DATA PROCESSING SYSTEM AND MICROCOMPUTER

摘要

PROBLEM TO BE SOLVED: To provide a data processing system which detects a change in a capacitance of a touch sensor with high accuracy by using a microcomputer.;SOLUTION: A voltage division node of a capacitance division circuit (CDC1) and a capacitance electrode of a touch sensor (8) are connected to an external input terminal (PG2) of a microcomputer (1) having a central processing unit (21), an analog-digital converting circuit (21), and an input buffer (101). The capacitance division circuit inputs a voltage signal obtained at the voltage division node by dividing an AC voltage to the analog-digital converting circuit via the input buffer, and the analog-digital converting circuit converts the voltage signal into digital data. At this time, the input buffer hides an input capacitance of the analog-digital converting circuit so that the input capacitance is not seen from the external input terminal. This makes the input capacitance of the analog-digital converting circuit not affect the detection accuracy of the divided voltage changed by a touch on the touch sensor.;COPYRIGHT: (C)2010,JPO&INPIT