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• void

• digitalRead()

• setup()
• loop()

• pinMode()
• digitalWrite()
• int digitalRead()

• analogReference()
• analogRead()
• analogWrite() - PWM

• shiftOut()
• pulseIn()

• millis()
• micros()
• delay()
• delayMicroseconds()

• min()
• max()
• abs()
• constrain()
• map()
• pow()
• sqrt()

• sin()
• cos()
• tan()

• randomSeed()
• random()

• attachInterrupt()
• detachInterrupt()

• tone()
• noTone()

See the libraries page for interfacing with particular types of hardware.

The Arduino language is based on C/C++ and supports all standard C constructs and some C++ features. It links against AVR Libc and allows the use of any of its functions; see its user manual for details.

Communication

• Serial

• bitRead()
• bitWrite()
• bitSet()
• bitClear()
• bit()

Bits and Bytes

• lowByte()
• highByte()

• word

• word()

• unsigned long micros()

• variable scope

Language Reference (extended)

• char()
• byte()

Looking for something else? Try the list of community-contributed code.

Conversion

• int()
• long()
• float()

• PROGMEM

• Atmega168 pin mapping

• goto

• variable scope

• = (assignment operator)

• = assignment operator

• +  (addition)

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The foundations page has extended descriptions of some hardware and software features.

foundations page has extended descriptions of some hardware and software features.''

Interrupts

• interrupts()
• noInterrupts()

• map(value, fromLow, fromHigh, toLow, toHigh)

• analogReference(type)

• true | false

• analog pins

• floating point constants

• integer constants

• Integer Constants

• floating point contstants

• math.h

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• sqrt(x)

• pow(base, exponent)

• pow(x, n)

Trigonometry

• sin(rad)
• cos(rad)
• tan(rad)

• sin(rad)
• cos(rad)
• tan(rad)

• * dereference operator
• & reference operator

• * dereference operator?
• & reference operator?

• * dereference operator?
• & indirection operator?

Pointer Access Operators

• *dereference operator?
• &indirection operator?

• Atmega168 pin mapping

• Atmega168 pin mapping chart

• analog pins

• int analog pins

• Port Manipulation

• unsigned char

Constants

• HIGH | LOW
• INPUT | OUTPUT

• Integer Constants

Data Types

• void keyword

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In Arduino, the standard program entry point (main) is defined in the core and calls into two functions in a sketch. setup() is called once, then loop() is called repeatedly (until you reset your board).

Arduino Reference (extended)

The Arduino language is based on C/C++ and supports all standard C constructs and some C++ features. It links against AVR Libc and allows the use of any of its functions; see its user manual for details.

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Hardware

• Analog Reference Pin (AREF)

• port manipulation

• Atmega168 pin mapping

• Using AVR libraries

AVR Libraries

Arduino 0008 contains headers for the following libraries:

• Main Library page

• AVR math.h library

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Arduino Reference

Extended Version

The Arduino language is based on C/C++.

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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 pinMode, initialize serial communication, etc. The loop section is the code to be executed -- reading inputs, triggering outputs, etc.

• Variable Declaration
• Function Declaration
  • void keyword

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)
• #define
• #include

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)

Bitwise Operators

• & (bitwise and)
• | (bitwise or)
• ^ (bitwise xor)
• ~ (bitwise not)
• << (bitshift left)
• >> (bitshift right)

Compound Operators

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

• &= (compound bitwise and)
• |= (compound bitwise or)

Variables

Variables are expressions that you can use in programs to store values, like e.g. sensor reading from an analog pin. They can have various types, which are described below.

Data Types

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

Variable Scope & Qualifiers

• variable scope
• static
• volatile
• const
• PROGMEM

Constants

Constants are labels for certain values which are preset in the Arduino compiler. You do not need to define or initialize constants. Arduino includes the following pre-defined constants.

• HIGH | LOW
• INPUT | OUTPUT

• IntegerConstants

Utilities

• cast (cast operator)
• sizeof() (sizeof operator)

Reference

• keywords?
• ASCII chart

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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)

External Interrupts

These functions allow you to trigger a function when the input to a pin changes value.

• attachInterrupt(interrupt, function, mode)
• detachInterrupt(interrupt)

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)

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