Добавлен пример для работы прерывания по gpio

examples/gpio-interrupt.c

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+/* Demonstration C GPIO interrupt handling routine for Raspberry Pi
+
+This is a modified code found at https://github.com/phil-lavin/raspberry-pi-gpio-interrupt
+
+The program displays a notice whenever you:
+  -turn on the Raspberry Pi's pin 11 (apply 3.3V),
+  -turn the pin off.
+
+This routine uses wiringPi library (follow the installation instructions at wiringpi.com),
+and should be compiled with a command:
+
+gcc source_filename -o executable_filename -lwiringPi
+
+You must have root privileges to run it - I don't know any workaround yet:
+
+sudo ./executable_filename
+
+Then the program displays a notice whenever you turn the GPIO pin 11 on and off.
+It runs as an infinite loop and you can cancel it by pressing ctrl-C.
+*/
+
+#include <stdlib.h>
+#include <unistd.h>
+#include <stdio.h>
+#include <sys/time.h>
+#include <wiringPi.h>
+
+// Which GPIO pin we're using. For this program we'll use physical pin numbers.
+#define PIN 27
+
+// How much time a change must be since the last in order to count as a change
+// (in microseconds); allows to avoid generating interrupts on contact bouncing etc.
+#define IGNORE_CHANGE_BELOW_USEC 10000
+
+// Current state of the pin
+static volatile int state;
+
+// Time of last change
+struct timeval last_change;
+
+
+// Handler for interrupt
+void handle(void) {
+	struct timeval now;
+	static __uint64_t cnt;
+	unsigned long diff;
+	//gettimeofday(&now, NULL);
+	state = digitalRead(PIN);
+	printf("-->%d %d\n", ++cnt, state);
+	return;
+
+	// Time difference in microseconds
+	diff = (now.tv_sec * 1000000 + now.tv_usec) - (last_change.tv_sec * 1000000 + last_change.tv_usec);
+
+	// Filter any changes in intervals shorter than diff (like contact bouncing etc.):
+	/*
+	if (diff > IGNORE_CHANGE_BELOW_USEC) {
+
+                // Check whether the last state was on or off:
+		if (state) {
+                        // Print info to console:
+			printf("Input goes off\n");
+                        // You can add some code to do when input goes off here...
+		}
+		else {
+			// Print info to console:
+                        printf("Input goes on\n");
+                        // Add code to do when input goes on here...
+		}
+
+		// Change the "state" variable value:
+                state = !state;
+	}
+	*/
+    // Store the time for last state change:
+	last_change = now;
+}
+
+int main(void) {
+	// Init  -- use the physical pin number on RPi P1 connector
+	if (wiringPiSetup() == -1)
+	{
+		printf("ошибка wiringPiSetup()\n");
+		exit(1);
+	}
+
+	// Set pin to input in case it's not
+	pinMode(PIN, INPUT);
+	pullUpDnControl(PIN, PUD_UP);
+
+	// Time now
+	gettimeofday(&last_change, NULL);
+
+	// Bind to interrupt
+	wiringPiISR(PIN, INT_EDGE_RISING, &handle);
+
+	// Get initial state of pin
+	state = digitalRead(PIN);
+
+        // Feedback for user that the program has started, depending on input state:
+	if (state) {
+		printf("Started! Initial state is on\n");
+	}
+	else {
+		printf("Started! Initial state is off\n");
+	}
+
+	// Waste time but not CPU
+	for (;;) {
+		sleep(1);
+		state = digitalRead(PIN);
+	}
+}