Datasheet

Datasheet 75
Land Listing and Signal Descriptions
INIT# Input
INIT# (Initialization), when asserted, resets integer registers inside
the processor without affecting its internal caches or floating-point
registers. The processor then begins execution at the power-on
Reset vector configured during power-on configuration. The
processor continues to handle snoop requests during INIT#
assertion. INIT# is an asynchronous signal and must connect the
appropriate pins/lands of all processor FSB agents.
If INIT# is sampled active on the active to inactive transition of
RESET#, then the processor executes its Built-in Self-Test (BIST).
ITP_CLK[1:0] Input
ITP_CLK[1:0] are copies of BCLK that are used only in processor
systems where no debug port is implemented on the system board.
ITP_CLK[1:0] are used as BCLK[1:0] references for a debug port
implemented on an interposer. If a debug port is implemented in the
system, ITP_CLK[1:0] are no connects in the system. These are not
processor signals.
LINT[1:0] Input
LINT[1:0] (Local APIC Interrupt) must connect the appropriate
pins/lands of all APIC Bus agents. When the APIC is disabled, the
LINT0 signal becomes INTR, a maskable interrupt request signal,
and LINT1 becomes NMI, a nonmaskable interrupt. INTR and NMI
are backward compatible with the signals of those names on the
previous Pentium processor. Both signals are asynchronous.
Both of these signals must be software configured via BIOS
programming of the APIC register space to be used either as NMI/
INTR or LINT[1:0]. Because the APIC is enabled by default after
Reset, operation of these signals as LINT[1:0] is the default
configuration.
LL_ID[1:0] Output
The LL_ID[1:0] signals are used to select the correct loadline slope
for the processor. LL_ID[1:0] = 00 for the Pentium D processor.
LOCK#
Input/
Output
LOCK# indicates to the system that a transaction must occur
atomically. This signal must connect the appropriate pins/lands of
all processor FSB agents. For a locked sequence of transactions,
LOCK# is asserted from the beginning of the first transaction to the
end of the last transaction.
When the priority agent asserts BPRI# to arbitrate for ownership of
the processor FSB, it will wait until it observes LOCK# de-asserted.
This enables symmetric agents to retain ownership of the processor
FSB throughout the bus locked operation and ensure the atomicity
of lock.
MCERR#
Input/
Output
MCERR# (Machine Check Error) is asserted to indicate an
unrecoverable error without a bus protocol violation. It may be
driven by all processor FSB agents.
MCERR# assertion conditions are configurable at a system level.
Assertion options are defined by the following options:
• Enabled or disabled.
• Asserted, if configured, for internal errors along with IERR#.
• Asserted, if configured, by the request initiator of a bus transaction after
it observes an error.
• Asserted by any bus agent when it observes an error in a bus transaction.
For more details regarding machine check architecture, refer to the
IA-32 Software Developer’s Manual, Volume 3: System
Programming Guide.
Table 25. Signal Description (Sheet 1 of 9)
Name Type Description