PENTIUM II PROCESSOR AT 233 MHZ, 266 MHZ, 300 MHZ, AND 333 MHZ
E
20
2.8.1.
ASYNCHRONOUS VS.
SYNCHRONOUS FOR SYSTEM BUS
SIGNALS
All GTL+ signals are synchronous to BCLK. All of the
CMOS, Clock, APIC and TAP signals can be applied
asynchronously to BCLK, except when running two
processors in FRC mode. Synchronization logic is
required on all signals going to both processors in
order to run in FRC mode.
Also note the timing requirements for FRC mode
operation. With FRC enabled, PICCLK must be of
BCLK and synchronized with respect to BCLK.
PICCLK must always lag BCLK as specified in
Table 15.
All APIC signals are synchronous to PICCLK. All
TAP signals are synchronous to TCK.
2.9.
Test Access Port (TAP)
Connection
Due to the voltage levels supported by other
components in the Test Access Port (TAP) logic, it is
recommended that the Pentium II processor be first
in the TAP chain and followed by any other
components within the system. A translation buffer
should be used to connect to the rest of the chain
unless one of the other components is capable of
accepting a 2.5 V input. Similar considerations must
be made for TCK, TMS and TRST#. Two copies of
each signal may be required with each driving a
different voltage level.
A Debug Port is described in the Pentium
II
Processor Developer’s Manual(Order Number
243341). The Debug Port will have to be placed at
the start and end of the TAP chain with the TDI of the
first component coming from the Debug Port and the
TDO from the last component going to the Debug
Port. In a 2-way MP system, be cautious when
including an empty Slot 1 connector in the scan
chain. All connectors in the scan chain must have a
processor installed to complete the chain or the
system must support a method to bypass empty
connectors; the Slot 1 terminator substrate connects
TDI to TDO. See the Pentium
II Processor
Developer’s Manual(Order Number 243341) for
more details.
2.10.
Maximum Ratings
Table 5 contains Pentium II processor stress ratings
only. Functional operation at the absolute maximum
and minimum is not implied nor guaranteed. The
processor should not receive a clock while subjected
to these conditions. Functional operating conditions
are given in the AC and DC tables. Extended
exposure to the maximum ratings may affect device
reliability. Furthermore, although the processor
contains protective circuitry to resist damage from
static electric discharge, one should always take
precautions to avoid high static voltages or electric
fields.
2.11.
Processor DC Specifications
The processor DC specifications in this section are
defined at the Pentium II processor edge fingers. See
Appendix A for the processor edge finger signal
definitions.
Most of the signals on the Pentium II processor
System Bus are in the GTL+ signal group. These
signals are specified to be terminated to 1.5 V. The
DC specifications for these signals are listed in
Table 8.
To allow connection with other devices, the Clock,
CMOS, APIC and TAP are designed to interface at
non-GTL+ levels. The DC specifications for these
pins are listed in Table 8.
Table 6 through Table 9 list the DC specifications for
the Pentium II processor. Specifications are valid
only
while
meeting
specifications
temperature, clock frequency and input voltages.
Care should be taken to read all notes associated
with each parameter.
for
case