Debug Tools Specifications; Logic Analyzer Interface (Lai); Mechanical Considerations; Electrical Considerations - Intel Pentium 4 Design Manual

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Debug Tools Specifications

14.1

Logic Analyzer Interface (LAI)

Intel is working with two logic analyzer vendors to provide logic analyzer interfaces (LAIs) for
use in debugging the Pentium 4 processor in the 478-pin package systems. 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 these systems, the LAI is critical in providing the ability to probe and
capture system bus signals. There are two sets of considerations to keep in mind when designing a
system that can make use of an LAI: mechanical and electrical.
14.1.1

Mechanical Considerations

The LAI is installed between the processor socket and the processor package. The LAI pins plug
into the socket, while the processor pins plug into a socket on the LAI. Cabling that is part of the
LAI egresses the system to allow an electrical connection between the 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 processor heat
sink. If this is the case, the logic analyzer vendor will provide a cooling solution as part of the LAI.
14.1.2

Electrical Considerations

The LAI will also affect the electrical performance of the system bus; therefore, it is critical to
obtain electrical load models from each of the logic analyzers to be able 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.
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Intel Pentium 4 Processor / Intel
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850 Chipset Family Platform Design Guide
Debug Tools Specifications
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