Arduino Reference

Structure

An Arduino program run in two parts:

• void setup()
• void loop()

setup() is preparation, and loop() is execution. In the setup section, always at the top of your program, you would set pinModes, initialize serial communication, etc. The loop section is the code to be executed -- reading inputs, triggering outputs, etc.

• Variable Declaration
• Function Declaration
  • void

Control Structures

• if
• if...else
• for
• switch case
• while
• do... while
• break
• continue
• return

Further Syntax

• ; (semicolon)
• {} (curly braces)
• // (single line comment)
• /* */ (multi-line comment)

Arithmetic Operators

• plus (addition)
• - (subtraction)
• * (multiplication)
• / (division)
• % (modulo)

Comparison Operators

• == (equal to)
• != (not equal to)
• < (less than)
• > (greater than)
• <= (less than or equal to)
• >= (greater than or equal to)

Boolean Operators

• && (and)
• || (or)
• ! (not)

Compound Operators

• ++ (increment)
• -- (decrement)
• += (compound addition)
• -= (compound subtraction)
• *= (compound multiplication)
• /= (compound division)

Variables

Variables are expressions that you can use in programs to store values, such as a sensor reading from an analog pin.

Constants

Constants are particular values with specific meanings.

• HIGH | LOW
• INPUT | OUTPUT

• Integer Constants

Data Types

Variables can have various types, which are described below.

• boolean
• char
• byte
• int
• unsigned int
• long
• unsigned long
• float
• double
• string
• array

Reference

• ASCII chart

Functions

Digital I/O

• pinMode(pin, mode)
• digitalWrite(pin, value)
• int digitalRead(pin)

Analog I/O

• int analogRead(pin)
• analogWrite(pin, value) - PWM

Advanced I/O

• shiftOut(dataPin, clockPin, bitOrder, value)
• unsigned long pulseIn(pin, value)

Time

• unsigned long millis()
• delay(ms)
• delayMicroseconds(us)

Math

• min(x, y)
• max(x, y)
• abs(x)
• constrain(x, a, b)

Random Numbers

• randomSeed(seed)
• long random(max)
• long random(min, max)

Serial Communication

Used for communication between the Arduino board and a computer or other devices. This communication happens via the Arduino board's serial or USB connection and on digital pins 0 (RX) and 1 (TX). Thus, if you use these functions, you cannot also use pins 0 and 1 for digital i/o.

• Serial.begin(speed)
• int Serial.available()
• int Serial.read()
• Serial.flush()
• Serial.print(data)
• Serial.println(data)

Didn't find something? Check the extended reference.