307013-003 Datasheet, PDF (182/848 Pages) Intel Corporation – Intel I/O Controller Hub 7

Functional Description
Note:
Notes for previous two numbered lists.
1. Normally, the ICH7 does not send heartbeat messages while in the G0 state
(except in the case of a lockup). However, if a hardware event (or heartbeat)
occurs just as the system is transitioning into a G0 state, the hardware continues to
send the message even though the system is in a G0 state (and the status bits may
indicate this).
These messages are sent via the SMBus. The ICH7 abides by the SMBus rules
associated with collision detection. It delays starting a message until the bus is idle,
and detects collisions. If a collision is detected the ICH7 waits until the bus is idle,
and tries again.
2. WARNING: It is important the BIOS clears the SECOND_TO_STS bit, as the alerts
interfere with the LAN device driver from working properly. The alerts reset part of
the LAN controller and would prevent an operating system’s device driver from
sending or receiving some messages.
3. A system that has locked up and can not be restarted with power button press is
assumed to have broken hardware (bad power supply, short circuit on some bus,
etc.), and is beyond ICH7’s recovery mechanisms.
4. A spurious alert could occur in the following sequence:
— The processor has initiated an alert using the SEND_NOW bit
— During the alert, the THRM#, INTRUDER# or GPIO11 changes state
— The system then goes to a non-S0 state.
Once the system transitions to the non-S0 state, it may send a single alert with an
incremental SEQUENCE number.
5. An inaccurate alert message can be generated in the following scenario
— The system successfully boots after a second watchdog Timeout occurs.
— PWROK goes low (typically due to a reset button press) or a power button
override occurs (before the SECOND_TO_STS bit is cleared).
— An alert message indicating that the processor is missing or locked up is
generated with a new sequence number.
Table 5-40 shows the data included in the Alert on LAN messages.
Table 5-40. Heartbeat Message Data (Sheet 1 of 2)
Field
Comment
Cover Tamper Status
Temp Event Status
1 = This bit is set if the intruder detect bit is set (INTRD_DET).
1 = This bit is set if the Intel^® ICH7 THERM# input signal is asserted.
Processor Missing Event
Status
1 = This bit is set if the processor failed to fetch its first instruction.
TCO Timer Event Status 1 = This bit is set when the TCO timer expires.
Software Event Status 1 = This bit is set when software writes a 1 to the SEND_NOW bit.
Unprogrammed
Firmware Hub Event
Status
1 = First BIOS fetch returned a value of FFh, indicating that the
Firmware Hub has not yet been programmed (still erased).
GPIO Status
1 = This bit is set when GPIO11 signal is high.
0 = This bit is cleared when GPIO11 signal is low.
An event message is triggered on an transition of GPIO11.
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Intel ^® ICH7 Family Datasheet