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/*
* isr.c:
* Wait for Interrupt test program - ISR method
*
* How to test:
* Use the SoC's pull-up and pull down resistors that are avalable
* on input pins. So compile & run this program (via sudo), then
* in another terminal:
* gpio mode 0 up
* gpio mode 0 down
* at which point it should trigger an interrupt. Toggle the pin
* up/down to generate more interrupts to test.
*
* Copyright (c) 2013 Gordon Henderson.
***********************************************************************
* This file is part of wiringPi:
* https://projects.drogon.net/raspberry-pi/wiringpi/
*
* wiringPi is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published by
* the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* wiringPi is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with wiringPi. If not, see <http://www.gnu.org/licenses/>.
***********************************************************************
*/
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <stdlib.h>
#include <wiringPi.h>
// What GPIO input are we using?
// This is a wiringPi pin number
#define BUTTON_PIN 0
// globalCounter:
// Global variable to count interrupts
// Should be declared volatile to make sure the compiler doesn't cache it.
static volatile int globalCounter = 0 ;
/*
* myInterrupt:
*********************************************************************************
*/
void myInterrupt (void)
{
++globalCounter ;
}
/*
*********************************************************************************
* main
*********************************************************************************
*/
int main (void)
{
int myCounter = 0 ;
if (wiringPiSetup () < 0)
{
fprintf (stderr, "Unable to setup wiringPi: %s\n", strerror (errno)) ;
return 1 ;
}
if (wiringPiISR (BUTTON_PIN, INT_EDGE_FALLING, &myInterrupt) < 0)
{
fprintf (stderr, "Unable to setup ISR: %s\n", strerror (errno)) ;
return 1 ;
}
for (;;)
{
printf ("Waiting ... ") ; fflush (stdout) ;
while (myCounter == globalCounter)
delay (100) ;
printf (" Done. counter: %5d\n", globalCounter) ;
myCounter = globalCounter ;
}
return 0 ;
}