Arduino Reference Library

196Total topics

114Functions

26Structure

56Variables

Grouped Clickable Topic Index

The index intentionally lists titles only. Click any title to jump directly to the typed details for that topic.

Functions 114

Advanced I/O 6

• noTone()
• pulseIn()
• pulseInLong()
• shiftIn()
• shiftOut()
• tone()

Analog I/O 5

• analogRead()
• analogReadResolution()
• analogReference()
• analogWrite()
• analogWriteResolution()

Bits and Bytes 7

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

Characters 13

• isAlpha()
• isAlphaNumeric()
• isAscii()
• isControl()
• isDigit()
• isGraph()
• isHexadecimalDigit()
• isLowerCase()
• isPrintable()
• isPunct()
• isSpace()
• isUpperCase()
• isWhitespace()

Communication 42

• if (Serial)
• print()
• Serial
• Serial.available()
• Serial.parseFloat()
• Serial.print()
• Serial.println()
• Serial.read()
• Serial.readBytes()
• Serial.readBytesUntil()
• Serial.readStringUntil()
• Serial.write()
• SPI
• SPI.begin()
• SPI.beginTransaction()
• SPI.end()
• SPI.endTransaction()
• SPI.setBitOrder()
• SPI.setClockDivider()
• SPI.setDataMode()
• SPI.transfer()
• SPI.usingInterrupt()
• Stream
• Stream.available()
• Stream.find()
• Stream.findUntil()
• Stream.flush()
• Stream.parseFloat()
• Stream.parseInt()
• Stream.peek()
• Stream.read()
• Stream.readBytes()
• Stream.readBytesUntil()
• Stream.readString()
• Stream.readStringUntil()
• Stream.setTimeout()
• Wire
• Wire.begin()
• Wire.beginTransmission()
• Wire.end()
• Wire.getWireTimeoutFlag()
• Wire.onReceive()

Digital I/O 3

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

External Interrupts 3

• attachInterrupt()
• detachInterrupt()
• digitalPinToInterrupt()

Interrupts 2

• interrupts()
• noInterrupts()

Math 8

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

Random Numbers 2

• random()
• randomSeed()

Time 3

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

Trigonometry 3

• cos()
• sin()
• tan()

USB 11

• Keyboard
• Keyboard Modifiers
• Keyboard.end()
• Keyboard.press()
• Keyboard.print()
• Keyboard.println()
• Keyboard.release()
• Keyboard.releaseAll()
• Mouse
• Mouse.begin()
• Mouse.release()

WiFi 6

• Client
• IPAddress
• Overview
• Server
• UDP
• WiFiClass

Structure 26

Arithmetic Operators 5

• Addition: +
• Division: /
• Multiplication: *
• Remainder: %
• Subtraction: –

Bitwise Operators 4

• Bitshift Left: <<
• Bitwise NOT: ~
• Bitwise OR: |
• Bitwise XOR: ^

Comparison Operators 2

• Less Than or Equal To: <=
• Less Than: <

Compound Operators 5

• Compound Bitwise XOR: ^=
• Compound Multiplication: *=
• Compound Subtraction: -=
• Decrement: —
• Increment: ++

Control Structure 4

• else
• if
• switch…case
• while

Further Syntax 2

• Block Comment: /* */
• Curly Braces: { }

Pointer Access Operators 2

• Dereference Operator: *
• Reference Operator: &

Sketch 2

• loop()
• setup()

Variables 56

Conversion 5

• char()
• long()
• unsigned int()
• unsigned long()
• word()

Data Types 46

• bool
• byte
• char
• float
• int
• long
• short
• size_t
• string
• String
• String append operator
• String comparison operators
• String concatenation operator
• String different-from operator
• String element access operator
• String greater-than operator
• String greater-than-or-equal-to operator
• String less-than operator
• String less-than-or-equal-to operator
• String.c_str()
• String.charAt()
• String.compareTo()
• String.concat()
• String.endsWith()
• String.equals()
• String.equalsIgnoreCase()
• String.getBytes()
• String.indexOf()
• String.lastIndexOf()
• String.length()
• String.remove()
• String.replace()
• String.reserve()
• String.setCharAt()
• String.startsWith()
• String.substring()
• String.toCharArray()
• String.toDouble()
• String.toFloat()
• String.toInt()
• String.toLowerCase()
• String.toUpperCase()
• String.trim()
• unsigned char
• unsigned int
• word

Utilities 2

• PROGMEM
• sizeof()

Variable Scope Qualifiers 3

• const
• scope
• volatile

Detailed Topic Sections

Functions / Advanced I/O

noTone()

Description

Stops a square-wave tone that was previously started with tone(). If no tone is active on that pin, it has no effect.

