ONE-BOARD MICROCOMPUTER

PURPOSE:To make inspection of electric function and maintenance of each functional block easy and to save electric power by providing a bus line split circuit and a power source controlling circuit. CONSTITUTION:The whole system is controlled by an MPU 1, and a storage device consisting of a battery 3 for back-up and a CMOS memory 2 and a bus line 4 are connected to the MPU 1. Functional blocks 7, 10, 13, 16 are connected through bus split circuits 5, 8, 11, 14 that connect or separate to and from the bus line 4, and power source controlling circuits 6, 9, 12, 15 that control make/break of power source of functional blocks 7, 10, 13, 16 separately are connected to functional blocks 7, 10, 13, 16.