| 摘要 |
<p>PROBLEM TO BE SOLVED: To solve problems of current consumption, a processing speed, etc., generated so far when a program was run on an external memory by using a microcomputer which has a CPU and a RAM in the same packet. SOLUTION: The microcomputer 1 incorporates the CPU 2 and the RAM 3 in the same package. The CPU 2 is able to access a ROM 4 and the internal RAM 3 through an address bus. The program that the CPU 2 reads out is stored in the external ROM 4. Further, a program for a process for switching the microcomputer 1 to power-saving mode is also stored as a data group in the external ROM 4. When the microcomputer 1 is switched to the power-saving mode, the data group is copied to a specific area of the internal RAM 3 and then a jump to the head of the area is made to perform the process for switching to the power-saving mode. After the jump to the area of the RAM 3 is made, the external ROM 3 is not active, so the current consumption of the external ROM 4 is suppressed.</p> |
