A0 to Digital Input

Tutorials
1

Hello, Can some show me. If is posible? I want to make A0 Input to A0 digital Input. I want to use it to monitor an ON OFF switch. 1 or 0
Thank You

2

If you check the bit over here, you should be able to find out :slight_smile:
https://docs.particle.io/datasheets/photon-datasheet/#pin-markings

3

I just added an explicit note about this in the docs
https://docs.particle.io/reference/firmware/photon/#digitalread-

1 Like
4

Thank You, Im still trying to figure it out, but no luck yet. I tried this and nothing.

void setup()
{
    Serial.begin(9600);

    pinMode (A0, INPUT); 
} 


int DIGITAL;


void loop()
{

	 DIGITAL = digitalRead(A0);
	 Serial.print(DIGITAL);
	 delay(500); 

}
5

What do you mean with nothing - when I try this it just does what I’d expect:
When connecting A0 to GND I see 0 and when connecting to 3V3 I see 1 what else do you expect?

You could try without serial output like this

void setup()
{
  pinMode (D7, OUTPUT); 
  pinMode (A0, INPUT); 
} 

void loop()
{
  digitalWrite(D7, digitalRead(A0));
}

But if you are using a button you should use INPUT_PULLUP or INPUT_PULLDOWN instead of INPUT.
With my code you’ll notice, that the blue LED is a bit dimmer when A0 is not connected to anything than when A0 is pulled high. This comes from the fact, that a floating pin has no defined state and can report HIGH or LOW unpredictably and also very rapidly changing (hence the dimness).

2 Likes
6

When I do that, I get a reading of 1 all the times. Nothing with 0 reading. I have connected pin A0 to Ground.

7

Then try another pin, you might have fried your pin on some occasion.

Or double check your wiring.

8

I tried pin A1 the same. let me try A2 or A3. I’ll let you know.

9

Can you post a pic where we can see the wiring?

10

@ScruffR I got it working… I guess I fried A0 and A1 )-:hushed: I’m using A2 and is working perfect.
THANK You for your help!

1 Like