Pin13 change when connecting via USB

ouate · September 18, 2020, 1:50pm

When I connect to my arduino (UNO and mega have the same issue) through USB by using the seruial monitor for example, Pin13 change and blink a few time.
The problem is that I'm using this pin for an SPI interface and I don't want it to blink when connecting with USB. Is there a way to stop it from blinking?

PieterP · September 18, 2020, 2:15pm

The blinking shouldn't be an issue for the SPI devices. If you really don't want the LED to blink, you can compile and flash your own version of the bootloader, with the LED flashes disabled:

github.com

Optiboot/optiboot/blob/243ee94ffa9f9d9d1949b0664b18e05918a5c03d/optiboot/bootloaders/optiboot/Makefile#L182


      
          else
          BAUD_RATE_CMD = -DBAUD_RATE=115200
          endif
          
          
HELPTEXT += "Option LED=B3                - set LED pin to particular port/bit\n"
          ifdef LED
          LED_CMD = -DLED=$(LED)
          dummy = FORCE
          endif
          
          
HELPTEXT += "Option LED_START_FLASHES=n   - set number of LED flashes when bootloader starts\n"
          ifdef LED_START_FLASHES
          LED_START_FLASHES_CMD = -DLED_START_FLASHES=$(LED_START_FLASHES)
          dummy = FORCE
          else
          LED_START_FLASHES_CMD = -DLED_START_FLASHES=3
          endif
          
          
HELPTEXT += "Option LED_DATA_FLASH=1      - flash the LED each time data is received.\n"
          ifdef LED_DATA_FLASH
          ifneq ($(LED_DATA_FLASH), 0)

Pieter

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Pin13 change when connecting via USB

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