A design method for cost-effective self-testing checker for optimal d-unidirectional error detecting codes

Unidirectional/asymmetric error codes have extensively been studied, not only from theoretical interest but from application to computer systems or communication systems. Recently, attention has been focused on detecting only d, not all, unidirectional errors, that is, d bits unidirectional error detecting (d-UED) codes. The paper shows a design method for a cost-effective self-testing checker for the optimal d-UED code. The checking policy is to check whether condition of the Borden code satisfies or not. The proposed checker includes the parallel weight counter, the comparator and the modulo adder in which new residue operation is defined and hence this makes the circuit self-testing. These circuits are designed to have all possible input patterns in order to satisfy self-testing property. Finally, the proposed checker has greatly reduced hardware requirements