// See https://forum.arduino.cc/index.php?topic=246359.0

#include <avr/wdt.h>
#include <EEPROM.h>

int EEPROM_Address = 0;
//uint8_t signalByte = 1, EEPROM_Contents;

char resetCause = 'p', EEPROM_Contents;

void setup()
{

	wdt_disable();  //disable any previous watchdog

	Serial.begin(57600);

	Serial.println(" ");
	Serial.println("Wecome to WatchDogTest ");
	Serial.println("Watchdog has been reset");

	EEPROM_Contents = EEPROM.read(EEPROM_Address);



	Serial.print("EEPROM Address is: ");
	Serial.print(EEPROM_Address);
	Serial.print("  last reset cause was: ");
	Serial.println(EEPROM_Contents);

	EEPROM.update(EEPROM_Address, 'p');

	/*
	while (true)
	{
		// No code
	}
	*/

	configure_wdt();
	Serial.println(" watch dog now set up");
	
	
	//wdt_enable(WDTO_8S);
	
}
void loop()
{
	resetCause = 'l';

	Serial.print(".");
	delay(500);
	wdt_reset();
}

/* Function to configure the watchdog: let it sleep 8 seconds before firing
   when firing, configure it for interrupts then resetting
	 WDTCSR configuration:
	 WDIE = 1: Interrupt Enable
	 WDE  = 1 :Reset Enable
	 WDP3 = 1 :For 8000ms Time-out
	 WDP2 = 0 :For 8000ms Time-out
	 WDP1 = 0 :For 8000ms Time-out
	 WDP0 = 1 :For 8000ms Time-out
*/
void configure_wdt(void)
{
	cli();			// disable all interrupts
	wdt_reset();	// reset the WDT timer

// First enter Watchdog Configuration mode, then set the bits

	WDTCSR |= (1 << WDCE) | (1 << WDE);
	WDTCSR = (1 << WDIE) | (1 << WDE) | (1 << WDP3) | (0 << WDP2) | (0 << WDP1) | (1 << WDP0);

	sei();		// Re-enable interrupts
}


ISR(WDT_vect) // Watchdog timer interrupt, just EEPROM write our cause
{
	EEPROM.update(EEPROM_Address, resetCause);

}