Digital I/O capacity of Arduino Uno

Dear keepers of the Arduino web site,

I humbly ask that you consider the following question.

When comparing board specs here, https://www.arduino.cc/en/Products/Compare

it is apparent that the Micro’s 20 digital I/O pins result from counting the 6 analog pins as digital pins. This is appropriate because the analog pins can be used for digitalWrite, digitalRead, as well as analogRead. The chart says that the Uno provides 14 digital I/O. This does not include the 6 analog pins A0 – A5 which can serve as digital I/O. For the sake of consistency, would it be more accurate to say that the Uno provides 20 digital I/O pins?

The Uno's product description, “It has 14 digital input/output pins (of which 6 can be used as PWM outputs)” might be more accurately written, “It has 20 digital input/output pins (of which 6 can be used as PWM outputs, and 6 can be used as analog input pins). This topic has been discussed before http://forum.arduino.cc/index.php?topic=180144.0 And http://forum.arduino.cc/index.php?topic=128433.0

Thanks for reading.

For the sake of consistency, would it be more accurate to say that the Uno provides 20 digital I/O pins?

No, it would be more accurate to say that the Undo provides up to 20 digital I/O pins, but only if you don't want to use serial I/O or analogue input. But that's a bit too long.

Just my opinion, you understand.

Hi.

I don't agree. Have you ever noticed, even though you've been a registered user for just a week (oops, and two years..), how many users have trouble understanding this ? The Arduino doesn't provide 20 digital I/O pins, plus 6 PWM ("analog") outputs, plus 6 analog inputs. One should read the entire description, not just the part they are looking for, to really know what they have at their hands.

If you click the name of the product you are looking for on that list, you'll be lead to a more detailed description.

The analog input pins are preconfigured to be analog pins. You need to set them to digital if needed. So they actually are analogue inputs with some additional or rather alternative functionality (seen what you can also do with A4 and A5 yet ? ). Therefore the descriptions are accurate.

I think it would be pretty hard to get consensus. The Arduino Micro has 24 digital pins, 12 of which can be used for analog input. Since some of the pins marked with digital numbers can be used as analog and the pins marked as analog can be used as digital, and the ICSP pins are digital pins 14-17, it can be confusing. I have no idea where the number 20 came from.