Analog Pin Mapping

Forum 2005-2010 (read only) Hardware Troubleshooting
1

In the doc under Analog Pins, it is stated:

Pin mapping
The Arduino pin numbers corresponding to the analog pins are 14 through 19. Note that these are Arduino pin numbers, and do not correspond to the physical pin numbers on the Atmega chips. The analog pins can be used identically to the digital pins, so for example, the code would look like this to set analog pin 0 to an output, and to set it HIGH:

pinMode(14, OUTPUT);
digitalWrite(14, HIGH);

I am using a Diecimilia board and I don't have a pin series 14 - 19 but I do have a seperate set of pins designates as Analog and numbered 0 - 5. In testing, I can use the analog pins designated as pin 0 - 5 but not pin 14 - 19. I put a pot on analog pin 2 read it just fine using the analogRead() function but I tried doing the same thing designating it as pin 16 and it failed.

Questions:
How does any give piece of code know whether I am talking about digital pin 0 or analog pin 0
What am I missing in the docs?

2

If you do a digitalRead on pin 16, it knows that the (normally) analog pin is to be treated as a digital pin. An analogRead on pin 16 will fail, because there aren't that many analog pins.

3

So if I want to treat these analog pins a GPIO pins I will address them as pins 14 - 19?

Thanks,

Jim

4

Yes.

5

Thanks, PaulS.

Jim