JPS6476146A - Bus coupling arbitrating system - Google Patents

Abstract

PURPOSE:To eliminate the load of a program by providing a priority at a mutual request when the request of the mutual use collides, executing the bus cycle error information to a requester having a lower priority and processing the request having a higher priority earlier. CONSTITUTION:A bus coupling arbitrating system CONAB1, when a request from a processor CPU1 and a CPU2 is received, acknowledges the request with the higher priority by the decision of the priority circuit of the internal part of the bus coupling arbitrating system CNAB 1, and executes a bus cycle error information to the request with the lower priority. The processor CPU 2 to receive the bus cycle error information stops the bus cycle by generating an error at the bus cycle execution, and a bus action is stopped until the bus cycle error is released. During the period, the bus cycle of the processor CPU1 with the higher priority operates a local memory MEM2 at the processor CPU2 side through a bus coupling part BUSCN1.