Intel 855GME Design Manual page 149

®
Intel 855GME Chipset and Intel
Length range formula for DIMM1:
X = SCK[5:3]/SCK[5:3]# total reference length, including package length. Refer to
1
for more information.
Y = SMAB[5,4,2,1] total length = GMCH Package length + L1, as shown in
1
– 1.5") ≤ Y
(X
1
No length matching is required from DIMM1 to the termination resistor.
length matching requirements between the CPC signals and clock. A nominal CPC package length
of 500 mils may be used to estimate baseline Mbyte lengths.
Figure 74. CPC Signals to Clock Length Matching Diagram
GMCH Package
855GME
GMCH
Note: All lengths are measured from GMCH
die pad to DIMM connector pad.
GMCH Package
855GME
GMCH
Die
Note: All lengths are measured from GMCH
die pad to DIMM connector pad.
System Memory Design Guidelines (DDR-SDRAM)
≤ (X
- 0.5")
1 1
SMA[5,4,2,1]
SCK[2:0]
Die
SCK#[2:0]
SMAB[5,4,2,1]
SCK[5:3]
SCK#[5:3]
January 2007
®
6300ESB ICH Embedded Platform Design Guide
DIMM0
CPC Length = Y0
(X0 – 1.5") <= Y0 <= (X0 - 0.5")
Clock Reference Length = X0
DIMM0
DIMM1
Section 5.4.1
Figure 73, where:
Figure 74 depicts the
CPC Length = Y1
(X1–1.5") <= Y1 <= (X1-0.5")
Clock Ref Length = X1
149