82801BA Datasheet, PDF (44/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Signal Description
Table 2-10. Power Management Interface Signals
Name
SUS_STAT# /
LPCPD#
C3_STAT# /
GPIO[21]
(ICH2-M only)
SUSCLK
VRMPWRGD
(ICH2)
VRMPWRGD/
VGATE
(ICH2-M)
VGATE /
VRMPWRGD
(ICH2-M only)
AGPBUSY#
(ICH2-M only)
STP_PCI#
(ICH2-M only)
STP_CPU#
(ICH2-M only)
BATLOW#
(ICH2-M only)
CPUPERF#
(ICH2-M only)
SSMUXSEL
(ICH2-M only)
Type
Description
Suspend Status: This signal is asserted by the ICH2 to indicate that the system
will be entering a low power state soon. This can be monitored by devices with
O
memory that need to switch from normal refresh to suspend refresh mode. It can
also be used by other peripherals as an indication that they should isolate their
outputs that may be going to powered-off planes. This signal is called LPCPD# on
the LPC interface.
C3_STAT#: This ICH2-M signal is typically configured as C3_STAT#. It is used for
O indicating to an AGP device that a C3 state transition is beginning or ending. If
C3_STAT# functionality is not required, this signal can be used as a GPO.
O
Suspend Clock: This signal is an output of the RTC generator circuit and is used
by other chips for the refresh clock.
I
VRM Power Good (ICH2 and ICH2-M): VRMPWRGD should be connected to be
the processor’s VRM Power Good.
VRM Power Good Gate (ICH2-M): VGATE is used for Intel^® SpeedStep^TM
technology support. It is an output from the processor’s voltage regulator to
I
indicate that the voltage is stable. This signal can go inactive during a Intel^®
SpeedStep^TM transition. In non-Intel^® SpeedStep^TM technology systems this
signal should be connected to the processor VRM Power Good.
AGP Bus Busy: This signal supports the C3 state. It provides an indication that the
I AGP device is busy. When this signal is asserted, the BM_STS bit will be set. If this
functionality is not needed, this signal may be configured as a GPI.
Stop PCI Clock: This signal is an output to the external clock generator to turn off
O the PCI clock. It is used to support PCI CLKRUN# protocol. If this functionality is
not needed, this signal can be configured as a GPO.
Stop CPU Clock: Output to the external clock generator to turn off the processor
O clock. It is used to support the C3 state. If this functionality is not needed, this
signal can be configured as a GPO.
Battery Low: Input from battery to indicate that there is insufficient power to boot
I
the system. Assertion prevents wake from S1–S5 state. This signal can also be
enabled to cause an SMI# when asserted. In desktop configurations this signal
should be pulled high to VccSUS.
CPU Performance: This signal is used for Intel^® SpeedStep^TM technology
OD
support. It selects which power state to put the processo in. If this functionality is
not needed, this signal can be configured as a GPO. This is an open-drain output
signal and requires an external pull-up to the processor I/O voltage.
SpeedStep Mux Select: This signal is used for Intel^® SpeedStep^TM technology
O support. It selects the voltage level for the processor. If this functionality is not
needed, this signal can be configured as a GPO.
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82801BA ICH2 and 82801BAM ICH2-M Datasheet