A one chip microcomputer.

摘要

A one ship microcomputer comprises:
a central processing unit (CPU 1) having arithmetic, logic and control units; a random access memory (RAM 3) for storing intermediate data with instructions processed by the central processing unit (CPU 1); means (4, 23) for carrying first data processed by the central processing unit (CPU 1); a direct memory access controller (DMAC 2) controlled by the central processing unit (CPU 1) for providing a read out of second data stored in a predetermined area of the random access memory (RAM 3); means (9, 21) for carrying the second data stored in the predetermined area of the random access memory (RAM 3); terminal means (P) coupled to said means for carrying the first and second data to provide an output for the first data during a central processing unit operating mode and for the second data during a direct memory access operating mode; and, a time division means (5) controlled by the direct memory access controller (DMAC 2) for transmitting the first or the second data to the terminal means (P). This has the advantage that a direct transfer can take place between the RAM 3 and the outside without the provision of any additional terminals.