cs5535 National Semiconductor Corporation, cs5535 Datasheet - Page 161

• Manufacturer Part Number: cs5535
• Description: Geode Cs5535 Companion Multi-function South Bridge
• Manufacturer: National Semiconductor Corporation

Revision 0.8
PMC Functional Description
4.17.3 Software Power Management Actions
The hardware comes up from hardware system reset in the
Full On (FO) state. As part of system initialization, the
power management MSRs (see Section 5.18.1 on page
479) are written to establish the Active Hardware Clock
Gating (AHCG) state. The AHCG state is the nominal oper-
ational state.
4.17.3.1 Sleep/Standby Sequence
Entering the states under G1 and G2 requires explicit soft-
ware action. That action starts a hardware chain of events
in which some of the chain is determined by registers that
must be programmed previous to the start of the sequence.
The block diagram of the hardware involved in this
sequence is illustrated in Figure 4-53. Figure 4-54 and Fig-
ure 4-55 graphically show the Sleep/Standby sequence.
The sequence is as follows:
Notes: *At least one per GeodeLink Device.
GeodeLink Device
Activity Counters
External I/O
PM MSR
#Global signal, one per system.
(1 of n)
GLIU
Wakeup from Standby
Power Low Indicator
System Reset if
Figure 4-53. PMC Power Management Elements
Turn Off PCI/IDE Inputs
Turn Off PCI/IDE Outputs
Clock Control
(Continued)
DSMI, SMI, NMI, IRQ
(with Standby power)
161
PML & Reset
1)
2)
3)
4)
The “explicit software action” begins with a write to
PM1_CNT (ACPI I/O Offset 08h) starting the
Sleep/Standby sequence.
The PMC issues a Sleep Request to the CS5535
GLCP and it passes the request as SUSP# to the GX2
GLCP.
The GX2 GLCP issues a suspend request to the pro-
cessor. After the processor has shutdown operation it
provides a suspend acknowledge back to the GX2
GLCP.
The GX2 GLCP processes a sleep sequence similar to
that described in step 5 while issuing a SUSPA# to the
CS5535 GLCP.
Sleep Request
(CIS packet)
SUSP#
Sleep Acknowledge
Internal Wakeup Events
External Wakeup and Thermal
Events including Buttons
SLEEP_X, SLEEP_Y,
SLP_CLK_EN#, WORKING,
and WORK_AUX
Processor
GLCP
SUSPA#
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