#include <stdio.h> #include <stdlib.h> #include <stdbool.h> #include <unistd.h> #define HIGH 1 #define LOW 0 #define INPUT 1 #define OUTPUT 0 int inputPin = 30; bool digitalPinMode(int pin, int dir){ FILE * fd; char fName[128]; // Exporting the pin to be used if(( fd = fopen("/sys/class/gpio/export", "w")) == NULL) { printf("Error: unable to export pin\n"); return false; } fprintf(fd, "%d\n", pin); fclose(fd); // Setting direction of the pin sprintf(fName, "/sys/class/gpio/gpio%d/direction", pin); if((fd = fopen(fName, "w")) == NULL) { printf("Error: can't open pin direction\n"); return false; } if(dir == OUTPUT) { fprintf(fd, "out\n"); } else { fprintf(fd, "in\n"); } fclose(fd); return true; } int digitalRead(int pin) { FILE * fd; char fName[128]; char val[2]; // Open pin value file sprintf(fName, "/sys/class/gpio/gpio%d/value", pin); if((fd = fopen(fName, "r")) == NULL) { printf("Error: can't open pin value\n"); return false; } fgets(val, 2, fd); fclose(fd); return atoi(val); } int setup() { if (!digitalPinMode(inputPin, INPUT)) return -1; return 0; } int main(void) { if (setup() == -1) { exit(1); } while(1) { int sensorVal; sensorVal = digitalRead(inputPin); printf("sensorVal is %d\n", sensorVal); sleep(1); } return 0; }
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