TX and RX pins Arduino Uno

Using Arduino Programming Questions
#1

Arduino Uno
Can I use Digital Pins 0 and 1 as normal digital inputs if I don’t need to use these pins for serial comms (TX and RX) for my application?

pinMode (0, INPUT);
pinMode (1, INPUT);
pinState = (digitalRead,0);
…

What is it that makes these pins TX/RX are they allocated this purpose only if I use the serial library?

It’s just that I have run out of pins for this application but if I can use these two then all is good

Rich

#2

Can I use Digital Pins 0 and 1 as normal digital inputs if I don't need to use these pins for serial comms (TX and RX) for my application?

Yes, but...

It's just that I have run out of pins for this application but if I can use these two then all is good

You can, but...

The but is that there are resistors associated with these pins, to facilitate their use as serial pins, and these resistors can cause issues with some uses as input and output pins, depending on what the input or output is from or driving.

Try it and see.

Are you using all the analog pins? If not, they can be used as digital pins, too.

#3

No I'm not using the analog pins

So I can just set them with pinMode and use digitalRead same way as the digital pins?

#4

Yes. Use digital pin numbers 14-19 for pins A0-A5 respectively.

#5

thank you

#6

gm1mfn:
Yes. Use digital pin numbers 14-19 for pins A0-A5 respectively.

Better to use the defined constants A0 - A5 since they will map to the correct pins appropriate to the board you're on, rather than hard-coding the assumption that the board is a UNO.

pinMode(A0, OUTPUT);
digitalWrite(A0, HIGH);
 // etc
#7