System BIOS
SE7500CW2 Server Board Technical Product Specification
40
Revision 1.40
Ring indicate from COM-
A
Wakeup from S4/S5 if the system in the S4/S5 state
Yes
Ring indicate from COM-
B
Wake up from S4/S5 if system in the S4/S5 state If COM-B is used
for emergency management port, COM-B wakeup is disabled.
Yes
PME (Power
Management Event) from
PCI cards
May support wake from S4/S5 if PCI card supports the PME
generation function.
Yes
RTC Alarm
Always wakes the system up from S4.
Yes
6.3.2.1
Front Panel Switches
The BIOS supports up to three front panel buttons: the power button, the reset button, and the
NMI button. The NMI button is not accessible on all front panel designs.
The power switch behaves differently depending on whether the operating system supports
ACPI. If the operating system supports ACPI the power button can be configured as a sleep
button via OS power management option. The OS causes the system to transition to the
appropriate system state depending on the user settings.
6.3.2.1.1
Power Switch Off to On
The chipset may be configured to generate wake up events for several system events: Wake-
on-LAN, PCI Power Management Interrupt, and the Real-Time Clock Alarm are examples of
these events. If the operating system is ACPI-aware, it programs the wake sources before
shutdown. In non-ACPI mode, the BIOS performs the configuration. A transition from power
switch results in the SIO W83627 signal the ICH3 starting the power-up sequence. Since the
processors are not executing, the BIOS does not participate in this sequence. The hardware
receives power good and reset signal then transition to an ON state.
6.3.2.1.2
On to Off (Legacy)
The SIO 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 chipset to the OFF state, then de-asserts the PS.
6.3.2.1.3
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 OS policy determines the
sleep state, if any, into which the system transitions.
6.3.2.1.4
On to Sleep (ACPI)
If an ACPI operating system is loaded and the power button is configured as a sleep button, the
sleep button switch generates a request via SCI to the OS to place the system into sleep mode.
The OS retains control of the system and OS policy determines the sleep state, if any, into
which the system transitions.
6.3.2.1.5
Sleep to On (ACPI)
If an ACPI operating system is loaded and the power button is configured as a sleep button, the
sleep button switch generates a wake event to the ACPI chipset and a request via SCI to the OS
