
176
AMD Geode SC2200 Processor Data Book
Core Logic Module
Revision 5.1
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 6-6describes 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.
VSB and VBAT are not controlled by any control signal. VSB
exists as long as the AC power is plugged in (for desktop
systems) or the main battery is charged (for mobile sys-
tems). VBAT exists as long as the RTC battery is charged.
The case in which VSB 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
generate an SCI or SMI.
Table 6-6. Power Planes Control Signals vs.
Sleep States
Signal
S0
SL1
SL2
SL3
SL4
and
SL5
PWRCNT1
11000
PWRCNT2
11100
ONCTL#
00001
Table 6-7. Power Planes vs. Sleep/Global States
Sleep/
Global State
VCORE, VCCCRT,
VI/O, VPLL,
AVCCCRT
VSB,
VSBL
VBAT
S0, SL1 and
SL2
On
On or Off
SL3, SL4
and SL5
Off
On
On or Off
G3
Off
On
No Power
Off
Illegal
On
Off
On or Off
Table 6-8. Power Management Events
Event
SCI
SMI
Power Button
Yes
Power Button Override
Yes
-
Bus Master Request
Yes
-
Thermal Monitoring
Yes
USB
Yes
RTC
Yes
ACPI Timer
Yes
GPIO
Yes
SDATA_IN2 (AC97)
Yes
IRRX1
Yes
RI2#
Yes
GPWIO
Yes
Internal SMI signal
Yes
-