Big update here.

delayMicrosecondsHard re-written - again.
Added a serialRead example program, and added in the okLed
to the examples too.
Updated/checked some of the GPIO/PWM code.
Added in some experimental servo and tone generating code and
and example or 2.
Tweaks to the gpio command to correctly load the I2C modules too.

examples/Makefile

@@ -30,16 +30,19 @@ INCLUDE	= -I/usr/local/include
 CFLAGS	= $(DEBUG) -Wall $(INCLUDE) -Winline -pipe
 
 LDFLAGS	= -L/usr/local/lib
-LIBS    = -lwiringPi
+LDLIBS    = -lwiringPi
 
 # Should not alter anything below this line
 ###############################################################################
 
-SRC	=	test1.c test2.c speed.c lcd.c wfi.c piface.c gertboard.c nes.c delayTest.c softPwm.c
+SRC	=	test1.c test2.c speed.c lcd.c wfi.c		\
+		piface.c gertboard.c nes.c			\
+		pwm.c tone.c servo.c				\
+		delayTest.c serialRead.c okLed.c
 
-OBJ	=	test1.o test2.o speed.o lcd.o wfi.o piface.o gertboard.o nes.o delayTest.o softPwm.o
+OBJ	=	$(SRC:.c=.o)
 
-BINS	=	test1 test2 speed lcd wfi piface gertboard nes delayTest softPwm
+BINS	=	$(SRC:.c=)
 
 all:	
 	@cat README.TXT
@@ -48,43 +51,59 @@ all:
 
 test1:	test1.o
 	@echo [link]
-	$(CC) -o $@ test1.o $(LDFLAGS) $(LIBS)
+	@$(CC) -o $@ test1.o $(LDFLAGS) $(LDLIBS)
 	
 test2:	test2.o
 	@echo [link]
-	$(CC) -o $@ test2.o $(LDFLAGS) $(LIBS)
+	@$(CC) -o $@ test2.o $(LDFLAGS) $(LDLIBS)
 
 speed:	speed.o
 	@echo [link]
-	$(CC) -o $@ speed.o $(LDFLAGS) $(LIBS)
+	@$(CC) -o $@ speed.o $(LDFLAGS) $(LDLIBS)
 
 lcd:	lcd.o
 	@echo [link]
-	$(CC) -o $@ lcd.o $(LDFLAGS) $(LIBS)
+	@$(CC) -o $@ lcd.o $(LDFLAGS) $(LDLIBS)
 
 wfi:	wfi.o
 	@echo [link]
-	$(CC) -o $@ wfi.o $(LDFLAGS) $(LIBS) -lpthread
+	@$(CC) -o $@ wfi.o $(LDFLAGS) $(LDLIBS)
 
 piface:	piface.o
 	@echo [link]
-	$(CC) -o $@ piface.o $(LDFLAGS) $(LIBS) -lpthread
+	@$(CC) -o $@ piface.o $(LDFLAGS) $(LDLIBS) -lpthread
 
 gertboard:	gertboard.o
 	@echo [link]
-	$(CC) -o $@ gertboard.o $(LDFLAGS) $(LIBS) -lm
+	@$(CC) -o $@ gertboard.o $(LDFLAGS) $(LDLIBS) -lm
 
 nes:	nes.o
 	@echo [link]
-	$(CC) -o $@ nes.o $(LDFLAGS) $(LIBS) -lm
+	@$(CC) -o $@ nes.o $(LDFLAGS) $(LDLIBS) -lm
 
-softPwm:	softPwm.o
+pwm:	pwm.o
 	@echo [link]
-	$(CC) -o $@ softPwm.o $(LDFLAGS) $(LIBS) -lm -lpthread
+	@$(CC) -o $@ pwm.o $(LDFLAGS) $(LDLIBS) -lm -lpthread
 
 delayTest:	delayTest.o
 	@echo [link]
-	$(CC) -o $@ delayTest.o $(LDFLAGS) $(LIBS)
+	@$(CC) -o $@ delayTest.o $(LDFLAGS) $(LDLIBS)
+
+serialRead:	serialRead.o
+	@echo [link]
+	@$(CC) -o $@ serialRead.o $(LDFLAGS) $(LDLIBS)
+
+okLed:	okLed.o
+	@echo [link]
+	@$(CC) -o $@ okLed.o $(LDFLAGS) $(LDLIBS)
+
+tone:	tone.o
+	@echo [link]
+	@$(CC) -o $@ tone.o $(LDFLAGS) $(LDLIBS)
+
+servo:	servo.o
+	@echo [link]
+	@$(CC) -o $@ servo.o $(LDFLAGS) $(LDLIBS)
 