Syntax / common form

noTone(pin);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Advanced I/O group

Functions / Advanced I/O

pulseIn()

Description

Measures how long a pin stays HIGH or LOW and returns the pulse duration in microseconds.

Syntax / common form

pulseIn(pin, value);
pulseIn(pin, value, timeout);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Advanced I/O group

Functions / Advanced I/O

pulseInLong()

Description

Measures longer pulse durations in microseconds and is used when pulseIn() is not the best fit for a longer signal.

Syntax / common form

pulseInLong(pin, value);
pulseInLong(pin, value, timeout);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Advanced I/O group

Functions / Advanced I/O

shiftIn()

Description

Reads one byte of data one bit at a time from a data pin using a clock pin.

Syntax / common form

byte value = shiftIn(dataPin, clockPin, bitOrder);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Advanced I/O group

Functions / Advanced I/O

shiftOut()

Description

Writes one byte of data one bit at a time to a data pin using a clock pin.

Syntax / common form

shiftOut(dataPin, clockPin, bitOrder, value);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Advanced I/O group

Functions / Advanced I/O

tone()

Description

Generates a square wave on a pin at a specified frequency, often used for buzzers or simple audio output.

Syntax / common form

tone(pin, frequency);
tone(pin, frequency, duration);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Advanced I/O group

Functions / Analog I/O

analogRead()

Description

Reads the value from an analog input pin and converts it to a digital number.

Syntax / common form

int value = analogRead(pin);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Analog I/O group

Functions / Analog I/O

analogReadResolution()

Description

Sets the number of bits used when reading analog values on boards that support adjustable ADC resolution.

Syntax / common form

analogReadResolution(bits);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Analog I/O group

Functions / Analog I/O

analogReference()

Description

Configures the reference voltage used for analog input readings on supported boards.

Syntax / common form

analogReference(type);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Analog I/O group

Functions / Analog I/O

analogWrite()

Description

Writes a PWM value, or a true analog value on supported boards, to an output pin.

Syntax / common form

analogWrite(pin, value);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Analog I/O group

Functions / Analog I/O

analogWriteResolution()

Description

Sets the number of bits used when writing analog or PWM values on boards that support adjustable output resolution.

Syntax / common form

analogWriteResolution(bits);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Analog I/O group

Functions / Bits and Bytes

bit()

Description

Reference entry for bit() in the Arduino Bits and Bytes group.

Syntax / common form

bit(n);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Bits and Bytes group

Functions / Bits and Bytes

bitClear()

Description

Reference entry for bitClear() in the Arduino Bits and Bytes group.

Syntax / common form

bitClear(x, n);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Bits and Bytes group

Functions / Bits and Bytes

bitRead()

Description

Reads the next byte or character from the input buffer.

Syntax / common form

bitRead(x, n);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Bits and Bytes group

Functions / Bits and Bytes

bitSet()

Description

Reference entry for bitSet() in the Arduino Bits and Bytes group.

Syntax / common form

bitSet(x, n);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Bits and Bytes group

Functions / Bits and Bytes

bitWrite()

Description

Writes binary data to the output stream.

Syntax / common form

bitWrite(x, n, b);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Bits and Bytes group

Functions / Bits and Bytes

highByte()

Description

Reference entry for highByte() in the Arduino Bits and Bytes group.

Syntax / common form

highByte(x);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Bits and Bytes group

Functions / Bits and Bytes

lowByte()

Description

Reference entry for lowByte() in the Arduino Bits and Bytes group.

Syntax / common form

lowByte(x);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Bits and Bytes group

Functions / Characters

isAlpha()

Description

Tests whether a character is alphabetic.

Syntax / common form

// Syntax varies by use case for isAlpha()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isAlphaNumeric()

Description

Tests whether a character is a letter or number.

Syntax / common form

// Syntax varies by use case for isAlphaNumeric()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isAscii()

Description

Tests whether a character is within the ASCII range.

Syntax / common form

// Syntax varies by use case for isAscii()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isControl()

Description

Tests whether a character is a control character.

