Intel
82801BA ICH2 Datasheet
2-7
Signal Description
2.9
USB Interface
2.10
Power Management Interface
Table 2-9. USB Interface Signals
Name
Type
Description
USBP0P,
USBP0N,
USBP1P,
USBP1N
I/O
Universal Serial Bus Port 1:0 Differential:
These differential pairs are used to
transmit Data/Address/Command signals for ports 0 and 1
(USB Controller 1).
USBP2P,
USBP2N,
USBP3P,
USBP3N
I/O
Universal Serial Bus Port 3:2 Differential:
These differential pairs are used to
transmit Data/Address/Command signals for ports 2 and 3
(USB Controller 2).
OC[3:0]#
I
Overcurrent Indicators:
These signals set corresponding bits in the USB
controllers to indicate that an overcurrent condition has occurred.
Table 2-10. Power Management Interface Signals
Name
Type
Description
THRM#
I
Thermal Alarm:
THRM# is an active low signal generated by external hardware to
start the hardware clock throttling mode. This signal can also generate an SMI# or
an SCI.
SLP_S3#
O
S3 Sleep Control:
Power plane control. This signal is used to shut off power to all
non-critical systems when in S3 (Suspend To RAM), S4 (Suspend to Disk) or S5
(Soft Off) states.
SLP_S5#
O
S5 Sleep Control:
Power plane control. This signal is used to shut power off to all
non-critical systems when in the S4 (Suspend To Disk) or S5 (Soft Off) states.
PWROK
I
Power OK:
When asserted, PWROK is an indication to the ICH2 that core power
and PCICLK have been stable for at least 1 ms. PWROK can be driven
asynchronously. When PWROK is negated, the ICH2 asserts PCIRST#.
PWRBTN#
I
Power Button:
The Power Button will cause SMI# or SCI to indicate a system
request to go to a sleep state. If the system is already in a sleep state, this signal
will cause a wake event. If PWRBTN# is pressed for more than 4 seconds, this will
cause an unconditional transition (power button override) to the S5 state with only
the PWRBTN# available as a wake event. Override will occur even if the system is
in the S1-S4 states. This signal has an internal pull-up resistor.
RI#
I
Ring Indicate:
From the modem interface. This signal can be enabled as a wake
event; this is preserved across power failures.
RSMRST#
I
Resume Well Reset:
Used for resetting the resume power plane logic.
RSM_PWROK
I
Resume Well Power OK:
When asserted, this signal is an indication to the ICH2
that the resume well power (VccSus3_3, VccSus1_8) has been stable for at least
10 ms.
SUS_STAT#
/
LPCPD#
O
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
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.
SUSCLK
O
Suspend Clock:
This signal is an output of the RTC generator circuit and is used
by other chips for the refresh clock.
VRMPWRGD
I
VRM Power Good:
This should be connected to be the processor’s VRM Power
Good.
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