| 摘要 |
PROBLEM TO BE SOLVED: To suppress power consumption and to speedily and precisely determine an operation key corresponding to key operation, while making load due to software processing during key scan operation dispensable.SOLUTION: A key scan circuit comprises: a key matrix 17d; a register part 17b for storing a scan frequency which determines a state of key on and a scan frequency which determines a state of key off; and a key controller part 17a which consecutively performs key-scan of the key matrix 17d by using a plurality of frequencies as one pair by using a greater one of stored respective determined frequencies of the key on and the key off, determines the key on concerning a key in which the key on is detected by the stored key on scan frequencies during the key-scans in a pair, and determines the key off concerning a key in which the key off is detected by the stored key off scan frequencies concerning the key in which the key on has been determined. |
