I'm trying to program AtTiny13 using Arduino IDE. I have connected the atTiny to my PC using USBasp programer.

I want to write a simple blink application to test whether it works or not. Which pins should I blink?

2 Answers 2


You'll need an Arduino library that supports that chip, to make it appear in the Tools > Board list. The library docs will tell you which pins then correspond to which Arduino digital I/Os. From that you can decide which pin to attach an LED to (with resistor) and how to edit the blink sketch.

Example: http://www.instructables.com/id/Pimp-Your-Chocolates-with-Arduino-IDE-and-ATtiny13/step2/Program-the-ATtiny13/

  • There's already Attiny13 in the menu. Should I then just use pins 1-8? Commented Jul 1, 2014 at 22:43
  • 1
    You could of course just try using software "pin 1" and seeing if that works... it's likely that this is ATTiny Port B bit 0 (PB0) which appears on physical pin 5 of the 8-pin DIP chip (see atmel.com/images/doc2535.pdf for other packages).
    – gwideman
    Commented Jul 1, 2014 at 22:53
  • 2
    For more insight, look at file pins_arduino.h for the ATTiny13 somewhere within your ...\arduino\hardware\arduino\??? directory. I am assuming that at some point you added the core definition files that included ATTiny13, as I don't have them on my machine. Note that different core definitions could assign the Arduino pins to different physical pins.
    – gwideman
    Commented Jul 1, 2014 at 22:55
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    avrdude -p t13 -t ... should return device signature. See nongnu.org/avr-libc/user-manual/using_avrprog.html and this tutorial looks helpful tho not for t13: ladyada.net/learn/avr/avrdude.html
    – gwideman
    Commented Jul 1, 2014 at 23:21
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    And presumably you have docs: nongnu.org/avrdude/user-manual/avrdude.html, specifically command line flags: nongnu.org/avrdude/user-manual/…
    – gwideman
    Commented Jul 1, 2014 at 23:23

Because pins 0 and 1 (physical 5,6) are PWM's you should keep them for later ... and you still have A3 and A2 for analogWrite so, you should use Pin 2 (Physical 7, next to +5V) like this :

add this in the setup function

pinMode(2, OUTPUT);

And add this in your loop function:


In case you forget

For reference : SparkFun's Help guide

Remember : Physical pin "1", reset, has a dot marked on it.

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