82801BA Datasheet, PDF (46/498 Pages) Intel Corporation – Intel 82801BA I/O Controller Hub 2 (ICH2) and Intel 82801BAM I/O Controller Hub 2 Mobile

Signal Description
Table 2-11. Processor Interface Signals (Continued)
Name
RCIN#
A20GATE
CPUPWRGD
Type
Description
Keyboard Controller Reset Processor: The keyboard controller can generate
INIT# to the processor. This saves the external OR gate with the ICH2’s other
sources of INIT#. When the ICH2 detects the assertion of this signal, INIT# is
generated for 16 PCI clocks..
I ^Note
82801BA ICH2: The 82801BA ignores RCIN# assertion during transitions to the
S3, S4 and S5 states.
82801BAM ICH2-M: The 82801BAM ignores RCIN# assertion during transitions
to the S1, S3, S4 and S5 states.
A20 Gate: This signal is from the keyboard controller. It acts as an alternative
I method to force the A20M# signal active. A20GATE saves the external OR gate
needed with various other PCIsets.
Processor Power Good (82801BA ICH2): This signal should be connected to
the processor’s PWRGOOD input. This is an open-drain output signal (external
pull-up resistor required) that represents a logical AND of the ICH2’s PWROK and
VRMPWRGD signals.
OD ^{CPU Power Good (82801BAM ICH2-M): This signal should be connected to the}
processor’s PWRGOOD input. For Intel^® SpeedStep™ technology support, this
signal is kept high during a Intel^® SpeedStep™ technology state transition to
prevent loss of processor context. This is an open-drain output signal (external
pull-up resistor required) that represents a logical AND of the ICH2-M’s PWROK
and VGATE / VRMPWRGD signals.
2.12 SMBus Interface
Table 2-12. SM Bus Interface Signals
Name
Type
Description
SMBDATA
SMBCLK
SMBALERT#/
GPIO[11]
I/OD
I/OD
I
SMBus Data: External pull-up is required.
SMBus Clock: External pull-up is required.
SMBus Alert: This signal is used to wake the system or generate an SMI#. If not
used for SMBALERT#, it can be used as a GPI.
2.13 System Management Interface
Table 2-13. System Management Interface Signals
Name
Type
Description
INTRUDER#
SMLINK[1:0]
I
I/OD
Intruder Detect: This signal can be set to disable system if box detected open.
This signal’s status is readable, so it can be used like a GPI if the Intruder
Detection is not needed.
System Management Link: These signals are an SMBus link to an optional
external system management ASIC or LAN controller. External pull-ups are
required.
Note that SMLINK[0] corresponds to an SMBus Clock signal and SMLINK[1]
corresponds to an SMBus Data signal.
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82801BA ICH2 and 82801BAM ICH2-M Datasheet