IFTE verify probe capability

Abstract

The Integrated Family of Test Equipment (IFTE) has acquired a verify probe capability for the Base Shop Test Facility/Commercial Equivalent Equipment (BSTF/CEE) similar to the probe capability of the General-purpose Electronic Test Station-1000B (GETS-1000B). Verify probe is a system software routine with which the operator can confirm suspected fault locations. Verify probe is used with Test Program Sets (TPS) developed with Logic Automatic Stimulus and Response (LASAR), a digital automatic test program generator tool. The verify probe capability will enhance the fault detection and fault isolation for IFTE TPSs. The Abbreviated Test Language for All Systems (ATLAS) module reads data files generated by LASAR and then executes the entire LASAR-generated test. If the test should fail, the ATLAS module performs a look-up in the LASAR-generated fault dictionary, displaying the simulated fault which best matches how the Unit Under Test (UUT) has actually failed. The fault dictionary procedure is a good approximation and is completely automatic, requiring no operator intervention. Since it is unlikely that a failure will always match one of the simulated failures exactly, the operator has the option of confirming the diagnosis before initiating repair action. The operator can confirm the diagnosis with the verify probe procedure. Verify probe is a system software routine, originally developed for the GETS-1000B, that allows the operator to probe around the vicinity of the suspected failure and confirm that all nodes before the suspected failure are good while the nodes beyond the suspected failure are bad. In this manner, the operator confirms that the fault lies between the last good and the first bad node. A good candidate for the fault location is the primary cause of failure listed as a result of searching the LASAR fault dictionary. The operator has the option to probe both the inputs and the outputs of the indicated integrated Circuit (IC) to confirm that the inputs are good and the outputs are bad. The operator begins by specifying the location needed to probe. Verify probe runs the LASAR test patterns and measures the Wizard-I probe (hand-held probe), comparing the probed levels with what was expected by the LASAR simulator for the selected node. The operator is then told whether the node is good or bad and selects the next node to probe accordingly. To aid in determining which IC pins are connected to each other on the UUT, verify probe also displays all fanouts connected to the node just probed as well as all inputs to the IC that drives the selected node.