Atmega16 pin not outputting 5V

Thread Starter


Joined May 14, 2020

I'm new to microcontrollers and I'm trying to build this 4x4 LED cube, controlled by an Atmega16:

I've completed the circuit as shown in the tutorial and am testing the output pins before I put together the rest of the cube.
When I set the pins PC0-PC7 to high, I measure 5V at each of the pins except for PC4, which is always 0V. I've taken a look at my soldering and it all seems fine. Is there any obvious reason I'm unable to set PC4 to 5V?

DNA Robotics

Joined Jun 13, 2014
Maybe try a short program that just sets PC4 as output then alternate high & low to blink an LED. If you don’t get 5 volts, check between PC4 and 5 volts to see if it is alternating between ground and open.


Joined Mar 30, 2015
Are microcontrollers sometimes faulty out of the box?
If you bought from a reputable source, it would be rare for it to fail out of the box. Manufacturer screening will find the infant mortality cases, so most parts will last decades before wearing out.

It's more likely that you mishandled the chip and damaged the output. Are you following proper ESD handling techniques?