Design of a reliable and self-testing VLSI datapath using residue coding techniques

The testing of VLSI circuits is becoming progressively more difficult as device densities increase. This has brought about several proposals for designing VLSI circuits with testability built in. A method is presented in the paper for the design of easily testable VLSI circuits with a view to producing fault tolerant systems. A microprocessor datapath is used to illustrate the technique. The method used for checking the VLSI devices is an error detecting code, in this case a residue code. Residue codes offer several advantages over linear block codes for providing testability in a wide range of VLSI circuits. A detailed evaluation of the increase in chip area required to produce a self testing chip is also given in the paper.