Syntax / common form

// Syntax varies by use case for isControl()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isDigit()

Description

Tests whether a character is a decimal digit.

Syntax / common form

// Syntax varies by use case for isDigit()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isGraph()

Description

Tests whether a character has a visible representation other than a space.

Syntax / common form

// Syntax varies by use case for isGraph()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isHexadecimalDigit()

Description

Tests whether a character is a valid hexadecimal digit.

Syntax / common form

// Syntax varies by use case for isHexadecimalDigit()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isLowerCase()

Description

Tests whether a character is lowercase.

Syntax / common form

// Syntax varies by use case for isLowerCase()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isPrintable()

Description

Tests whether a character is printable.

Syntax / common form

// Syntax varies by use case for isPrintable()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isPunct()

Description

Tests whether a character is punctuation.

Syntax / common form

// Syntax varies by use case for isPunct()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isSpace()

Description

Tests whether a character is a whitespace/spacing character.

Syntax / common form

// Syntax varies by use case for isSpace()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isUpperCase()

Description

Tests whether a character is uppercase.

Syntax / common form

// Syntax varies by use case for isUpperCase()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Characters

isWhitespace()

Description

Tests whether a character is whitespace.

Syntax / common form

// Syntax varies by use case for isWhitespace()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Characters group

Functions / Communication

if (Serial)

Description

Reference entry for if (Serial) in the Arduino Communication group.

Syntax / common form

if (Serial) { /* USB serial is ready */ }

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

print()

Description

Prints data in human-readable text form.

Syntax / common form

// Syntax varies by use case for print()

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Serial

Description

Represents the serial communication interface used to send and receive data over USB or UART, depending on the board.

Syntax / common form

// See methods in the Serial reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Serial.available()

Description

Returns how many bytes are available to read without blocking.

Syntax / common form

int count = Serial.available();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Serial.parseFloat()

Description

Reads characters from a stream and converts them into a floating-point value.

Syntax / common form

float value = Serial.parseFloat();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Serial.print()

Description

Prints data in human-readable text form.

Syntax / common form

Serial.print(value);
Serial.print(value, format);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Serial.println()

Description

Prints data followed by a newline.

Syntax / common form

Serial.println(value);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Serial.read()

Description

Reads the next byte or character from the input buffer.

Syntax / common form

int byteValue = Serial.read();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Serial.readBytes()

Description

Reads multiple bytes into a buffer.

Syntax / common form

Serial.readBytes(buffer, length);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Serial.readBytesUntil()

Description

Reads bytes into a buffer until a terminator character or length limit is reached.

Syntax / common form

Serial.readBytesUntil(character, buffer, length);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Serial.readStringUntil()

Description

Reads characters into a String until a terminator is found or timeout occurs.

Syntax / common form

String s = Serial.readStringUntil(terminator);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Serial.write()

Description

Writes binary data to the output stream.

Syntax / common form

Serial.write(value);
Serial.write(buffer, length);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

SPI

Description

Represents the SPI bus used for fast synchronous communication with peripherals.

Syntax / common form

// See methods in the SPI reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

SPI.begin()

Description

Starts or initializes the interface.

Syntax / common form

SPI.begin();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

SPI.beginTransaction()

Description

Starts an SPI transaction using a selected settings object.

Syntax / common form

SPI.beginTransaction(settings);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

SPI.end()

Description

Stops or shuts down the interface.

Syntax / common form

SPI.end();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

SPI.endTransaction()

Description

Ends the active SPI transaction.

Syntax / common form

SPI.endTransaction();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

SPI.setBitOrder()

Description

Sets whether SPI data is shifted most-significant-bit first or least-significant-bit first.

Syntax / common form

SPI.setBitOrder(order);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

SPI.setClockDivider()

Description

Sets the SPI clock divider on older SPI APIs.

Syntax / common form

SPI.setClockDivider(divider);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

SPI.setDataMode()

Description

Sets the SPI clock polarity and phase mode.

Syntax / common form

SPI.setDataMode(mode);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

SPI.transfer()

Description

Transfers data over SPI while simultaneously receiving data.

Syntax / common form

byte result = SPI.transfer(value);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

SPI.usingInterrupt()

Description

Informs the SPI library that an interrupt may use SPI so transactions can be protected.

Syntax / common form

SPI.usingInterrupt(interruptNumber);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream

Description

Base class for stream-like input/output objects such as Serial, Ethernet clients, and file streams.

