initial cleanup and mapping

examples/wfi.c

@@ -0,0 +1,161 @@
+/*
+ * wfi.c:
+ *	Wait for Interrupt test program
+ *
+ *	This program demonstrates the use of the waitForInterrupt()
+ *	function in wiringPi. It listens to a button input on
+ *	BCM_GPIO pin 17 (wiringPi pin 0)
+ *
+ *	The biggest issue with this method is that it really only works
+ *	well in Sys mode.
+ *
+ *	Jan 2013: This way of doing things is sort of deprecated now, see
+ *	the wiringPiISR() function instead and the isr.c test program here.
+ *
+ * Copyright (c) 2012-2013 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 <stdlib.h>
+#include <wiringPi.h>
+
+// A 'key' which we can lock and unlock - values are 0 through 3
+//	This is interpreted internally as a pthread_mutex by wiringPi
+//	which is hiding some of that to make life simple.
+
+#define	COUNT_KEY	0
+
+// What BCM_GPIO input are we using?
+
+#define	BUTTON_PIN	17
+
+// Debounce time in mS
+
+#define	DEBOUNCE_TIME	100
+
+
+// globalCounter:
+//	Global variable to count interrupts
+//	Should be declared volatile to make sure the compiler doesn't cache it.
+
+static volatile int globalCounter = 0 ;
+
+
+/*
+ * waitForIt:
+ *	This is a thread created using the wiringPi simplified threading
+ *	mechanism. It will wait on an interrupt on the button and increment
+ *	a counter.
+ *********************************************************************************
+ */
+
+PI_THREAD (waitForIt)
+{
+  int state = 0 ;
+  int debounceTime = 0 ;
+
+  (void)piHiPri (10) ;	// Set this thread to be high priority
+
+  for (;;)
+  {
+    if (waitForInterrupt (BUTTON_PIN, -1) > 0)	// Got it
+    {
+// Bouncing?
+
+      if (millis () < debounceTime)
+      {
+	debounceTime = millis () + DEBOUNCE_TIME ;
+	continue ;
+      }
+
+// We have a valid one
+
+      state ^= 1 ;
+
+      piLock (COUNT_KEY) ;
+	++globalCounter ;
+      piUnlock (COUNT_KEY) ;
+
+// Wait for key to be released
+
+      while (digitalRead (BUTTON_PIN) == LOW)
+	delay (1) ;
+
+      debounceTime = millis () + DEBOUNCE_TIME ;
+    }
+  }
+}
+
+
+/*
+ * setup:
+ *	Demo a crude but effective way to initialise the hardware
+ *********************************************************************************
+ */
+
+void setup (void)
+{
+
+// Use the gpio program to initialise the hardware
+//	(This is the crude, but effective)
+
+  system ("gpio edge 17 falling") ;
+
+// Setup wiringPi
+
+  wiringPiSetupSys () ;
+
+// Fire off our interrupt handler
+
+  piThreadCreate (waitForIt) ;
+
+}
+
+
+/*
+ * main
+ *********************************************************************************
+ */
+
+int main (void)
+{
+  int lastCounter = 0 ;
+  int myCounter   = 0 ;
+
+  setup () ;
+
+  for (;;)
+  {
+    printf ("Waiting ... ") ; fflush (stdout) ;
+
+    while (myCounter == lastCounter)
+    {
+      piLock (COUNT_KEY) ;
+	myCounter = globalCounter ;
+      piUnlock (COUNT_KEY) ;
+      delay (500) ;
+    }
+
+    printf (" Done. myCounter: %5d\n", myCounter) ;
+    lastCounter = myCounter ;
+  }
+
+  return 0 ;
+}