| 摘要 |
PURPOSE:To improve the using efficiency of an incorporated peripheral function and also to attain a multi-CPU system having high processing efficiency, by attaining external access to the peripheral function incorporated to a microcomputer. CONSTITUTION:When a master request signal MRQ is delivered to a microcomputer 10 from an external CPU20, the working of a CPU12 is stopped and at the same time the CPU12 is separated electrically from an internal address bus A1, etc. Furthermore, bidirectional buffers 18a and 18c are switched to the inner direction from the outer direction. While the direction of a bidirectional buffer 18d is controlled by a read/write control signal R/W2 supplied from the outside. Thus direct access is possible to the peripheral function incorporated to the computer 10 from the CPU20. This improves the using efficiency of said peripheral function as well as the processing efficiency of a multi-CPU system. |
