| 摘要 |
<p>PURPOSE:To reduce power consumption without generating an operation failure by moving to a sleep mode at the time of detecting that a key operation is not operated, and a prescribed condition is fulfilled. CONSTITUTION:Scan signals are successively inputted from scan terminals 12c of a microcomputer 12 to the bases of a switching transistors 14a-14c, so that key scan can be attained. At the same time, the microcomputer 12 monitors input signals from each detection line 11a-11c of a key matrix 11, and detects a valid key whose state is changed among each key 13. At that time, the scan data are compared with the scan data at the time of previous key scan, and when the valid key 13 whose state is changed or the key 13 which is left turned on is absent, and data are absent in a key buffer, the sleep mode is obtained. Afterwards, when any key 13 is operated, or when data input from a computer main body 15 is operated, the sleep mode is released by an interrupting instruction, and the key scan is operated again.</p> |
