A Totally Self-Checking Checker for Borden's Code

It is well known that a large number of errors in VLSI circuits are unidirectional in nature. It has been shown that the [n/2 J-out-of-n codes are the optimal codes for detecting all unidirectional errors. Recently, attention has been focused on detecting only t, not all, unidirectional errors. Borden has shown that a code consisting of all length n words whose weight (number of bits which are 1) is congruent to [n/2] modulo (t + 1) is an optimal r-unidirectional error detecting (f-UED) code. For a code to be employed in a self-checking system, a self-checking checker must exist for it. The totally self-checking (TSC) checker is one such checker. Many designs for TSC checkers exist for m-out-of-n codes. However, no work has been reported on the design of a TSC checker for Borden's code. In this paper we present such a design. This design should lead to greater applicability of Borden's code to selfchecking systems.