Specifications

Intel
®
810E2 Chipset Platform
R
Design Guide 51
3.6. Hub Interface
The 810E2 chipset’s GMCH ball assignment and ICH2 ball assignment have been optimized to simplify
hub interface routing. It is recommended that the hub interface signals be routed directly from the GMCH
to the ICH2 on the top signal layer. Refer to the following figure.
The hub interface is divided into two signal groups: data signals and strobe signals.
• Data Signals:
 HL[10:0]
• Strobe Signals:
 HL_STB
 HL_STB#
Note: HL_STB/HL_STB# is a differential strobe pair.
No pull-ups or pull-downs are required on the hub interface. HL[11] on the ICH2 should be brought out
to a test point for NAND Tree testing. Each signal should be routed such that it meets the guidelines
documented for its signal group.
Figure 22. Hub Interface Signal Routing Example
ICH2 GMCH
Clocks
HL_STB
HL_STB#
HL[10:0]
CLK66
GCLK
HL11
hub_link_sig_routing
NAND tree
test point
3.6.1. Data Signals
Hub interface data signals should be routed with a trace width of 5 mils and a trace spacing of 20 mils.
These signals can be routed with a trace width of 5 mils and a trace spacing of 15 mils for navigation
around components or mounting holes. To break out of the GMCH and the ICH2, the hub interface data
signals can be routed with a trace width of 5 mils and a trace spacing of 5 mils. The signals should be
separated to a trace width of 5 mils and a trace spacing of 20 mils, within 0.3” of the GMCH/ICH2
components.
The maximum trace length for the hub interface data signals is 7”. These signals should each be matched
within ±0.1” of the HL_STB and HL_STB# signals.