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168 AMD Geode™ SC2200 Processor Data Book
Core Logic Module
32580B
6.2.9.3 Power Planes Control
The SC2200 supports up to three power planes. Three sig-
nals are used to control these power planes. Table 6-6
describes the signals and when each is asserted.
These signals allow control of the power of system devices
and the SC2200 itself. Table 6-7 describes the SC2200
power planes with respect to the different Sleep and Global
states.
The SC2200 power planes are controlled externally by the
three signals (i.e., the system designer should make sure
the system design is such that Table 6-7 is met) for all sup-
ported Sleep states.
V
SB
and V
BAT
are not controlled by any control signal. V
SB
exists as long as the AC power is plugged in (for desktop
systems) or the main battery is charged (for mobile sys-
tems). V
BAT
exists as long as the RTC battery is charged.
The case in which V
SB
does not exist is called Mechanical
Off (G3).
6.2.9.4 Power Management Events
The SC2200 supports power management events that can
manage:
• Transition of the system from a Sleep state to a Work
state. This is done by the hardware. These events are
defined as wakeup events.
• Enabled wakeup events to set the WAK_STS bit
(F1BAR1+I/O Offset 08h[15]) to 1, when transitioning
the system back to the working state.
• Generation of an interrupt. This invokes the relevant
software driver. The interrupt can either be an SMI or
SCI (selected by the SCI_EN bit, F1BAR1+I/O Offset
0Ch[0]). These events are defined as interrupt events.
Table 6-8 lists the power management events that can gen-
erate an SCI or SMI.
Table 6-6. Power Planes Control Signals vs.
Sleep States
Signal S0 SL1 SL2 SL3
SL4
and
SL5
PWRCNT111000
PWRCNT211100
ONCTL# 00001
Table 6-7. Power Planes vs. Sleep/Global States
Sleep/
Global State
V
CORE
, V
CCCRT
,
V
I/O,
V
PLL
,
AV
CCCRT
V
SB
,
V
SBL
V
BAT
S0, SL1 and
SL2
On On On or Off
SL3, SL4
and SL5
Off On On or Off
G3 Off Off On
No Power Off Off Off
Illegal On Off On or Off
Table 6-8. Power Management Events
Event SCI SMI
Power Button Yes Yes
Power Button Override Yes -
Bus Master Request Yes -
Thermal Monitoring Yes Yes
USB Yes Yes
RTC Yes Yes
ACPI Timer Yes Yes
GPIO Yes Yes
SDATA_IN2 (AC97) Yes Yes
IRRX1 Yes Yes
RI2# Yes Yes
GPWIO Yes Yes
Internal SMI signal Yes -