| 摘要 |
PURPOSE:To easily check trouble with only switching operation of a switch by storing a system diagnostic program in one of divided memory area and switching these memory areas with the switch. CONSTITUTION:A system program and the diagnostic program are stored in the lower area and the upper area of a memory divided into two memory areas respectively. When a changeover switch 7 connected to the most significant bit of an address bus A is turned on, a microcomputer 2 accesses the lower area of the memory 3 and the system program is started. When the switch 7 is turned off, the most significant bit of the address bus is set to the high level and the microcomputer 2 accesses the upper area of the memory 3. That is, the diagnostic program is started. Thus, the memory area is switched to the memory area of the diagnostic program at the time of trouble of the system to easily check trouble. |
