Guide

Hub Interface
R
146 Intel
®
852GM Chipset Platform Design Guide
9.2. Hub Interface Data HL[10:0] and Strobe Signals
The Hub interface HL[10:0] data signals should be routed on the same layer as Hub interface strobe
signals.
9.2.1. HL[10:0] and Strobe Signals Internal Layer Routing
Traces should be routed 4 mils wide with 8 mils trace spacing (4 on 8) and 20 mils spacing from other
signals. In order to break out of the GMCH and ICH4-M packages, the HL[10:0] signals can be routed 4
on 7. The signal must be separated to 4 on 8 within 300 mils from the package.
The maximum HL[10:0] signal trace length is 6 inches. The HL[10:0] signals must be matched within ±
100 mils of the HLSTB differential pair. There is no explicit matching requirement between the
individual HL[10:0] signals.
The hub interface strobe signals HLSTB and HLSTB# should be routed as a differential pair, 4 mils
wide with 8 mils trace spacing (4 on 8). The maximum length for strobe signals is 6 inches. Each strobe
signal must be the same length and each HL[10:0] signal must be matched to within ± 100 mils of the
strobe signals. All length matching should be done from the Intel 852GM die to the ICH4-M die. Refer
to the package length Table 59 and Table 60.
Table 58. Hub Interface Signals Internal Layer Routing Summary
Signal Max
length
(inch)
Width
(mils)
Space
(mils)
Mismatch
length
(mils)
Relative
To
Space with
other
signals
(mils)
Notes
HL[10:0] 6” 4 8 ± 100 Differential
HSTB pair
20
HLSTB
HLSTB#
6” 4 8 ± 100 Data lines 20 HLSTB and HLSTB#
must be ± 10 mils of
each other.