Interface circuit between 4-wire resistive touch screen and ADS7846

For 4-wire resistive touch screen with. Interface circuit of ADS7846 .
    The ADS7846 chip contains analog electronic switches and successive approximation A/D converters. By switching the on-chip analog switch, connect the X+ (or
Y+) terminal to the positive power supply (‰), the x- (or Yr) terminal to the ground (CND), and connect the Y+ (or ) terminal
is connected to the input terminal of the A/D converter in differential form. When the pen touches different positions of the touch screen,
the voltage values ​​input from the Y+ (or X+) terminal to the on-chip A/D converter are different. After the input voltage is converted by the on-chip A/D, the Y (or Output value, and the output value
has an approximately linear relationship with the stroke point position. Therefore, the output values ​​​​X and Y (ie, coordinate values) of ADS 7846 can describe the position of the pen touch point on the touch screen
.