User's Manual

Intel
®
820 Chipset Design Guide 2-43
Layout/Routing Guidelines
2.8 Hub Interface
The MCH and ICH ball assignments have been optimized to simplify hub interface routing. It is
recommended that the hub interface signals be routed directly from the MCH to the ICH on the top
signal layer (they do not need to be run through vias) (refer to Figure 2-4).
The hub interface is broken into two signal groups: data signals and strobe signals. These groups
are:
•
Data Signals
—HL[10:0]
•
Strobe Signals
—HL_STB
—HL_STB#
Note: HL_STB/HL_STB# is a differential strobe pair.
There are no pull-ups or pull-downs required on the hub interface.
Each signal must be routed such that it meets the guidelines documented for the signal group to
which it belongs.
Figure 2-33. Hub Interface Signal Routing Example
ICH MCH
Clocks
10 K Ω
O
HL_STB
HL_STB#
HL[10:0]
CLK66
GCLK
HL11
1.8V