Welcome to Raspberry Pi 4B repository

!Note:

The maximum continuous input and output voltage of the Raspberry Pi's GPIO pin is 3.3V. Do not connect it directly with other electronic components, otherwise it will damage the Raspberry Pi.

Step 1:Create and open read_gpio.c file

nano read_gpio.c

Step 2: Writing code

#include<stdio.h>
#include<wiringPi.h>  //Import wiringPi.h library

#define Output_Pin 0  //Define Output_Pin as pin 0 of wPi, corresponding to GPIO0
#define Input_Pin 1 //Define Input_Pin as pin1 of wPi, corresponding to GPIO1
int main()
{
printf("This is an example of a raspberry PI pin readingn");
wiringPiSetup();   //Initialize wiringPi
pinMode(Output_Pin,OUTPUT); //Set Output_Pin to output mode
pinMode(Input_Pin,INPUT);  //Set Output_Pin to input mode

printf("Set Output_Pin : Hn");
     digitalWrite(Output_Pin,HIGH); //set Output_Pin output high level

     delay(200);    //delay 200ms
printf("Input_Pin : %dn",digitalRead(Input_Pin)); //Print Input_Pin value
     delay(2000);       //delay 2000ms
    
printf("Set Output_Pin: Ln");
digitalWrite(Output_Pin,LOW); //set Output_Pin output low level
delay(200);
printf("Input_Pin : %dn",digitalRead(Input_Pin)); //Print Input_Pin value
while(1)
{

}
return 0;
}

After writing, press Ctrl + X to exit this file.

The system will prompt you whether you need to save, press Y to save and exit.

Step 3: Compile this .c file.

gcc read_gpio.c -o read_gpio -lwiringPi

Step 4: Connect GPIO0 and GPIO1 by Dupont line.

Step 5: Run this code

./read_gpio

We can see that the InputPin pin changes with the output of OutputPin.