Simple Watchdog

Author: mikaelpatel

hardware/arduino/avr/cores/arduino/Arduino.h

@@ -30,6 +30,7 @@
 #include <avr/interrupt.h>
 
 #include "binary.h"
+#include "watchdog.h"
 
 #ifdef __cplusplus
 extern "C"{
@@ -73,7 +74,7 @@ void yield(void);
   #define INTERNAL INTERNAL1V1
   #define INTERNAL2V56 9
   #define INTERNAL2V56_EXTCAP 13
-#else  
+#else
 #if defined(__AVR_ATmega1280__) || defined(__AVR_ATmega2560__) || defined(__AVR_ATmega1284__) || defined(__AVR_ATmega1284P__) || defined(__AVR_ATmega644__) || defined(__AVR_ATmega644A__) || defined(__AVR_ATmega644P__) || defined(__AVR_ATmega644PA__)
 #define INTERNAL1V1 2
 #define INTERNAL2V56 3
@@ -171,7 +172,7 @@ extern const uint8_t PROGMEM digital_pin_to_timer_PGM[];
 
 // Get the bit location within the hardware port of the given virtual pin.
 // This comes from the pins_*.c file for the active board configuration.
-// 
+//
 // These perform slightly better as macros compared to inline functions
 //
 #define digitalPinToPort(P) ( pgm_read_byte( digital_pin_to_port_PGM + (P) ) )

hardware/arduino/avr/cores/arduino/main.cpp

@@ -39,14 +39,14 @@ int main(void)
 #if defined(USBCON)
 	USBDevice.attach();
 #endif
-	
+
 	setup();
-    
+
 	for (;;) {
 		loop();
 		if (serialEventRun) serialEventRun();
+		watchdogReset();
 	}
-        
+
 	return 0;
 }
-

hardware/arduino/avr/cores/arduino/watchdog.c

@@ -0,0 +1,38 @@
+#include <Arduino.h>
+
+#define RESET_VECTOR ((void(*)()) 0)
+#define DEFAULT_TIMEOUT 5000
+#define DEFAULT_ONTIMEOUT RESET_VECTOR
+
+static volatile uint16_t ticks = DEFAULT_TIMEOUT;
+static volatile uint16_t timeout = DEFAULT_TIMEOUT;
+static void (*onTimeout)() = DEFAULT_ONTIMEOUT;
+
+void watchdogTimeout(uint16_t ms)
+{
+  noInterrupts();
+  timeout = ms;
+  ticks = ms;
+  interrupts();
+}
+
+void watchdogOnTimeout(void (*function)())
+{
+  noInterrupts();
+  onTimeout = function;
+  interrupts();
+}
+
+void watchdogReset()
+{
+  noInterrupts();
+  ticks = timeout;
+  interrupts();
+}
+
+void watchdogTick()
+{
+  if (--ticks) return;
+  onTimeout();
+  RESET_VECTOR();
+}

hardware/arduino/avr/cores/arduino/watchdog.h

@@ -0,0 +1,16 @@
+#ifndef watchdog_h
+#define watchdog_h
+
+#ifdef __cplusplus
+extern "C"{
+#endif
+
+void watchdogTimeout(uint16_t ms);
+void watchdogOnTimeout(void (*function)());
+void watchdogReset();
+void watchdogTick();
+
+#ifdef __cplusplus
+} // extern "C"
+#endif
+#endif

hardware/arduino/avr/cores/arduino/wiring.c

@@ -21,6 +21,7 @@
 */
 
 #include "wiring_private.h"
+#include "watchdog.h"
 
 // the prescaler is set so that timer0 ticks every 64 clock cycles, and the
 // the overflow handler is called every 256 ticks.
@@ -60,6 +61,7 @@ ISR(TIMER0_OVF_vect)
 	timer0_fract = f;
 	timer0_millis = m;
 	timer0_overflow_count++;
+	watchdogTick();
 }
 
 unsigned long millis()
@@ -79,7 +81,7 @@ unsigned long millis()
 unsigned long micros() {
 	unsigned long m;
 	uint8_t oldSREG = SREG, t;
-	
+
 	cli();
 	m = timer0_overflow_count;
 #if defined(TCNT0)
@@ -99,7 +101,7 @@ unsigned long micros() {
 #endif
 
 	SREG = oldSREG;
-	
+
 	return ((m << 8) + t) * (64 / clockCyclesPerMicrosecond());
 }
 
@@ -226,7 +228,7 @@ void delayMicroseconds(unsigned int us)
 	// per iteration, so execute it us/4 times
 	// us is at least 4, divided by 4 gives us 1 (no zero delay bug)
 	us >>= 2; // us div 4, = 4 cycles
-	
+
 
 #endif
 
@@ -243,7 +245,7 @@ void init()
 	// this needs to be called before setup() or some functions won't
 	// work there
 	sei();
-	
+
 	// on the ATmega168, timer 0 is also used for fast hardware pwm
 	// (using phase-correct PWM would mean that timer 0 overflowed half as often
 	// resulting in different millis() behavior on the ATmega8 and ATmega168)
@@ -333,7 +335,7 @@ void init()
 	sbi(TCCR4B, CS42);		// set timer4 prescale factor to 64
 	sbi(TCCR4B, CS41);
 	sbi(TCCR4B, CS40);
-	sbi(TCCR4D, WGM40);		// put timer 4 in phase- and frequency-correct PWM mode	
+	sbi(TCCR4D, WGM40);		// put timer 4 in phase- and frequency-correct PWM mode
 	sbi(TCCR4A, PWM4A);		// enable PWM mode for comparator OCR4A
 	sbi(TCCR4C, PWM4D);		// enable PWM mode for comparator OCR4D
 #else /* beginning of timer4 block for ATMEGA1280 and ATMEGA2560 */
@@ -342,7 +344,7 @@ void init()
 	sbi(TCCR4B, CS40);
 	sbi(TCCR4A, WGM40);		// put timer 4 in 8-bit phase correct pwm mode
 #endif
-#endif /* end timer4 block for ATMEGA1280/2560 and similar */	
+#endif /* end timer4 block for ATMEGA1280/2560 and similar */
 
 #if defined(TCCR5B) && defined(CS51) && defined(WGM50)
 	sbi(TCCR5B, CS51);		// set timer 5 prescale factor to 64