4-Wire Touch Screen Interface Step 3

Step 3: Programming the arduino

How it works ?

It works in 2 steps

1. Measure X axis Voltage

To measure X axis voltage

a. We are going to measure voltage on Y1

   pinMode(Y1,INPUT);

 b. Make Y2 Tristate

   pinMode(Y2,INPUT); 

   digitalWrite(Y2,LOW);

c. Form a voltage divider in X1(+5V) and X2(GND)

   pinMode(X1,OUTPUT);

   digitalWrite(X1,HIGH);

   pinMode(X2,OUTPUT);

   digitalWrite(X2,LOW);

d. Read the ADC from Y1 pin

  X = (analogRead(Y1))/(1024/XYresolution);

2. Similarly Measure Y axis Voltage

To measure Y axis voltage

a. We are going to measure voltage on X1

   pinMode(X1,INPUT);

 b. Make X2 Tristate

   pinMode(X2,INPUT); 

   digitalWrite(X2,LOW);

c. Form a voltage divider in Y1(+5V) and Y2(GND)

   pinMode(Y1,OUTPUT);

   digitalWrite(Y1,HIGH);

   pinMode(Y2,OUTPUT);

   digitalWrite(Y2,LOW);

d. Read the ADC from X1 pin

  Y = (analogRead(X1))/(1024/Yresolution); 

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