Datasheet

71
Signal Definitions
IERR# O IERR# (Internal Error) is asserted by a processor as the result of an
internal error. Assertion of IERR# is usually accompanied by a
SHUTDOWN transaction on the processor FSB. This transaction may
optionally be converted to an external error signal (e.g., NMI) by
system core logic. The processor will keep IERR# asserted until the
assertion of RESET#.
This signal does not have on-die termination.
2
IGNNE# I 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 deasserted, 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# is an asynchronous signal. However, to ensure recognition of
this signal following an I/O write instruction, it must be valid along
with the TRDY# assertion of the corresponding I/O write bus
transaction.
2
INIT# I INIT# (Initialization), when asserted, resets integer registers inside
all processors without affecting their internal caches or floating-point
registers. Each 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.
2
LINT[1:0] I LINT[1:0] (Local APIC Interrupt) must connect the appropriate pins
of all FSB agents. When the APIC functionality is disabled, the
LINT0/INTR signal becomes INTR, a maskable interrupt request
signal, and LINT1/NMI 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.
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.
2
LL_ID[1:0] O The LL_ID[1:0] signals are used to select the correct loadline slope
for the processor. These signals are not connected to the processor
die.
LOCK# I/O 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.
When the priority agent asserts BPRI# to arbitrate for ownership of
the processor FSB, it will wait until it observes LOCK# deasserted.
This enables symmetric agents to retain ownership of the processor
FSB throughout the bus locked operation and ensure the atomicity of
lock.
3
MCERR# I/O 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
Intel
®
64 and IA-32 Architectures Software Developer’s Manual,
Volume 3.
Table 5-1. Signal Definitions (Sheet 5 of 8)
Name Type Description Notes