Syntax / common form

// See methods in the Stream reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.available()

Description

Returns how many bytes are available to read without blocking.

Syntax / common form

int count = stream.available();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.find()

Description

Searches a stream for a target sequence.

Syntax / common form

bool found = stream.find(target);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.findUntil()

Description

Searches a stream for a target sequence until a terminator is found.

Syntax / common form

bool found = stream.findUntil(target, terminator);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.flush()

Description

Waits for outgoing data to finish or clears/handles buffered data depending on the stream implementation.

Syntax / common form

stream.flush();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.parseFloat()

Description

Reads characters from a stream and converts them into a floating-point value.

Syntax / common form

float value = stream.parseFloat();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.parseInt()

Description

Reads characters from a stream and converts them into an integer value.

Syntax / common form

long value = stream.parseInt();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.peek()

Description

Returns the next byte without removing it from the input buffer.

Syntax / common form

int value = stream.peek();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.read()

Description

Reads the next byte or character from the input buffer.

Syntax / common form

int value = stream.read();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.readBytes()

Description

Reads multiple bytes into a buffer.

Syntax / common form

stream.readBytes(buffer, length);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.readBytesUntil()

Description

Reads bytes into a buffer until a terminator character or length limit is reached.

Syntax / common form

stream.readBytesUntil(character, buffer, length);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.readString()

Description

Reads characters from a stream into a String until timeout.

Syntax / common form

String s = stream.readString();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.readStringUntil()

Description

Reads characters into a String until a terminator is found or timeout occurs.

Syntax / common form

String s = stream.readStringUntil(terminator);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Stream.setTimeout()

Description

Sets how long stream parsing/read functions wait before timing out.

Syntax / common form

stream.setTimeout(milliseconds);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Wire

Description

Arduino I2C/TWI library interface used to communicate with I2C devices.

Syntax / common form

// See methods in the Wire reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Wire.begin()

Description

Starts or initializes the interface.

Syntax / common form

Wire.begin();
Wire.begin(address);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Wire.beginTransmission()

Description

Begins an I2C transmission to a device address.

Syntax / common form

Wire.beginTransmission(address);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Wire.end()

Description

Stops or shuts down the interface.

Syntax / common form

Wire.end();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Wire.getWireTimeoutFlag()

Description

Checks whether the I2C/Wire interface has detected a timeout condition.

Syntax / common form

bool flag = Wire.getWireTimeoutFlag();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Communication

Wire.onReceive()

Description

Registers a handler function that runs when I2C data is received.

Syntax / common form

Wire.onReceive(handler);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to Communication group

Functions / Digital I/O

digitalRead()

Description

Reads whether a digital pin is HIGH or LOW.

Syntax / common form

int state = digitalRead(pin);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Digital I/O group

Functions / Digital I/O

digitalWrite()

Description

Writes HIGH or LOW to a digital output pin, or enables/disables pull-up behavior on an input pin.

Syntax / common form

digitalWrite(pin, value);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Digital I/O group

Functions / Digital I/O

pinMode()

Description

Configures a pin as an input, input with pull-up resistor, or output.

Syntax / common form

pinMode(pin, mode);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Digital I/O group

Functions / External Interrupts

attachInterrupt()

Description

Attaches an interrupt service routine to a hardware interrupt so code can react quickly to pin changes.

Syntax / common form

attachInterrupt(digitalPinToInterrupt(pin), ISR, mode);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to External Interrupts group

Functions / External Interrupts

detachInterrupt()

Description

Removes a previously attached interrupt handler.

Syntax / common form

detachInterrupt(digitalPinToInterrupt(pin));

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to External Interrupts group

Functions / External Interrupts

digitalPinToInterrupt()

Description

Converts a board pin number into the interrupt number expected by attachInterrupt().

Syntax / common form

digitalPinToInterrupt(pin);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to External Interrupts group

Functions / Interrupts

interrupts()

Description

Re-enables interrupts after they were disabled.

Syntax / common form

interrupts();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Interrupts group

Functions / Interrupts

noInterrupts()

Description

Temporarily disables interrupts for timing-sensitive critical sections.

Syntax / common form

noInterrupts();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Interrupts group

Functions / Math

abs()

Description

Returns the absolute value of a number.

Syntax / common form

abs(x);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Math group

Functions / Math

constrain()

Description

Restricts a value so it stays between a lower and upper bound.

