Arduino Serial Output

Mon 11 March 2024 Arduino arduino / serial port

Overview

• installation: see https://arrizza.com/setup-common

Summary

Prints text to the Arduino Serial Port.

This is a simple Arduino App that blinks the LED and also outputs some data on the serial port. To see that output you need to set up a terminal emulator like Putty or screen and configure it correctly (115200, 8n1).

Configure cmake

See Arduino Setup for details on how to set up CMakeLists.txt for your arduino and port.

Setup

This also sets up the serial port at the 115200 baud rate. A baud is 1 bit per second, so 115200 baud rate is 115,200 bits per second. There are other bits that may get sent for each byte (a start bit, a parity bit and a stop bit).

It also sends a message "setup" to the serial port.

Serial.begin(115200);
Serial.println("setup");

Serial.begin() is a function that sets up the serial port to the given baud rate, in this case 115,200 bps.

The Serial.println() is a function that prints the parameter given to it, in this case the word " setup" and follows it with a newline.

A newline is a carriage return or a linefeed or both, depending on which Operating System you are on. This is equivalent to pressing the Enter key on the keyboard - it puts a new line in the output. It is sometimes abbreviated as "nl" and sometimes it is referred to as "\n" (this is because in many languages "\n" represents a newline sequence).

A carriage return, sometimes abbreviated as "cr", is a single character with hex value 0x0D.

A linefeed, sometimes abbreviated as "lf", is a single character with hex value 0x0A. This is used for most Linux or Unix based systems and for the Arduino.

On Windows, a newline is a two character combination 0x0D 0x0A (carriage return/line feed).

Main Loop

The main loop is similar to "Main Loop" in Arduino LED Blink. It also prints a "1' and "0" to the serial port every second.

Serial.print("1");

Serial.print("0");

The Serial.print() is a function that is identical to the Serial.println() except it does NOT print the newline character. Because of the newline is missing, the "1" and "0" will be side-by-side on the terminal output.

   setup
   101010101010

It will continue writing the "10" sequence until you unplug the USB cable.

Notes

• You must have the terminal emulator (e.g. Putty) configured correctly.

  • for CLion, see "Setup Serial Monitor in CLion" in Arduino Setup
  • for others, see "Setup putty or screen" in Arduino Setup
  • Don't forget. To upload a new version to the Arduino, you have to disconnect the terminal emulator. And that re-plugging in the terminal emulator will reboot your Arduino.

• You should see a "1" when the LED is blinking quickly, and you should see a "0" when the LED is off.

• Try changing the text inside the Serial.println() or Serial.print() statements. You should see whatever you typed in there, showing up on your terminal emulator.

• Try changing the Serial.print() to Serial.println(). You should see a newline after each 1 and 0, something like:

 0
 1
 0
 1
 0
# ... etc ...