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Land Listing and Signal Descriptions
Table 25.
Signal Description (Sheet 1 of 9)
Name
RESET#
RS[2:0]#
RSP#
SKTOCC#
SMI#
STPCLK#
TCK
TDI
TDO
Datasheet
Type
Asserting the RESET# signal resets the processor to a known state
and invalidates its internal caches without writing back any of their
contents. For a power-on Reset, RESET# must stay active for at
least one millisecond after V
specifications. On observing active RESET#, all FSB agents will de-
assert their outputs within two clocks. RESET# must not be kept
Input
asserted for more than 10 ms while PWRGOOD is asserted.
A number of bus signals are sampled at the active-to-inactive
transition of RESET# for power-on configuration. These
configuration options are described in the
This signal does not have on-die termination and must be
terminated on the system board.
RS[2:0]# (Response Status) are driven by the response agent (the
agent responsible for completion of the current transaction), and
Input
must connect the appropriate pins/lands of all processor FSB
agents.
RSP# (Response Parity) is driven by the response agent (the agent
responsible for completion of the current transaction) during
assertion of RS[2:0]#, the signals for which RSP# provides parity
protection. It must connect to the appropriate pins/lands of all
processor FSB agents.
Input
A correct parity signal is high if an even number of covered signals
are low and low if an odd number of covered signals are low. While
RS[2:0]# = 000, RSP# is also high, since this indicates it is not
being driven by any agent ensuring correct parity.
SKTOCC# (Socket Occupied) will be pulled to ground by the
Output
processor. System board designers may use this signal to
determine if the processor is present.
SMI# (System Management Interrupt) is asserted asynchronously
by system logic. On accepting a System Management Interrupt, the
processor saves the current state and enter System Management
Mode (SMM). An SMI Acknowledge transaction is issued, and the
Input
processor begins program execution from the SMM handler.
If SMI# is asserted during the de-assertion of RESET#, the
processor will tri-state its outputs.
STPCLK# (Stop Clock), when asserted, causes the processor to
enter a low power Stop-Grant state. The processor issues a Stop-
Grant Acknowledge transaction, and stops providing internal clock
signals to all processor core units except the FSB and APIC units.
Input
The processor continues to snoop bus transactions and service
interrupts while in Stop-Grant state. When STPCLK# is de-
asserted, the processor restarts its internal clock to all units and
resumes execution. The assertion of STPCLK# has no effect on the
bus clock; STPCLK# is an asynchronous input.
TCK (Test Clock) provides the clock input for the processor Test Bus
Input
(also known as the Test Access Port).
TDI (Test Data In) transfers serial test data into the processor. TDI
Input
provides the serial input needed for JTAG specification support.
TDO (Test Data Out) transfers serial test data out of the processor.
Output
TDO provides the serial output needed for JTAG specification
support.
Description
and BCLK have reached their proper
CC
Section
6.1.
71
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