Syntax / common form

constrain(x, a, b);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Math group

Functions / Math

map()

Description

Re-maps a number from one numeric range into another.

Syntax / common form

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

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Math group

Functions / Math

max()

Description

Returns the larger of two values.

Syntax / common form

max(x, y);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Math group

Functions / Math

min()

Description

Returns the smaller of two values.

Syntax / common form

min(x, y);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Math group

Functions / Math

pow()

Description

Raises a number to a power.

Syntax / common form

pow(base, exponent);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Math group

Functions / Math

sq()

Description

Returns the square of a value.

Syntax / common form

sq(x);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Math group

Functions / Math

sqrt()

Description

Returns the square root of a value.

Syntax / common form

sqrt(x);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Math group

Functions / Random Numbers

random()

Description

Returns a pseudo-random number in a specified range.

Syntax / common form

random(max);
random(min, max);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Random Numbers group

Functions / Random Numbers

randomSeed()

Description

Initializes the pseudo-random number generator with a seed value.

Syntax / common form

randomSeed(seed);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Random Numbers group

Functions / Time

delay()

Description

Pauses the sketch for a specified number of milliseconds.

Syntax / common form

delay(ms);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Time group

Functions / Time

delayMicroseconds()

Description

Pauses the sketch for a specified number of microseconds.

Syntax / common form

delayMicroseconds(us);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Time group

Functions / Time

micros()

Description

Returns the number of microseconds since the board began running the current program.

Syntax / common form

unsigned long now = micros();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Timing-sensitive functions may be affected by interrupts, board speed, and hardware capabilities.

Back to Time group

Functions / Trigonometry

cos()

Description

Returns the cosine of an angle in radians.

Syntax / common form

cos(rad);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Trigonometry group

Functions / Trigonometry

sin()

Description

Returns the sine of an angle in radians.

Syntax / common form

sin(rad);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Trigonometry group

Functions / Trigonometry

tan()

Description

Returns the tangent of an angle in radians.

Syntax / common form

tan(rad);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Returns a value. The exact type depends on the function.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Trigonometry group

Functions / USB

Keyboard

Description

USB HID keyboard interface for supported boards that can emulate keyboard input.

Syntax / common form

// See methods in the Keyboard reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / USB

Keyboard Modifiers

Description

Reference entry for Keyboard Modifiers in the Arduino USB group.

Syntax / common form

// Syntax varies by use case for Keyboard Modifiers

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / USB

Keyboard.end()

Description

Stops or shuts down the interface.

Syntax / common form

Keyboard.end();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / USB

Keyboard.press()

Description

Reference entry for Keyboard.press() in the Arduino USB group.

Syntax / common form

Keyboard.press(key);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / USB

Keyboard.print()

Description

Prints data in human-readable text form.

Syntax / common form

Keyboard.print(value);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / USB

Keyboard.println()

Description

Prints data followed by a newline.

Syntax / common form

Keyboard.println(value);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / USB

Keyboard.release()

Description

Reference entry for Keyboard.release() in the Arduino USB group.

Syntax / common form

Keyboard.release(key);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / USB

Keyboard.releaseAll()

Description

Reference entry for Keyboard.releaseAll() in the Arduino USB group.

Syntax / common form

Keyboard.releaseAll();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / USB

Mouse

Description

USB HID mouse interface for supported boards that can emulate mouse input.

Syntax / common form

// See methods in the Mouse reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / USB

Mouse.begin()

Description

Starts or initializes the interface.

Syntax / common form

Mouse.begin();

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / USB

Mouse.release()

Description

Reference entry for Mouse.release() in the Arduino USB group.

Syntax / common form

Mouse.release(button);

Parameters / values

Common parameters include pins, values, buffers, counts, strings, addresses, modes, or timeouts depending on the function.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to USB group

Functions / WiFi

Client

Description

Base client networking interface for TCP-style connections.

Syntax / common form

// See methods in the Client reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to WiFi group

Functions / WiFi

IPAddress

Description

Represents an IPv4 address used with networking functions.

Syntax / common form

// See methods in the IPAddress reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to WiFi group

Functions / WiFi

Overview

Description

General overview entry for the WiFi reference group.

Syntax / common form

// See methods in the Overview reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to WiFi group

Functions / WiFi

Server

Description

Base server networking interface for listening for incoming clients.

