Arduino Platform

3.0 Programming Environment and Language

The Arduino programming experience is centered around the Arduino IDE and its simplified C++ language.

3.1 The Arduino IDE

The Integrated Development Environment is a simple application for managing, writing, and uploading code. The setup process involves:

Downloading and Installing: Obtaining the correct IDE version for the operating system (Windows, macOS, Linux).
Powering the Board: Connecting the Arduino board to the computer via a USB cable.
Board Selection: Selecting the specific Arduino board model being used from the Tools > Board menu.
Port Selection: Selecting the correct serial port that the board is connected to from the Tools > Serial Port menu.

The IDE toolbar provides essential functions:

Verify: Checks the code for compilation errors.
Upload: Compiles the code and sends it to the Arduino board.
New, Open, Save: Standard file management for sketches.
Serial Monitor: A tool to send and receive serial data between the board and the computer.

3.2 Program Structure: The “Sketch”

An Arduino program is referred to as a sketch. Every sketch has a mandatory two-part structure:

void setup(): This function is called once when the sketch starts (after power-up or reset). It is used to initialize variables, set pin modes, and start using libraries.
void loop(): After setup() completes, the loop() function runs repeatedly. This is where the main logic of the program resides, allowing the program to change and respond to inputs actively.

3.3 Core Language Concepts

The Arduino language is based on C/C++ and includes fundamental programming constructs.

Data Types

Data Type	Description	Storage Size (AVR Boards)	Range (AVR Boards)
boolean	Holds true or false.	1 byte	N/A
byte	Stores an 8-bit unsigned number.	1 byte	0 to 255
char	Stores a character value or small number.	1 byte	-128 to 127
unsigned char	Unsigned version of char.	1 byte	0 to 255
int	Primary data type for numbers.	2 bytes	-32,768 to 32,767
unsigned int	Unsigned version of int.	2 bytes	0 to 65,535
word	A 16-bit unsigned number.	2 bytes	0 to 65,535
long	Extended size variable for integers.	4 bytes	-2,147,483,648 to 2,147,483,647
unsigned long	Unsigned version of long.	4 bytes	0 to 4,294,967,295
float	For floating-point numbers (with decimals).	4 bytes	-3.4028235E+38 to 3.4028235E+38
double	Double-precision floating point. (Same as float on AVR boards).	4 bytes	Same as float
String	An object for manipulating text.	Variable	N/A

Variables and Scope

Local Variables: Declared inside a function or block, only accessible within that scope.
Global Variables: Declared outside of all functions, accessible from anywhere in the program, and persist for the program’s lifetime.

Operators

The language supports a rich set of operators, including:

Control Structures and Loops

Conditional Statements: if, if-else, switch-case allow the program to make decisions and execute different code blocks based on specified conditions.
Loops: for, while, and do-while loops allow for the repeated execution of a block of statements.

Strings

Text can be handled in two ways:

Character Arrays (C-style strings): An array of type char, ending in a null character (\0). This method is memory-efficient but requires manual manipulation.
String Object: A more user-friendly object that provides methods for text manipulation (concat(), replace(), substring(), etc.). This approach is easier to use but consumes more memory, which can be a critical consideration on resource-constrained microcontrollers.