Stop D13 from flashing on reset

Projects Programming
1

Is there a way to stop d13 from switching on and off 3 or 4 times when the chip gets a reset.

Im asking this because i have a relay attached to d13 and on a reset it clicks the relay over when it resets.

Thanks.

2

The only way you'll do that is to burn a custom bootloader to the chip that doesn't flash D13.

3

Will look into a bootloader, or re route the pcb so that the relay goes to a different pin.

Was hoping there would be a simple bit of code to stop it.

Thanks

4

The code is simple, compiling and flashing a variant bootloader is less simple...

[actually there are ways to burn a sketch without the bootloader, using ArduinoISP, I believe - someone
actually done this?]

5

I have altered the circuit so the relay is not on d13, thanks anyway.

6

You could change the fuses so it doesn't run the bootloader. Might make uploading the next sketch harder though.

7

I've been looking into this to.
Not sure what bootloader you are using, but for the optiboot i think it should be possible by defining "LED_START_FLASHES" 0 in the makefile.

In the optiboot.c you'll find this:

#ifndef LED_START_FLASHES
#define LED_START_FLASHES 0
#endif

#if LED_START_FLASHES > 0
  /* Flash onboard LED to signal entering of bootloader */
  flash_led(LED_START_FLASHES * 2);
#endif

#if LED_START_FLASHES > 0
void flash_led(uint8_t count) {
  do {
    TCNT1 = -(F_CPU/(1024*16));
    TIFR1 = _BV(TOV1);
    while(!(TIFR1 & _BV(TOV1)));
#ifdef __AVR_ATmega8__
    LED_PORT ^= _BV(LED);
#else
    LED_PIN |= _BV(LED);
#endif
    watchdogReset();
  } while (--count);
}
#endif