| 摘要 |
<p>PROBLEM TO BE SOLVED: To surely detect the decrease of a power supply voltage within the range of a power supply voltage in which a microcomputer can be normally operated. SOLUTION: This circuit is provided with a delay circuit 1 whose delay time is the longest in a microcomputer. The output of a logical value '1' of the delay circuit 1 is written in one bit (flag) of the specific address of a flash memory 5. A CPU 6 detects a state that the flag is set as the logical value '1', changes an arithmetic processing speed from a high speed to a low speed, and promotes warning of battery exchange or the like.</p> |
