Intel
ยฎ
EP80579 Integrated Processor Product Line May 2010
Order Number: 320068-005US 128
System Memory Interface (DIMM)โIntel
ยฎ
EP80579 Integrated Processor Product Line
9.7.1.3.1 ODT Settings
Table 43 and Table 44 provides the DDR2 Controller and DIMM ODT settings for write
and read operations to/from single-rank (SR) and dual-rank (DR) DIMM modules.
Clearance from other signals 20 mils (min)
Board Routing Guidelines
Total Trace Length (TTL) = (L
PKG
+
L
BREAK
+ L
ROUTE
+ L
D2D
+ L
TERM
)
(TTL of CMD/ADD) + 2.5 in ยฑ5% (See Table 46)
L
PKG
See the Intel
ยฎ
EP80579 Integrated Processor Product Line Datasheet
for package length information.
L
BREAK
Max = 0.8 in
L
ROUTE
Calculate from Total Trace Length
L
D2D
Max = 0.8 in
โข Trace length skews for the control signal for DIMM-to-DIMM
routing should not exceed 10 mils
L
TERM
Max = 500 mils
โข Trace length skews for the control signals to the termination
resistors (L
TERM
) should not exceed 200 mils.
On-Board Termination
Parallel Termination Resistor (Rtt) 60 ฮฉ ยฑ1% Figure 81
Length/Skew Matching Rules
Length Tuning Requirements
โข The control signals need to match in length within
ยฑ 20 mils of each other.
Table 42. DDR2 Control Signal Group Routing Guidelines (Sheet 2 of 2)
Parameter
Routing Guidelines for 2-DIMM Solution with
ODT
Figure
Table 43. Write Operation ODT Table
DIMM
Module
Write
Target
Controller
Configuration
DIMM 0
Configuration
DIMM 1
Configuration
DIMM 0 DIMM 1 Rank0 Rank1 Rank0 Rank1
SR Empty Rank0 ODT Off 75 ฮฉ n/a n/a n/a
DR Empty Rank0 ODT Off ODT Off 75 ฮฉ n/a n/a
DR Empty Rank1 ODT Off 75 ฮฉ ODT Off n/a n/a
SR SR Rank0 ODT Off ODT Off n/a 75 ฮฉ n/a
SR SR Rank1 ODT Off 75 ฮฉ n/a ODT Off n/a