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Intel® Server Board SE7505VB2
SE7505VB2 ACPI Implementation
The power button input (SW2#) provides PWRBTN_IN signal to the sIO. The power button input
behaves differently depending on whether or not the operating system supports ACPI.
Power Button Off to On:
The sIO may be configured to generate wakeup events for several
different system events: Wake on LAN*, PCI Power Management
Interrupt, and Real Time Clock Alarm are examples of these
events. Since the processors are not executing, the BIOS does not
participate in this sequence. The sIO provides ONSTL# signal to
the power supply. The ICH4 and receive power good and reset and
then transition to an ON state.
Power Button On to Off
(Legacy):
The ICH4 is configured to generate an SMI due to a power button
event. The BIOS services this SMI and sets the state of the
machine in the ICH4 and sIO to the OFF state.
Power Button On to Off
(ACPI):
If an ACPI operating system is loaded, the power button switch
generates a request (via SCI) to the OS to shutdown the system.
The OS retains control of the system and determines what sleep
state (if any) the system transitions to.
Reset Button:
The reset button will generate a hard reset to the system.
NMI Button:
The NMI button will force an NMI to the processors.
7.1.2
Wake up Sources (ACPI and Legacy)
The baseboard is capable of wake up from several sources under a non-ACPI configuration,
such as when the operating system does not support ACPI. The wake up sources are defined in
the following table.
Table 19. Supported Wake Events
Wake Event
Supported via ACPI
(by sleep state)
Supported Via Legacy Wake
Power Button
Always wakes system
Always wakes system
Ring indicate from serial1
S1, S4, S5
S5
Ring indicate from serial2
S1, S4, S5
S5
PME from PCI 32/33
S1, S4, S5
S5
PME from PCI secondary 64/100
S1, S4, S5
S5
PME from primary PCI 64/66
S1, S4, S5
S5
RTC Alarm
S1, S4
No
Mouse S1
No
Keyboard S1
No
USB S1
No
Under ACPI, the operating system programs the ICH4 and sIO to wake up on the desired event,
but in legacy mode, the BIOS enables/disables wake up sources based on an option in BIOS
Setup. The operating system or a driver must clear any pending wake up status bits in the
associated hardware (such as the Wake on LAN status bit in the LAN application specific
integrated circuit (ASIC), or PCI Power Management Event (PME) status bit in a PCI device.
The legacy wake up feature is disabled by default.
Revision 1.2
Intel part number C32194-002
49