Started following some tutorial on att85 usi. Downloaded example code from make avr book.

Make AVR Examples/Chapter11_Driving-Servo-Motors/servoSundial/_servoClockFunctions.c

@@ -0,0 +1,45 @@
+#include "_servoClockFunctions.h"
+
+// Realtime-clock handling functions
+void initTimer0_Clock(void) {
+                  /* Normal mode, just used for the overflow interrupt */
+  TCCR0B |= (1 << CS00);  /* 8 MHz clock = ~31250 overflows per second */
+  TIMSK0 |= (1 << TOIE0);           /* timer overflow interrupt enable */
+}
+
+void everySecond(void) {
+  seconds++;
+  if (seconds > 59) {
+    seconds = 0;
+    everyMinute();
+  }
+  LED_PORT ^= (1 << LED0);                                    /* blink */
+  printTime(hours, minutes, seconds);                 /* serial output */
+           /* Turn off servo motor after three seconds into new minute */
+  if (seconds == 3) {
+    disableServo();
+  }
+}
+void everyMinute(void) {
+  minutes++;
+  if (minutes > 59) {
+    minutes = 0;
+    everyHour();
+  }
+  // If during business hours, set servo to new minute
+  // Otherwise, don't need to move motor when laser is off
+  if ((hours >= START_TIME) && (hours < STOP_TIME)) {
+    setServoPosition();
+    enableServo();
+    LASER_PORT |= (1 << LASER);               /* make sure laser is on */
+  }
+  else {                                     /* make sure laser is off */
+    LASER_PORT &= ~(1 << LASER);
+  }
+}
+void everyHour(void) {
+  hours++;
+  if (hours > 23) {                       /* loop around at end of day */
+    hours = 0;
+  }
+}