| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent a display from deviating owing to the contact resistance of a touch panel by providing a voltage holding means which does not vary in voltage abruptly with the contact resistance. SOLUTION: When input is detected, an interrupt is initiated with an input detection signal TPPDDX and an AD converter 22 starts AD conversion. As for a Y axis, a voltage divided by the touch panel 1 is taken out of a terminal TPL and an AD converter 22 converts it into a digital voltage. At this time, a switch TM1 is turned ON to charge a capacitor C1 with the voltage divided by the touch panel. As for an X axis, a divided voltage is similarly taken out of a terminal TPD and converted by the AD converter 22 into a digital voltage. At this time, a switch TM2 is turned ON to charge a capacitor C2 with the divided voltage. Consequently, even if the contact resistance increases abruptly as an input position moves, a stable state is held with the electric charges accumulated in the capacitor without any variation in the input of the AD conversion.</p> |
