Self-Testing the Motorola MC6804P2

The internal serial architecture of the MC6804P2??Motorola´s smallest 8-bit, single-chip microcomputer??and the need to minimize test costs led to development of a built-in self-test scheme. The self test is based on a ROM-driven signature analysis technique that utilizes polynomial division to compress lengthy output responses (or signatures) to much smaller results. On-chip signature analysis is an attractive alternative to conventional testing. The signature register, associated control logic, and 288 bytes of self-test ROM occupy less than 5 percent of total chip area. High fault coverage and support for parametric testing with minimal chip area are keys to successful application. This was the authors´ first experience with on-chip signature analysis in a commercial MOS microcomputer, but the usefulness of the technique for testing and data compression will undoubtedly find its way into future Motorola products.