Comments on systematic procedure for test generation of PAL based circuits

Comments on the test generation algorithm 1 given in a previous paper (see ibid., vol.136, no.2, p.142-9 (1989)), for single S-fault detection are presented. It is shown that the test vectors belonging to the test set generated by algorithm 1 can not detect certain faults. To generate a test set T, detect all single faults in a given PAL modification to the algorithm 1 is suggested. Furthermore, it is shown that some of the conclusions drawn on multiple fault detection capabilities of a single fault test set T discussed in Section 7 of that paper do not hold good in the presence of certain multiple faults with a four way masking cycle.