COPROCESSOR COUPLING SYSTEM

摘要

PURPOSE:To transfer data between a memory and a coprocessor CP in one bus cycle by adding CPS and CPCYCL pins besides memory access signal pins of a microprocessor to select the CP simultaneously with memory access. CONSTITUTION:When an operand is transferred from a memory 3 to a CP 2, a microprocessor (MPU) 1 asserts not only a memory read signal but also a signal (CPCYCL) indicating the validity of coprocessor data and instructs the CP 2 to take in data, and the operand is transferred from the memory to the CP in one bus cycle. When data is transferred from the CP 2 to the memory 3, the MPU 1 asserts not only a memory write signal but also the signal (CPCYCL) and instructs the CP 2 to output data, and the data is transferred from the CP 2 to the memory 3 in one bus cycle.