all separate components in the system are put into their lowest power state at the
start of either suspend process.
1.
Devices turned off.
The HDD(except for suspend-to-disk since the file goes there), CD-ROM,
floppy are turned off at the start of any suspend.
2.
Devices brought to a low power state.
The audio, serial port transceiver (MAX213), FIR,
keyboard controller, PCMCIA controller chip will be put into a low power state instantly through a
pin asserting or prematurely expiring the device timer.
3.
Devices zero-clocked.
Since the remainder of the devices (video, CPU, IDE controller, ISA bus,
87338’s devices (serial and floppy)) are, by design, static devices, their lowest power states are
achieved by removing the clock to the device.
The very act of going into a suspend-to-memory means that the enable pin to the clock generator
chip is deasserted, removing all but the 32 kHz signal from the board. This excludes, however, the
clocks dedicated to the internal modem. They will remained powered and oscillating.