
Datasheet
115
Intel
Celeron Processor up to 700 MHz
RESET#
I
Asserting the RESET# signal resets the processor to a known state and invalidates
the L1 cache without writing back any of the contents. RESET# must stay active for
at least one millisecond after V
CCCORE
and CLK have reached their proper
specifications. On observing active RESET#, all system bus agents will deassert
their outputs within two clocks.
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
Pentium
Pro Family Developer’s Manual, Volume 1: Specifications
(Order Number
242690).
The processor may have its outputs tristated via power-on configuration. Otherwise,
if INIT# is sampled active during the active-to-inactive transition of RESET#, the
processor will execute its Built-in Self-Test (BIST). Whether or not BIST is executed,
the processor will begin program execution at the power on Reset vector (default
0_FFFF_FFF0h). RESET# must connect the appropriate pins of all processor
system bus agents.
RS[2:0]#
I
The RS[2:0]# (Response Status) signals are driven by the response agent (the
agent responsible for completion of the current transaction), and must connect the
appropriate pins of all processor system bus agents.
The RTTCTRL input signal provides AGTL+ termination control. The Intel
Celeron FC-PGA processor samples this input to sense the presence of
motherboard AGTL+ termination. See the platform design guide for implementation
details.
The SLEWCTRL input signal provides AGTL+ slew rate control. The Intel
Celeron FC-PGA processor samples this input to determine the slew rate for
AGTL+ signals when it is the driving agent. See the platform design guide for
implementation details.
RTTCTRL
I
SLEWCTRL
I
SLOTOCC#
(S.E.P.P. only)
O
SLOTOCC# is defined to allow a system design to detect the presence of a
terminator card or processor in a SC242 connector. This pin is not a signal; rather, it
is a short to V
SS
. Combined with the VID combination of VID[4:0]= 11111 (see
Section 2.5
), a system can determine if a SC242 connector is occupied, and
whether a processor core is present. The states and values for determining the type
of cartridge in the SC242 connector is shown below.
SC242 Occupation Truth Table
SLP#
I
The SLP# (Sleep) signal, when asserted in Stop-Grant state, causes processors 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 assertions of the SLP#, STPCLK#, and RESET# signals while in
Sleep state. If SLP# is deasserted, the processor exits Sleep state and returns to
Stop-Grant state, restarting its internal clock signals to the bus and APIC processor
core units.
SMI#
I
The SMI# (System Management Interrupt) signal is asserted asynchronously by
system logic. On accepting a System Management Interrupt, processors save 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.
Table 54. Alphabetical Signal Reference (Sheet 5 of 7)
Signal
Type
Description
Signal
Value
Status
SLOTOCC#
VID[4:0]
SLOTOCC#
VID[4:0]
SLOTOCC#
VID[4:0]
0
Anything other than ‘11111’
0
11111
1
Any value
Processor with core in SC242
connector.
Terminator cartridge in SC242
connector (i.e., no core present).
SC242 connector not occupied.