Serial communication using Rx and Tx pins

Hi everyone !

First of all, I'm sorry if this question seems a little dumb as I'm a newbie in Arduino but I wanted to know if I can perform serial communications without using the USB port of an arduino card.

I've read that the pin 0 and 1 on an Arduino Uno/Genuino are meant for serial communications but how can you actually wire it to a PC ?

Can you display on the serial monitor a message like Serial.print("hello") using those 2 pins ?

owlowish: Can you display on the serial monitor a message like Serial.print("hello") using those 2 pins ?

http://www.arduino.cc/en/Reference/Serial

https://learn.adafruit.com/adafruit-arduino-lesson-5-the-serial-monitor/overview

You need RS232 level converters to start with. A 5V level at the Arduino will be converted to -12V and a 0V will be translated to 12V. Have a look at e.g. the MAX232.

If you also wire the DTR, you should also be able to upload as well. It might be advisable not to do so, so starting Serial Monitor will not cause the Arduino to reset when using RS232 but will when using USB so you can still upload.

If you have a PC with a serial port you can connect the Rx and Tx and GND pins to it through a MAX232 chip or equivalent.

Without a serial port on the PC you need to use a USB to TTL converter - which is what the regular Arduino USB connection does.

…R

owlowish: how can you actually wire it to a PC ?

You can set it up with level shifters and connect to the serial port - assuming that the PC has one - but I submit the better question is: why would you bother? The USB cable does just fine. Pins 0,1 do just fine talking serial to other things, like another Uno or bluetooth, no messing about with level shifting required. Why, you might even be able to say "Hello world" to your PC via that bluetooth, if you feel the need.

Nick_Pyner: why would you bother? The USB cable does just fine.

Maybe so you can hook up serial monitor without resetting the Arduino ;)

sterretje: Maybe so you can hook up serial monitor without resetting the Arduino ;)

It is hardly difficult to do that if you need to, with USB.

Paul__B: It is hardly difficult to do that if you need to, with USB.

Show me without modifying the board please.

sterretje: Show me without modifying the board please.

That is a nonsense assertion.

The board is designed to be modified.

With a sharp knife, cut the bridge on the "RESET-EN" jumper. |500x375 With care, you can solder a (preferably "mini") two-pin header and use a jumper when you need to program it. Or you may be able to mount a miniature slider or pushbutton.

Even without it is of course, possible to manually reset the board when you see the "Done compiling" message in the blue band on the IDE.


And yes, before someone comments, there is another way. :grinning:

Thanks. Never knew there were the shorted solder pads.