 
 .c.o:
@@ -92,7 +111,7 @@ delayTest:	delayTest.o
 	@$(CC) -c $(CFLAGS) $< -o $@
 
 clean:
-	rm -f $(OBJ) *~ core tags test1 test2 speed lcd wfi piface gertboard nes delayTest softPwm
+	rm -f $(OBJ) *~ core tags $(BINS)
 
 tags:	$(SRC)
 	@echo [ctags]

examples/delayTest.c

@@ -3,30 +3,24 @@
 #include <unistd.h>
 #include <wiringPi.h>
 
-#include <time.h>
-#include <sys/types.h>
 #include <sys/time.h>
 
 #define	CYCLES	1000
-#define	DELAY	99
 
 int main()
 {
   int x ;
   struct timeval t1, t2 ;
-  long long    t ;
-  unsigned int max, min ;
-
-  unsigned int values [CYCLES] ;
-
-  max = 0 ;
-  min = 1000000 ;
+  int t ;
+  int max, min ;
+  int del ;
+  int underRuns, overRuns, exactRuns, total ;
+  int descheds ;
 
   if (wiringPiSetup () == -1)
     return 1 ;
 
-  piHiPri (10) ;
-  sleep (1) ;
+  piHiPri (10) ; sleep (1) ;
 
 // Baseline test
 
@@ -34,35 +28,56 @@ int main()
   gettimeofday (&t2, NULL) ;
 
   t = t2.tv_usec - t1.tv_usec ;
-  printf ("Baseline test: %lld\n", t);
+  printf ("Baseline test: %d\n", t);
 
-  for (x = 0 ; x < CYCLES ; ++x)
+  for (del = 1 ; del < 200 ; ++del)
   {
-    gettimeofday (&t1, NULL) ;
-    delayMicroseconds (DELAY) ;
-    gettimeofday (&t2, NULL) ;
-      
-    t = t2.tv_usec - t1.tv_usec ;
-    if (t > max) max = t ;
-    if (t < min) min = t ;
-    values [x] = t ;
-  }
+    underRuns = overRuns = exactRuns = total = 0 ;
+    descheds = 0 ;
+    max = del ;
+    min = del ;
 
-  printf ("Done: Max: %d, min: %d\n", max, min) ;
+    for (x = 0 ; x < CYCLES ; ++x)
+    {
+      for (;;)				// Repeat this if we get a delay over 999uS
+      {					// -> High probability Linux has deschedulled us
+	gettimeofday (&t1, NULL) ;
+	  delayMicroseconds (del) ;
+	gettimeofday (&t2, NULL) ;
 
-  for (x = 0 ; x < CYCLES ; ++x)
-  {
-    printf ("%4d", values [x]) ;
-    if (values [x] > DELAY)
-      printf (".") ;
-    else if (values [x] < DELAY)
-      printf ("-") ;
-    else
-      printf (" ") ;
-    if (((x + 1) % 20) == 0)
-      printf ("\n") ;
+	if (t2.tv_usec < t1.tv_usec)	// Counter wrapped
+	  t = (1000000 + t2.tv_usec) - t1.tv_usec;
+	else
+	  t = t2.tv_usec - t1.tv_usec ;
+	if (t > 999)
+	{
+	  ++descheds ;
+	  continue ;
+	}
+	else
+	  break ;
+      }
+
+      if (t > max)
+      {
+        max = t ;
+	++overRuns ;
+      }
+      else if (t < min)
+      {
+	min = t ;
+	++underRuns ;
+      }
+      else
+	++exactRuns ;
+
+      total += t ;
+    }
+    printf ("Delay: %3d. Min: %3d, Max: %3d, Unders: %3d, Overs: %3d, Exacts: %3d, Average: %3d,  Descheds: %2d\n",
+	del, min, max, underRuns, overRuns, exactRuns, total / CYCLES,  descheds) ;
+    fflush (stdout) ;
+    delay (1) ;
   }
-  printf ("\n") ;
 
