Mobile Intel Pentium 4 Processor - M and Intel 845MP/MZ Chipset Platform Design Guide

Mobile Intel
®
Pentium
®
4 Processor-M and Intel
®
845MP/845MZ Chipset Platform
64 Design Guide
R
5.2.2.1. Control Group Signal Length Matching Requirements
The control signals must be 1.0 inch to 3.0 inches shorter than their associated differential clocks pair.
Note that these requirements may change in a later revision of the design guide based on a post silicon
simulation analysis.
Length matching equation for SO-DIMM0:
X
1
=SCK/SCK#[2:0]
Y
1
=SCS#[1:0] and SCKE[1:0] = L1 of Figure 26 where,
( X
1
– 3.0” ) ≤ Y
1
≤ ( X
1
– 1.0” )
Length matching equation for SO-DIMM1:
X
2
=SCK/SCK#[5:3]
Y
2
=SCS#[3:2] and SCKE[3:2] = L1 of Figure 26 where,
( X
2
– 3.0” ) ≤ Y
2
≤ ( X
2
– 1.0” )
For example if the clock length of SCK/SCK#[2:0](X
1
) is 3.5 inches then the length of all control signal
routing to SO-DIMM0 must be between 0.5 inches to 2.5 inches, if SCK/SCK#[5:3](X
2
) is 4.5 inches
then the length of all control signal route to SO-DIMM1 must be between 1.5 inches to 3.5 inches.
• The MCH-M package lengths don’t need to be taken into account for routing purpose.
Figure 26 depicts the length matching requirements between the control signals and the clock signals.