| 摘要 |
<p>PURPOSE:To reduce the burden of a CPU by performing only minimum required scanning to eliminate unnecessary scanning whether a touch key is inputted or not. CONSTITUTION:When a touch key is not inputted and a light beam is not intercepted, successive driving scanning only in the Y direction is repeated; and if a touch key is inputted, a CPU 9 detects the input of the touch key by the change of the output of a light receiving element in an optical path where the light beam is intercepted, and Y-direction scan address data Ym is written in a memory 5. Next, successive scanning in the Y direction is stopped and that in the X direction is started, and X-direction scan address data Xn is written in a memory 6 in accordance with the change of the output of the light receiving element in the optical path where the light beam is intercepted. while the light beam is intercepted, scanning of scan addresses Ym and Xn and write of scan addresses Ym and Xn in memories 7 and 8 are repeated. When interception of the light beam is released, memories 7 and 8 are cleared with respect to scan addresses Ym and Xn.</p> |
