Functional delay test generation approach using a software prototype of the circuit

Abstract

The paper presents functional delay test generation approach for non-scan synchronous sequential circuits. The non-scan sequential circuit is represented as the iterative logic array model consisting of k copies of the combinational logic of the circuit. The value k defines the number of clock cycles. The software prototype model is used for the representation of the function of the circuit. The faults are considered on the inputs and on the outputs of the model only. The random input stimuli are generated and selected then according to the proposed approach. The experimental results demonstrate the superiority of the delay test stimuli generated at the functional level using the introduced approach against the transition test stimuli obtained at the gate level by deterministic test generator. The functional delay test generation approach especially is useful for the circuits, when the long test sequences are needed in order to detect transition faults.

Design Flow Allowing the Effective Use of Non-scan and Scan-Based Tests

“…Setting the conditions for completing the generation, selection of the correct length of test patterns, setting the best distribution of ones and zeroes for random generation can be carried out on the same principles as during functional test generation. These principles are described in the article [15].…”

“…Only relatively short sequences manage to calculate within a reasonable period of time when using deterministic methods. Therefore, functional test generation techniques are useful, which uses the principle of the selection [15]. Test patterns are generated randomly or according to the given rules.…”

“…Calculation time reduction relates to fault list manipulation. The principles that are used for the generation of functional test can be applied using faults simulation [15]. Fault simulation requires greater resources than the analysis of functional faults.…”

“…Therefore, the following functional test can significantly increase the amount of the detected faults. The method for generating of functional test is described in [15].…”

“…The fourth column contains the data for fault simulation of functional test, that is, the duration of fault simulation (Time(s)), how much clocks required of the selected test patterns to detect new faults (Clocks), and the remaining undetected faults after the functional test (Not detec.). Functional test has been obtained on the basis of the methods described in [15]. Subsequent two columns show data after the selection of the test patterns generated at random and generated similar to the already selected as described in the fifth and sixth sections.…”