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Topic: Wake up Leonardo via the watchdog timer (Read 1 time) previous topic - next topic


I am trying to use the SLEEP_MODE_PWR_DOWN sleeping mode with a Leonardo board, and to wake up the board after about 2 min with the watchdog timer.
Since the maximum time of the watchdog is 8 sec, I am calling it 15 times in a for-loop.
However with the code below, the LED toggles every ~5 sec, instead of 2 min!
I have also tried the same code with an arduino Uno and it worked fine.

What do I need to change to make it work with a Leonardo?

Code: [Select]

#include <avr/sleep.h>
#include <avr/power.h>
#include <avr/wdt.h>

#define LED_PIN (13)

volatile int f_wdt=1;

  if(f_wdt == 0){

void enterSleep(void)
  /* Now enter sleep mode. */
  /* The program will continue from here after the WDT timeout*/
  sleep_disable(); /* First thing to do is disable sleep. */
  /* Re-enable the peripherals. */

void setup()
  /*** Setup the WDT ***/
  /* Clear the reset flag. */
  MCUSR &= ~(1<<WDRF);
  /* In order to change WDE or the prescaler, we need to
   * set WDCE (This will allow updates for 4 clock cycles).
  WDTCSR |= (1<<WDCE) | (1<<WDE);

  /* set new watchdog timeout prescaler value */
  WDTCSR = 1<<WDP0 | 1<<WDP3; /* 8.0 seconds */
  /* Enable the WD interrupt (note no reset). */

void loop()
  for (int c = 1; c < 15; c++) {
    if(f_wdt == 1){
      /* Don't forget to clear the flag. */
      f_wdt = 0;
    /* Re-enter sleep mode. */
  /* Toggle the LED */
  digitalWrite(LED_PIN, !digitalRead(LED_PIN));

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