The LEDs namely L, TX and RX on the board. Furthermore, whenever the board is connected, the L LED blinks to the frequency of the delay that I set. [Eg: delay(1000);] If I miss any other LED, do mention their purposes as well! Thank you

1 Answer 1


'L' shows the state of pin13 which is programmable by you for any purpose, whether to read or write to an external device, or just for turn the LED on and off as you have done.

'RX' and 'TX' show the states of the Receive and Transmit pins, respectively, and allow you see when serial communication is taking place.

  • 3
    And lastly there is an 'ON' LED, which shows, that the board is powered.
    – chrisl
    Dec 29, 2018 at 14:20
  • What if I don't use the pin13 and instead use pin12?
    – xplo1t
    Dec 30, 2018 at 18:39
  • 1
    You could wire your own LED & resistor to pin12 or any other pin, to get a similar result. But the 'L' LED is hard-wired to pin 13 so that is the only pin it responds to.
    – JRobert
    Dec 30, 2018 at 19:58

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