Syntax / common form

// See methods in the Server reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to WiFi group

Functions / WiFi

UDP

Description

Interface for sending and receiving UDP datagrams.

Syntax / common form

// See methods in the UDP reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to WiFi group

Functions / WiFi

WiFiClass

Description

Main WiFi control class used by WiFi-capable Arduino boards or WiFi libraries.

Syntax / common form

// See methods in the WiFiClass reference group.

Parameters / values

Not a callable function; see related methods or examples for the object/class.

Returns / result

Usually returns nothing unless the specific method is documented otherwise.

Notes

Board/library support can vary. Confirm the target board supports this interface before relying on it.

Back to WiFi group

Structure / Arithmetic Operators

Addition: +

Description

Adds two values.

Syntax / common form

result = a + b;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Arithmetic Operators group

Structure / Arithmetic Operators

Division: /

Description

Divides the left value by the right value.

Syntax / common form

result = a / b;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Arithmetic Operators group

Structure / Arithmetic Operators

Multiplication: *

Description

Multiplies two values.

Syntax / common form

result = a * b;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Arithmetic Operators group

Structure / Arithmetic Operators

Remainder: %

Description

Returns the remainder after integer division.

Syntax / common form

result = a % b;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Arithmetic Operators group

Structure / Arithmetic Operators

Subtraction: –

Description

Subtracts the right value from the left value.

Syntax / common form

result = a - b;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Arithmetic Operators group

Structure / Bitwise Operators

Bitshift Left: <<

Description

Shifts bits left by a selected number of positions.

Syntax / common form

result = a << b;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Bitwise Operators group

Structure / Bitwise Operators

Bitwise NOT: ~

Description

Inverts every bit in a value.

Syntax / common form

result = a ~ b;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Bitwise Operators group

Structure / Bitwise Operators

Bitwise OR: |

Description

Sets each result bit when either input bit is 1.

Syntax / common form

result = a | b;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Bitwise Operators group

Structure / Bitwise Operators

Bitwise XOR: ^

Description

Sets each result bit when the input bits differ.

Syntax / common form

result = a ^ b;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Bitwise Operators group

Structure / Comparison Operators

Less Than or Equal To: <=

Description

Tests whether the left value is less than or equal to the right value.

Syntax / common form

if (a <= b) {
  // code
}

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Comparison Operators group

Structure / Comparison Operators

Less Than: <

Description

Tests whether the left value is less than the right value.

Syntax / common form

if (a < b) {
  // code
}

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Comparison Operators group

Structure / Compound Operators

Compound Bitwise XOR: ^=

Description

Applies bitwise XOR and stores the result back into the variable.

Syntax / common form

x ^= value;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Compound Operators group

Structure / Compound Operators

Compound Multiplication: *=

Description

Multiplies a variable by a value and stores the result back into the variable.

Syntax / common form

x *= value;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Compound Operators group

Structure / Compound Operators

Compound Subtraction: -=

Description

Subtracts a value from a variable and stores the result back into the variable.

Syntax / common form

x -= value;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Compound Operators group

Structure / Compound Operators

Decrement: —

Description

Decreases a variable by one.

Syntax / common form

x--;
--x;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Compound Operators group

Structure / Compound Operators

Increment: ++

Description

Increases a variable by one.

Syntax / common form

x++;
++x;

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Compound Operators group

Structure / Control Structure

else

Description

Runs an alternate block of code when an if condition is false.

Syntax / common form

if (condition) {
  // code
} else {
  // alternate code
}

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Control Structure group

Structure / Control Structure

if

Description

Runs a block of code only when a condition is true.

Syntax / common form

if (condition) {
  // code
}

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Control Structure group

Structure / Control Structure

switch…case

Description

Chooses between multiple code paths based on a matching value.

Syntax / common form

switch (value) {
  case 1:
    // code
    break;
  default:
    // code
    break;
}

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Control Structure group

Structure / Control Structure

while

Description

Repeats a block of code while a condition remains true.

Syntax / common form

while (condition) {
  // repeated code
}

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Control Structure group

Structure / Further Syntax

Block Comment: /* */

Description

Creates a multi-line comment ignored by the compiler.

Syntax / common form

/*
  comment text
*/

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Further Syntax group

Structure / Further Syntax

Curly Braces: { }

Description

Groups statements into a block for functions, conditions, loops, and classes.

