Trustworthy bus arbiter by alternate-data retry

A simple trustworthy bus arbiter by alternate-data retry is proposed. Trustworthiness is considered to be such a property that system responses are always trustworthy whether there exist faults or not in the system. The arbiter has two phase operations to select a parallel decision decentralized arbiter which is used in Futurebus, MultibusII and so on. The presented scheme does not permit that two or more modules are selected as bus masters to cause a fatal system operation. The arbiter presented by alternate-data retry is operated in a specially defined Id code space. Three self complementary-codes named complementary mirrored-code, reversible-ordered-code and continuous two-bit changing code are presented to be applied to the proposed arbiter