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SC242 Processor Design Guidelines
This chapter provides SC242 processor design guidelines including Layout Guidelines, general
topology, minimizing crosstalk, motherboard layout rules for non-AGTL+ signals, THRMDP and
THRMDN, and motherboard frequency select for SC242 designs. The layout guidelines are
processor-specific and should be used in conjunction with the
Guidelines". See
guidelines.
®
3.1
Intel
The following layout guide supports designs using Intel
SC242 connector and Intel
Initial Timing Analysis
Table 3-1
These timings are for reference only; obtain each processor's specifications from its
respective Electrical, Mechanical, and Thermal Specification and appropriate Intel
chipset component specification.
®
Table 3-1. Intel
Pentium
Calculations
Clock to Output maximum (T
Clock to Output minimum (T
Setup time (T
Hold time (T
NOTES:
1. All times in nanoseconds.
2. Numbers in table are for reference only. These timing parameters are subject to change. Please check the
appropriate component documentation for valid timing parameter values.
3. T
SU_MIN
Table 3-2
minimum flight time calculation for a 100 MHz, uni-processor system using Intel
processor/Intel
jitter were used. Clock skew and clock jitter values are dependent on the clock components
and distribution method chosen for a particular design and must be budgeted into the initial
timing equations as appropriate for each design.
®
Intel
810A3 Chipset Design Guide
Chapter 5, "Advanced System Bus Design"
®
Pentium
III Processors Layout Guidelines
810A3 chipset at system bus speeds of 100 MHz.
lists the AGTL+ component timings of the processors and GMCH defined at the pins.
®
III Processor and GMCH AGTL+ Parameters for Example
1
IC Parameters
)
CO_MAX
)
CO_MIN
)
SU_MIN
)
HOLD
= 2.72 ns assumes the GMCH sees a minimum edge rate equal to 0.3 V/ns.
gives an example AGTL+ initial maximum flight time and
®
810A3 Chipset system bus. Note that assumed values for clock skew and clock
SC242 Processor Design Guidelines
Chapter 4, "Layout and Routing
for more details on AGTL+ layout
®
Pentium
®
Intel
Pentium III processor
core at 100 MHz System Bus
2.70
-0.10
1.20
0.80
III processors utilizing the
810A3
GMCH
Notes
3.63
2
0.50
2
2.27
2,3
0.28
Table 3-3
is an example
Pentium
3
III
3-1
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