Syntax / common form

functionName() {
  // block
}

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Further Syntax group

Structure / Pointer Access Operators

Dereference Operator: *

Description

Accesses the value stored at a pointer address.

Syntax / common form

// Pointer syntax depends on declaration and use context.

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Pointer Access Operators group

Structure / Pointer Access Operators

Reference Operator: &

Description

Gets the memory address of a variable.

Syntax / common form

// Pointer syntax depends on declaration and use context.

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Operator precedence can affect results. Use parentheses when code clarity matters.

Back to Pointer Access Operators group

Structure / Sketch

loop()

Description

Special Arduino function that runs repeatedly after setup() finishes.

Syntax / common form

void loop() {
  // repeats forever
}

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Sketch group

Structure / Sketch

setup()

Description

Special Arduino function that runs once when the sketch starts.

Syntax / common form

void setup() {
  // runs once
}

Parameters / values

Conditions, expressions, operands, or code blocks depending on the language feature.

Returns / result

Not applicable as a standalone return value.

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Sketch group

Variables / Conversion

char()

Description

Casts or converts a value to char.

Syntax / common form

char(value);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Conversion group

Variables / Conversion

long()

Description

Casts or converts a value to long.

Syntax / common form

long(value);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Conversion group

Variables / Conversion

unsigned int()

Description

Casts or converts a value to unsigned int.

Syntax / common form

unsigned int(value);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Conversion group

Variables / Conversion

unsigned long()

Description

Casts or converts a value to unsigned long.

Syntax / common form

unsigned long(value);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Conversion group

Variables / Conversion

word()

Description

Casts or creates a word-sized unsigned value.

Syntax / common form

word(value);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Conversion group

Variables / Data Types

bool

Description

Boolean type that stores true or false.

Syntax / common form

bool value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Data Types group

Variables / Data Types

byte

Description

8-bit unsigned integer type, commonly used for raw byte values.

Syntax / common form

byte value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Exact size can vary by board architecture. Check the board family when range matters.

Back to Data Types group

Variables / Data Types

char

Description

Character type, usually an 8-bit value storing a character or small integer.

Syntax / common form

char value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Data Types group

Variables / Data Types

float

Description

Floating-point numeric type used for decimal values.

Syntax / common form

float value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Data Types group

Variables / Data Types

int

Description

Integer type used for whole numbers. Size depends on the board architecture.

Syntax / common form

int value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Exact size can vary by board architecture. Check the board family when range matters.

Back to Data Types group

Variables / Data Types

long

Description

Larger signed integer type used when int is not large enough.

Syntax / common form

long value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Exact size can vary by board architecture. Check the board family when range matters.

Back to Data Types group

Variables / Data Types

short

Description

Short signed integer type.

Syntax / common form

short value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Exact size can vary by board architecture. Check the board family when range matters.

Back to Data Types group

Variables / Data Types

size_t

Description

Unsigned integer type used to represent sizes and counts.

Syntax / common form

size_t value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Exact size can vary by board architecture. Check the board family when range matters.

Back to Data Types group

Variables / Data Types

string

Description

C-style character array string.

Syntax / common form

string value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Data Types group

Variables / Data Types

String

Description

Arduino String object class for handling text with methods and operators.

Syntax / common form

String value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String append operator

Description

Operator reference for comparing, joining, indexing, or modifying Arduino String objects.

Syntax / common form

String a = "hello";
String b = "world";
// operator syntax depends on operation

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String comparison operators

Description

Operator reference for comparing, joining, indexing, or modifying Arduino String objects.

Syntax / common form

String a = "hello";
String b = "world";
// operator syntax depends on operation

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String concatenation operator

Description

Operator reference for comparing, joining, indexing, or modifying Arduino String objects.

Syntax / common form

String a = "hello";
String b = "world";
// operator syntax depends on operation

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String different-from operator

Description

Operator reference for comparing, joining, indexing, or modifying Arduino String objects.

Syntax / common form

String a = "hello";
String b = "world";
// operator syntax depends on operation

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String element access operator

Description

Operator reference for comparing, joining, indexing, or modifying Arduino String objects.

Syntax / common form

String a = "hello";
String b = "world";
// operator syntax depends on operation

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String greater-than operator

Description

Operator reference for comparing, joining, indexing, or modifying Arduino String objects.

Syntax / common form

String a = "hello";
String b = "world";
// operator syntax depends on operation

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String greater-than-or-equal-to operator

Description

Operator reference for comparing, joining, indexing, or modifying Arduino String objects.

