Arduino programs can be divided into three main parts:

• Structure.
• Values (Variables and Constants).
• Functions.

Structure:

The basic structure of the Arduino Programming Language is fairly simple and runs in at least two parts, or functions, enclose blocks of statements.

• Where setup() is preparation and loop() is the execution.
• Both functions are required for the program to run.

setup()

• Called once when your program starts.
• Used to initialize pin modes, begin serial,…… etc.
• It must be included in the program even if there are no statements to run.

void setup() {
// put your setup code here, to run once:

}

loop()

•  Loop continuously allowing the program to change, response and controlling the Arduino board.

void loop() {
// put your main code here, to run repeatedly:

}

 pinMode()

• It is used to define the behaviour of PORT pin either INPUT or OUTPUT.

digitalWrite()

• It is used to make PORT pin either logic HIGH(1) or logic LOW(0).

digitalRead()

• It reads digital logic HIGH (1) or logic  LOW(0).

analogRead()

• Atmega328 has 10 bit ADC, therefore it detects Analog voltage and converts it to digital binary no range from 0 to 1023 ( 2^10 ).

analogWrite()

• This function can create an Analog signal, in the form of PWM (Pulse Width Modulation).

Serial.print()

• It is used to send data to outside devices using the serial port. To do so, you need to set up the serial communication baud rate ( data transfer speed in bytes) first (in void setup() as Serial.begin(baud rate)).

delay()

• It is a time delay(wait) in millisecond, i.e. 1000 milliseconds=1 sec.