From 3e1f99e24d581b9bc9a7589117203c6f1dedb6a5 Mon Sep 17 00:00:00 2001
From: phylax2020 <severin.hoffmann@t-online.de>
Date: Tue, 28 Jan 2025 22:30:54 +0100
Subject: [PATCH] new example isr_debounce.c

---
 examples/isr_debounce.c | 118 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 118 insertions(+)
 create mode 100644 examples/isr_debounce.c

diff --git a/examples/isr_debounce.c b/examples/isr_debounce.c
new file mode 100644
index 0000000..5c6ca8b
--- /dev/null
+++ b/examples/isr_debounce.c
@@ -0,0 +1,118 @@
+/*
+ * isr_debounce.c:
+ *	Wait for Interrupt test program  WiringPi >=3.2 - ISR method
+ *
+ *
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+#include <stdlib.h>
+#include <wiringPi.h>
+#include <wpiExtensions.h>
+#include <unistd.h>
+// #include <sys/time.h>
+#include <time.h>
+
+#define BOUNCETIME 300
+#define TIMEOUT    10000
+//*************************************
+// BCM pins
+// IRQpin : setup as input with internal pullup. Connected with push button to GND with 1K resistor in series.
+// OUTpin : connected to a LED with 470 Ohm resistor in series to GND. Toggles LED with every push button pressed.
+//*************************************
+#define IRQpin     16
+#define OUTpin     12 
+
+int toggle = 0;
+
+/*
+ * myInterrupt:
+ *********************************************************************************
+ */
+
+static void wfi (unsigned int gpio, long long int timestamp) { 
+//  struct timeval now;
+  long long int timenow, diff;
+  struct timespec curr;
+
+  if (clock_gettime(CLOCK_MONOTONIC, &curr) == -1) {
+        printf("clock_gettime error");
+        return;
+  }
+  
+  timenow = curr.tv_sec * 1000000LL + curr.tv_nsec/1000L; // convert to microseconds
+  diff = timenow - timestamp;
+  
+  printf("gpio BCM = %d, IRQ timestamp = %lld microseconds, timenow = %lld, diff = %lld\n", gpio, timestamp, timenow, diff);
+  if (toggle == 0) {
+    digitalWrite (OUTpin, HIGH) ;
+    toggle = 1;
+  }
+  else {
+    digitalWrite (OUTpin, LOW) ; 
+    toggle = 0;
+  }
+}
+
+
+
+int main (void)
+{
+  int major, minor;
+  long long int ret;
+  
+  wiringPiVersion(&major, &minor);
+
+  printf("\nISR debounce test (WiringPi %d.%d)\n\n", major, minor);
+  
+  wiringPiSetupGpio() ;
+
+  pinMode(IRQpin, INPUT);
+  
+  // pull up/down mode (PUD_OFF, PUD_UP, PUD_DOWN) => down
+  pullUpDnControl(IRQpin, PUD_UP);
+
+  pinMode(OUTpin, OUTPUT);
+  digitalWrite (OUTpin, LOW) ;
+  
+  // test waitForInterrupt
+
+  ret = waitForInterruptInit (IRQpin, INT_EDGE_FALLING);
+  if (ret < 0) {
+    printf("waitForInterruptInit returned error %d\n", ret);
+    pinMode(OUTpin, INPUT);
+    return 0;
+  }
+  
+  printf("Testing waitForInterrupt IRQ @ GPIO%d, timeout is %d\n", IRQpin, TIMEOUT);  
+  ret = waitForInterrupt(IRQpin, TIMEOUT, 0);
+  if (ret < 0) {
+    printf("waitForInterrupt returned error %lld\n", ret);
+    wiringPiISRStop (IRQpin) ;  
+    pinMode(OUTpin, INPUT);
+    return 0;    
+  }
+  else if (ret == 0) {
+    printf("waitForInterrupt timed out %lld\n\n", ret);
+    wiringPiISRStop (IRQpin) ;  
+  }   
+  else {
+    printf("waitForInterrupt returned success. ret = %lld\n\n", ret);     
+    wiringPiISRStop (IRQpin) ;  
+  }
+  
+  printf("Testing IRQ @ GPIO%d with trigger @ GPIO%d falling edge and bouncetime %d ms. Toggle LED @ OUTpin on IRQ.\n\n", IRQpin, IRQpin, BOUNCETIME, OUTpin);
+  printf("To stop program hit return key\n\n");
+  
+  wiringPiISR (IRQpin, INT_EDGE_FALLING, &wfi, BOUNCETIME) ; 
+ 
+//  sleep(30);
+  getc(stdin);
+  
+  wiringPiISRStop (IRQpin) ;  
+  pinMode(OUTpin, INPUT);
+
+  return 0 ;  
+}
\ No newline at end of file