104 lines
2.1 KiB
C
104 lines
2.1 KiB
C
#include <stdio.h>
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#include <fcntl.h>
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#include <string.h>
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#include <time.h>
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#include <unistd.h>
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#define BASEPATH "/sys/class/gpio/"
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#define GPIO_FOLDER "gpio%s/"
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#define PIN_BUTTON "17"
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#define PIN_LED "18"
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#define LED_ON 0
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#define LED_OFF 1
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#define BUTTON_PRESSED 0
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#define BUTTON_RELEASED 1
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void writeFile(char *filename, char *buffer, size_t count)
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{
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int fd = open(filename, O_WRONLY);
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write(fd, buffer, count);
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close(fd);
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}
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void registerPin(char *pin)
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{
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writeFile(BASEPATH "export", pin, strlen(pin));
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}
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void freePin(char *pin)
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{
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writeFile(BASEPATH "unexport", pin, strlen(pin));
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}
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void setDirection(char *pin, char *direction, int dirlen)
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{
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char path[50];
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sprintf(path, BASEPATH GPIO_FOLDER "direction", pin);
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writeFile(path, direction, dirlen);
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}
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void registerInput(char *pin)
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{
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registerPin(pin);
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setDirection(pin, "in", 2);
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}
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void registerOutput(char *pin)
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{
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registerPin(pin);
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setDirection(pin, "out", 3);
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}
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int readInput(char *pin)
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{
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char path[50];
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int state;
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sprintf(path, BASEPATH GPIO_FOLDER "value", pin);
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FILE *fd = fopen(path, "r");
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fscanf(fd, "%i", &state);
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fclose(fd);
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return state;
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}
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void writeOutput(char *pin, int state)
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{
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char path[50];
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sprintf(path, BASEPATH GPIO_FOLDER "value", pin);
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FILE *fd = fopen(path, "w");
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fprintf(fd, "%i", state);
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fclose(fd);
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}
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int main()
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{
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struct timespec sleeptime, sleepremain;
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int oldstate = BUTTON_PRESSED;
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int state;
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int count = 0;
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registerInput(PIN_BUTTON);
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registerOutput(PIN_LED);
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sleeptime.tv_sec = 0;
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sleeptime.tv_nsec = 1000000;
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nanosleep(&sleeptime, &sleepremain);
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while (1)
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{
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state = readInput(PIN_BUTTON);
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if (state == BUTTON_PRESSED && oldstate == BUTTON_RELEASED)
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{
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count++;
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printf("Number of button pushes: %i\n", count);
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}
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if (state == BUTTON_PRESSED)
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writeOutput(PIN_LED, LED_ON);
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else
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writeOutput(PIN_LED, LED_OFF);
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oldstate = state;
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nanosleep(&sleeptime, &sleepremain);
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}
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}
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