Datasheet

Datasheet 57
Package Mechanical Specifications and Pin Information
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. PWRGOOD can be driven inactive at
any time, but clocks and power must again be stable before a
subsequent rising edge of PWRGOOD.
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 both FSB agents. They are asserted by the current bus owner to
define the currently active transaction type. These signals are source
synchronous to ADSTB[0]#.
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
two milliseconds after V
CC
and BCLK have reached their proper
specifications. On observing active RESET#, both FSB agents will de-
assert their outputs within two clocks. All processor straps must be
valid within the specified setup time before RESET# is de-asserted.
There is a 55-Ω (nominal) on die pull-up resistor on this signal.
RS[2:0]# Input
RS[2:0]# (Response Status) are driven by the response agent (the
agent responsible for completion of the current transaction), and
must connect the appropriate pins of both FSB agents.
RSVD
Reserved
/No
Connect
These pins are RESERVED and must be left unconnected on the
board. However, it is recommended that routing channels to these
pins on the board be kept open for possible future use.
SLP# Input
SLP# (Sleep), when asserted in Stop-Grant state, causes the
processor to enter the Sleep state. During Sleep state, the processor
stops providing internal clock signals to all units, leaving only the
Phase-Locked Loop (PLL) still operating. Processors in this state will
not recognize snoops or interrupts. The processor will recognize only
assertion of the RESET# signal, de-assertion of SLP#, and removal of
the BCLK input while in Sleep state. If SLP# is de-asserted, the
processor exits Sleep state and returns to Stop-Grant state,
restarting its internal clock signals to the bus and processor core
units. If DPSLP# is asserted while in the Sleep state, the processor
will exit the Sleep state and transition to the Deep Sleep state.
SMI# Input
SMI# (System Management Interrupt) is asserted asynchronously by
system logic. On accepting a System Management Interrupt, the
processor saves the current state and enter System Management
Mode (SMM). An SMI Acknowledge transaction is issued, and the
processor begins program execution from the SMM handler.
If SMI# is asserted during the de-assertion of RESET# the processor
will tristate its outputs.
Table 19. Signal Description (Sheet 6 of 8)
Name Type Description