Guide

Mobile Intel Pentium 4 Processor–M and Mobile Intel Celeron Processor FSB Design Guidelines

46 Intel

852GM Chipset Platform Design Guide

4.4.1. Logic Analyzer Interface (LAI)

Intel is working with two logic analyzer vendors to provide logic analyzer interfaces (LAIs) for use in

debugging the Mobile Intel Pentium 4 Processor–M based system. Tektronix* and Agilent* should be

contacted to get specific information about their logic analyzer interfaces. The following information is

general in nature. Specific information must be obtained from the logic analyzer vendor.

Due to the complexity of the Mobile Intel Pentium 4 Processor–M based system, the LAI is critical in

providing the ability to probe and capture Front Side Bus signals. There are two sets of considerations to

keep in mind when designing a Mobile Intel Pentium 4 Processor–M that can make use of an LAI:

mechanical and electrical.

4.4.1.1. Mechanical Considerations

The LAI is installed between the processor socket and the Mobile Intel Pentium 4 Processor–M. The

LAI pins plug into the socket, while the Mobile Intel Pentium 4 Processor–M plugs into a socket on the

LAI. Cabling that is part of the LAI egresses the system to allow an electrical connection between the

Mobile Intel Pentium 4 Processor–M and a logic analyzer. The maximum volume occupied by the LAI,

known as the keepout volume, as well as the cable egress restrictions, should be obtained from the logic

analyzer vendor. System designers must make sure that the keepout volume remains unobstructed inside

the system. Note that it is possible that the keepout volume reserved for the LAI may include space

normally occupied by the Mobile Intel Pentium 4 Processor–M heat sink. If this is the case, the logic

analyzer vendor will provide a cooling solution as part of the LAI.

4.4.1.2. Electrical Considerations

The LAI will also affect the electrical performance of the Front Side Bus; therefore, it is critical to

obtain electrical load models from each of the logic analyzers in order to run system level simulations to

prove that their tool will work in the system. Contact the logic analyzer vendor for electrical

specifications and load models for the LAI solution they provide.

4.5. Mobile Intel Pentium 4 Processor–M and Intel 852GM

Chipset FSB Signal Package Lengths

Table 12 lists the preliminary package trace lengths of the Mobile Intel Pentium 4 Processor–M and the

Intel 852GM GMCH for the source synchronous data and address signals. Refer to Section 4.3.1 for

further details. The Mobile Intel Pentium 4 Processor–M and Intel 852GM GMCH package traces are

routed as micro-strip lines with a nominal characteristic impedance of 55 Ω ± 15%.

Table 12. Mobile Intel Pentium 4 Processor-M and Intel 852GM Chipset Package Lengths

Processor lengths GMCH Lengths

Signal Processor

Ball

Length

(inches)

Signal GMCH ball Length

(mils)

Address Group 0

ADSTB[0]# L5 0.210 HADSTB[0]# T26 419

A[3]# K2 0.368 HA[3]# P23 468

A[4]# K4 0.265 HA[4]# T25 353