Mobile Intel Pentium 4 Processor with 533 MHz Front Side Bus

62 Mobile Intel
®
Pentium
®
4 Processor with 533 MHz System Bus Datasheet
Pin Listing and Signal Definitions
LOCK#
Input/
Output
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.
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, please refer to the IA-32
Software Developer’s Manual, Volume 3: System Programming Guide.
PROCHOT#
Input/
Output
As an output, PROCHOT# (Processor Hot) will go active when the processor
temperature monitoring sensor detects that the processor has reached its
maximum safe operating temperature. This indicates that the processor Thermal
Control Circuit has been activated, if enabled. As an input, assertion of PROCHOT#
by the system will activate the TCC, if enabled. The TCC will remain active until the
system deasserts PROCHOT#. See Section 6 for more details.
PWRGOOD Input
PWRGOOD (Power Good) is a processor input. The processor requires this signal
to be a clean indication that the clocks and power supplies are stable and within
their specifications. ‘Clean’ implies that the signal will remain low (capable of
sinking leakage current), without glitches, from the time that the power supplies are
turned on until they come within specification. The signal must then transition
monotonically to a high state. Figure 14 illustrates the relationship of PWRGOOD to
the RESET# signal. PWRGOOD can be driven inactive at any time, but clocks and
power must again be stable before a subsequent rising edge of PWRGOOD. It
must also meet the minimum pulse width specification in Table 22, and be followed
by a 1 to 10 ms RESET# pulse.
The PWRGOOD signal must be supplied to the processor; it is used to protect
internal circuits against voltage sequencing issues. It should be driven high
throughout boundary scan operation.
REQ[4:0]#
Input/
Output
REQ[4:0]# (Request Command) must connect the appropriate pins of all processor
FSB agents. They are asserted by the current bus owner to define the currently
active transaction type. These signals are source synchronous to ADSTB0#. Refer
to the AP[1:0]# signal description for details on parity checking of these signals.
RESET# Input
Asserting the RESET# signal resets the processor to a known state and invalidates
its internal caches without writing back any of their contents. For a power-on Reset,
RESET# must stay active for at least one millisecond after V
CC and BCLK have
reached their proper specifications. On observing active RESET#, all FSB agents
will deassert their outputs within two clocks. RESET# must not be kept asserted for
more than 10 ms while PWRGOOD is asserted.
A number of bus signals are sampled at the active-to-inactive transition of RESET#
for power-on configuration. These configuration options are described in the
Section 6.1.
This signal does not have on-die termination and must be terminated on the
system board.
Table 23. Signal Description (Sheet 6 of 8)
Name Type Description