Datasheet 183
Functional Description
5.14.1.2 Handling an Intruder
The PCH has an input signal, INTRUDER#, that can be attached to a switch that is
activated by the system’s case being open. This input has a two RTC clock debounce. If
INTRUDER# goes active (after the debouncer), this will set the INTRD_DET bit in the
TCO2_STS register. The INTRD_SEL bits in the TCO_CNT register can enable the PCH to
cause an SMI# or interrupt. The BIOS or interrupt handler can then cause a transition
to the S5 state by writing to the SLP_EN bit.
The software can also directly read the status of the INTRUDER# signal (high or low) by
clearing and then reading the INTRD_DET bit. This allows the signal to be used as a GPI
if the intruder function is not required.
If the INTRUDER# signal goes inactive some point after the INTRD_DET bit is written
as a 1, then the INTRD_DET bit will go to a 0 when INTRUDER# input signal goes
inactive. Note that this is slightly different than a classic sticky bit, since most sticky
bits would remain active indefinitely when the signal goes active and would
immediately go inactive when a 1 is written to the bit.
Note: The INTRD_DET bit resides in the PCH’s RTC well, and is set and cleared synchronously
with the RTC clock. Thus, when software attempts to clear INTRD_DET (by writing a 1
to the bit location) there may be as much as two RTC clocks (about 65 µs) delay before
the bit is actually cleared. Also, the INTRUDER# signal should be asserted for a
minimum of 1 ms to ensure that the INTRD_DET bit will be set.
Note: If the INTRUDER# signal is still active when software attempts to clear the INTRD_DET
bit, the bit remains set and the SMI is generated again immediately. The SMI handler
can clear the INTRD_SEL bits to avoid further SMIs. However, if the INTRUDER# signal
goes inactive and then active again, there will not be further SMIs, since the
INTRD_SEL bits would select that no SMI# be generated.
5.14.1.3 Detecting Improper Flash Programming
The PCH can detect the case where the BIOS flash is not programmed. This results in
the first instruction fetched to have a value of FFh. If this occurs, the PCH sets the
BAD_BIOS bit. The BIOS flash may reside in FWH or flash on the SPI bus.
5.14.1.4 Heartbeat and Event Reporting using SMLink/SMBus
Heartbeat and event reporting using SMLink/SMBus is no longer supported. The logic in
PCH can be programmed to generate an interrupt to the Management Engine when an
event occurs. The Management Engine will poll the TCO registers to gather appropriate
bits to send the event message to the Gigabit Ethernet controller, if Management
Engine is programmed to do so.
5.14.2 TCO Modes
5.14.2.1 TCO Legacy/Compatible Mode
In TCO Legacy/Compatible mode, only the host SMBus is utilized. The TCO Slave is
connected to the host SMBus internally by default. In this mode, the Intel Management
Engine SMBus controllers are not used and should be disabled by soft strap.
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