Datasheet

Mobile Intel
®
Pentium
®
III Processor in BGA2 and Micro-PGA2 Packages at 1 GHz,
900 MHz, 850 MHz, 800 MHz, 750 MHz, 700 MHz, Low-voltage 750 MHz, Low-voltage 700 MHz,
Low-voltage 600 MHz, Ultra Low-voltage 600 MHz and Ultra Low-voltage 500 MHz
74 Datasheet 283653-002
PREQ# (I - 1.5V Tolerant)
The PREQ# (Probe Request) signal is used by debug tools to request debug operation of the
processor.
PWRGOOD (I - 2.5V Tolerant)
PWRGOOD (Power Good) is a 2.5-V tolerant input. The processor requires this signal to be a
clean indication that clocks and the power supplies (V
CC
, V
CCT
, etc.) are stable and within their
specifications. Clean implies that the signal will remain low, (capable of sinking leakage current)
and without glitches, from the time that the power supplies are turned on, until they come within
specification. The signal will then transition monotonically to a high (2.5V) state. Figure 26
illustrates the relationship of PWRGOOD to other system signals. PWRGOOD can be driven
inactive at any time, but clocks and power must again be stable before the rising edge of
PWRGOOD. It must also meet the minimum pulse width specified in Table 16 (Section 3.7) and
be followed by a 1 ms RESET# pulse.
Figure 26. PWRGOOD Relationship at Power On
BCLK
PWRGOOD
RESET#
D0026-01
1 msec
V
IH25,min
V
CC
,
V
CCT
,
V
REF
The PWRGOOD signal, which must be supplied to the processor, is used to protect internal
circuits against voltage sequencing issues. The PWRGOOD signal should be driven high
throughout boundary scan operation.
REQ[4:0]# (I/O - GTL+)
The REQ[4:0]# (Request Command) signals must be connected to the appropriate pins/balls on
both agents on the system bus. They are asserted by the current bus owner when it drives A[35:3]#
to define the currently active transaction type.
RESET# (I - GTL+)
Asserting the RESET# signal resets the processor to a known state and invalidates the L1 and L2
caches without writing back Modified (M state) lines. For a power-on type reset, RESET# must
stay active for at least 1 msec after V
CC
and BCLK have reached their proper DC and AC
specifications and after PWRGOOD has been asserted. When observing active RESET#, all bus