Unused i/o pins on Mega 1280/2560---IDE support?

I am working on a project that will need the 15 I/O pins that are not wired up on the production Arduino Mega 1280 or 2560.

I will be making my own boards so i will be able to access them. My question is does the IDE support these pin choices directly e.g.

digitalWrite(65,HIGH) or would I have to use bit level addressing?

In my current sketch if I use a nonsense pin number like 231, or such the compiler, does not complain.....IDE 22, but I can't yet access those extra I/O pins to see if they are responding to my program when valid unused pin numbers are used.


David Garrison

The tables under the covers that Arduino uses to map digitalRead/Write input pin numbers to AVR ports/bits do contain 69 entries, as opposed to 54. So based on simply a quick perusal of the code, it does appear that the software will support all 69 IO points.

Thanks for the response.

Where might I find these tables so I can try to figure out how to assign pin numbers to the presently unused digital ports?

I am using the windows version of the IDE. I took a quick look in the IDE folders and didn't find what I thought I might be looking for!

Best regards and thanks again

David Garrison

On windows, it would show up (for example) in


Thanks Much!

David G.