Unused pins

Hi all,

I'm working on a project with an atmega328. I won't be using the ADC's and have no functionality for PC2, PC3, ADC6 and ADC7.

  • Should I put a decoupling cap between AVCC and AGND?
  • Connect AREF to GND?
  • What should I do with the unused pins? Connect to GND?

Thanks,
Jef

Should I put a decoupling cap between AVCC and AGND? Yes. Avcc powers part of the chip.
Connect AREF to GND? No. Leave open.
What should I do with the unused pins? Leave open, turn on internal pullups
pinMode (pin, INPUT_PULLUP);
so the unused pins are not floating around.

Makes sense, didn't think of the internal pullups, good tip :smiley:

CR is a sharpie!

You could tie the unused i/ps to GND

LarryD:
You could tie the unused i/ps to GND

With the caveat that a software mistake can turn the processor into slag.

“Slag”
Yes, always leave them as inputs in this case.