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Land Listing and Signal Descriptions
Table 25.
Signal Description (Sheet 1 of 9)
Name
IGNNE#
IMPSEL
INIT#
ITP_CLK[1:0]
LINT[1:0]
LL_ID[1:0]
LOCK#
Datasheet
Type
IGNNE# (Ignore Numeric Error) is asserted to the processor to
ignore a numeric error and continue to execute noncontrol floating-
point instructions. If IGNNE# is de-asserted, the processor
generates an exception on a noncontrol floating-point instruction if
a previous floating-point instruction caused an error. IGNNE# has
Input
no effect when the NE bit in control register 0 (CR0) is set.
IGNNE# is an asynchronous signal. However, to ensure recognition
of this signal following an Input/Output write instruction, it must be
valid along with the TRDY# assertion of the corresponding Input/
Output Write bus transaction.
IMPSEL input will determine whether the processor uses a 50 Ω or
Input
60 Ω buffer. This pin must be tied to GND on 50Ω platforms and left
as NC on 60Ω platforms.
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#
Input
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] 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
Input
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] (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
Pentium processor. Both signals are asynchronous.
Input
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.
The LL_ID[1:0] signals are used to select the correct loadline slope
Output
for the processor. LL_ID[1:0] = 00 for the Pentium 4 processor.
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.
Input/
Output
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.
Description
69
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