Intel 520J - Pentium 4 2.80GHz 800MHz 1MB Socket 775 CPU Datasheet page 70

Supporting hyper-threading technology
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Land Listing and Signal Descriptions
Table 4-3. Signal Description (Sheet 5 of 8)
Name
IGNNE#
INIT#
ITP_CLK[1:0]
LINT[1:0]
LL_ID[1:0]
LOCK#
MCERR#
MSID[1:0]
70
Type
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.
Input
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 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
Input
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] 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
Input
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] (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 for the
Output
processor. LL_ID[1:0] = 00 for the Pentium 4 processor in the 775-land
package.
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.
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/
• Asserted, if configured, for internal errors along with IERR#.
Output
• 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.
MSID[1:0] are provided to indicate the market segment for the processor and
Output
may be used for future processor compatibility or for keying.
Description
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