Teledyne LeCroy
PCI Express Mid-Bus Probe for Summit Analyzers
Version 1.1
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3.2 Mid-bus Probe Retention
To prepare a circuit board for PCI Express mid-bus probing, the mid-bus footprint has to be laid out onto the target system
board and a retention module has to be attached to the board. Retention module attachment is simple and quick. There
are four through-hole pins as part of the footprint design, two on each end of the footprint. The two holes of the Teledyne
LeCroy universal retention module fit on each end of the footprint (see installation section 5). The probe aligns to the
retention module with four alignment pins (two on each side), and attaches securely with thumbscrews that fasten into the
retention module, holding the probe pins firmly in connection with the exposed pads of the footprint designed into the
PCB.
The retention module should not be confused with a PCB connector because it is not part of the electrical circuits of either
the target system or the probe. With the use of a retention module, the requirement to have a keep out area on the
backside of the board is eliminated.
Retention modules can be purchased through Teledyne LeCroy:
Half-size or full-size: P/N PE076ACA-X Universal Retention Module
3.3 Probe Connection to Analyzer
The bus signals captured by the mid-bus probe are connected to a mid-bus probe pod for amplification. This reduces the
load imposed by the mid-bus probe on the target system, while allowing a longer cable to attach to the Teledyne LeCroy
PCI Express protocol analyzer. The Teledyne LeCroy PCI Express protocol analyzer can then interpret these signals for
full decoding and protocol analysis.
3.4 Probe Keepout Volume
As with any connection to a PCB, sufficient clearance must be allowed around the point where the probe will connect.
This is defined as the keep-out volume, which must be kept clear of other components mounted on the PCB.
The probe keepout volumes are shown in the diagrams in Section 3.1.