Pin Listing and Signal Descriptions
Table 4-3. Signal Description (Sheet 5 of 8)
Name
Type
Description
IGNNE# (Ignore Numeric Error) is asserted to force 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 no effect when the NE bit in control register 0 (CR0) is set.
IGNNE#
Input
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.
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 of all processor FSB agents.
INIT#
Input
Input
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 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.
ITP_CLK[1:0]
LINT[1:0] (Local APIC Interrupt) must connect the appropriate pins 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.
LINT[1:0]
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 pins as LINT[1:0] is
the default configuration.
LOCK# indicates to the system that a transaction must occur atomically. This
signal must connect the appropriate pins 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
LOCK#
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# (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.
Input/
Output
MCERR#
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.
58
Datasheet
INTEL [ INTEL ]