   return 0 ;
 }

examples/okLed.c

@@ -0,0 +1,65 @@
+/*
+ * okLed:
+ *      Make the OK LED on the Pi Pulsate...
+ *    Copyright (c) 2012 gordon Henderson, but please Share and Enjoy!
+ *
+ * Originally posted to the Raspberry Pi forums:
+ *  http://www.raspberrypi.org/phpBB3/viewtopic.php?p=162581#p162581
+ *
+ * Compile this and store it somewhere, then kick it off at boot time
+ *    e.g. by putting it in /etc/rc.local and running it in the
+ *    background &
+ *
+ */
+
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+#include <fcntl.h>
+#include <unistd.h>
+
+#include <wiringPi.h>
+#include <softPwm.h>
+
+#define OK_LED  16
+
+int main ()
+{
+  int fd, i ;
+
+  if ((fd = open ("/sys/class/leds/led0/trigger", O_RDWR)) < 0)
+  {
+    fprintf (stderr, "Unable to change LED trigger: %s\n", strerror (errno)) ;
+    return 1 ;
+  }
+
+  write (fd, "none\n", 5) ;
+  close (fd) ;
+
+  if (wiringPiSetupGpio () < 0)
+  {
+    fprintf (stderr, "Unable to setup GPIO: %s\n", strerror (errno)) ;
+    return 1 ;
+  }
+
+  softPwmCreate (OK_LED, 0, 100) ;
+
+  for (;;)
+  {
+    for (i = 0 ; i <= 100 ; ++i)
+    {
+      softPwmWrite (OK_LED, i) ;
+      delay (10) ;
+    }
+    delay (50) ;
+
+    for (i = 100 ; i >= 0 ; --i)
+    {
+      softPwmWrite (OK_LED, i) ;
+      delay (10) ;
+    }
+    delay (10) ;
+  }
+
+  return 0 ;
+}

examples/serialRead.c

@@ -0,0 +1,31 @@
+
+/*
+ * serialRead.c:
+ *	Example program to read bytes from the Serial line
+ *
+ */
+
+#include <stdio.h>
+#include <string.h>
+#include <errno.h>
+
+#include <wiringSerial.h>
+
+int main ()
+{
+  int fd ;
+
+  if ((fd = serialOpen ("/dev/ttyAMA0", 115200)) < 0)
+  {
+    fprintf (stderr, "Unable to open serial device: %s\n", strerror (errno)) ;
+    return 1 ;
+  }
+
+// Loop, getting and printing characters
+
+  for (;;)
+  {
+    putchar (serialGetchar (fd)) ;
+    fflush (stdout) ;
+  }
+}

examples/servo.c

@@ -0,0 +1,33 @@
+
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+
+#include <wiringPi.h>
+#include <softServo.h>
+
+int main ()
+{
+  if (wiringPiSetup () == -1)
+  {
+    fprintf (stdout, "oops: %s\n", strerror (errno)) ;
+    return 1 ;
+  }
+
+  softServoSetup (0, 1, 2, 3, 4, 5, 6, 7) ;
+
+  softServoWrite (0,  0) ;
+/*
+  softServoWrite (1, 1000) ;
+  softServoWrite (2, 1100) ;
+  softServoWrite (3, 1200) ;
+  softServoWrite (4, 1300) ;
+  softServoWrite (5, 1400) ;
+  softServoWrite (6, 1500) ;
+  softServoWrite (7, 2200) ;
+*/
+
+  for (;;)
+    delay (10) ;
+
+}

examples/tone.c

@@ -0,0 +1,37 @@
+
+#include <stdio.h>
+#include <errno.h>
+#include <string.h>
+
+#include <wiringPi.h>
+#include <softTone.h>
+
+#define RANGE		100
+#define	NUM_LEDS	 12
+
+int scale [8] = { 262, 294, 330, 349, 392, 440, 494, 525 } ;
+
+int main ()
+{
+  int i, j ;
+  char buf [80] ;
+
+  if (wiringPiSetup () == -1)
+  {
+    fprintf (stdout, "oops: %s\n", strerror (errno)) ;
+    return 1 ;
+  }
+
+  softToneCreate (3) ;
+
+  for (;;)
+  {
+    for (i = 0 ; i < 8 ; ++i)
+    {
+      printf ("%3d\n", i) ;
+      softToneWrite (3, scale [i]) ;
+      delay (500) ;
+    }
+  }
+
+}