Syntax / common form

String a = "hello";
String b = "world";
// operator syntax depends on operation

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String less-than operator

Description

Operator reference for comparing, joining, indexing, or modifying Arduino String objects.

Syntax / common form

String a = "hello";
String b = "world";
// operator syntax depends on operation

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String less-than-or-equal-to operator

Description

Operator reference for comparing, joining, indexing, or modifying Arduino String objects.

Syntax / common form

String a = "hello";
String b = "world";
// operator syntax depends on operation

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.c_str()

Description

Returns a C-style null-terminated character pointer for the String.

Syntax / common form

const char* p = myString.c_str();

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.charAt()

Description

Returns the character at a specified index.

Syntax / common form

char c = myString.charAt(index);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.compareTo()

Description

Compares two strings and returns ordering information.

Syntax / common form

int result = myString.compareTo(otherString);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.concat()

Description

Appends another value to the end of the String.

Syntax / common form

myString.concat(value);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.endsWith()

Description

Tests whether the String ends with a specified suffix.

Syntax / common form

bool ok = myString.endsWith(suffix);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.equals()

Description

Tests whether the String equals another value exactly.

Syntax / common form

bool ok = myString.equals(otherString);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.equalsIgnoreCase()

Description

Tests equality while ignoring letter case.

Syntax / common form

bool ok = myString.equalsIgnoreCase(otherString);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.getBytes()

Description

Copies String bytes into a byte buffer.

Syntax / common form

myString.getBytes(buffer, bufferSize);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.indexOf()

Description

Finds the first index of a character or substring.

Syntax / common form

int i = myString.indexOf(value);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.lastIndexOf()

Description

Finds the last index of a character or substring.

Syntax / common form

int i = myString.lastIndexOf(value);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.length()

Description

Returns the number of characters in the String.

Syntax / common form

unsigned int n = myString.length();

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.remove()

Description

Removes characters from the String.

Syntax / common form

myString.remove(index);
myString.remove(index, count);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.replace()

Description

Replaces matching characters or substrings.

Syntax / common form

myString.replace(find, replace);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.reserve()

Description

Pre-allocates memory for a String to reduce fragmentation.

Syntax / common form

myString.reserve(size);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.setCharAt()

Description

Changes the character at a selected index.

Syntax / common form

myString.setCharAt(index, character);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.startsWith()

Description

Tests whether the String begins with a specified prefix.

Syntax / common form

bool ok = myString.startsWith(prefix);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.substring()

Description

Extracts part of a String.

Syntax / common form

String part = myString.substring(from);
String part = myString.substring(from, to);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.toCharArray()

Description

Copies the String into a C-style character array.

Syntax / common form

myString.toCharArray(buffer, bufferSize);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.toDouble()

Description

Converts the String to a double value when supported.

Syntax / common form

double value = myString.toDouble();

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.toFloat()

Description

Converts the String to a float value.

Syntax / common form

float value = myString.toFloat();

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.toInt()

Description

Converts the String to an integer value.

Syntax / common form

long value = myString.toInt();

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.toLowerCase()

Description

Converts the String to lowercase in place.

Syntax / common form

myString.toLowerCase();

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

Back to Data Types group

Variables / Data Types

String.toUpperCase()

Description

Converts the String to uppercase in place.

Syntax / common form

myString.toUpperCase();

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

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Variables / Data Types

String.trim()

Description

Removes leading and trailing whitespace from the String.

Syntax / common form

myString.trim();

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

On small-memory boards, heavy String use can fragment memory. For critical projects, consider fixed character buffers.

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Variables / Data Types

unsigned char

Description

8-bit unsigned character/integer type.

Syntax / common form

unsigned char value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Exact size can vary by board architecture. Check the board family when range matters.

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Variables / Data Types

unsigned int

Description

Unsigned integer type that cannot represent negative values.

Syntax / common form

unsigned int value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Exact size can vary by board architecture. Check the board family when range matters.

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Variables / Data Types

word

Description

Unsigned 16-bit value on many Arduino platforms.

Syntax / common form

word value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Exact size can vary by board architecture. Check the board family when range matters.

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Variables / Utilities

PROGMEM

Description

Places constant data into program memory/flash on platforms where this saves RAM.

Syntax / common form

PROGMEM value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

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Variables / Utilities

sizeof()

Description

Returns the number of bytes used by a type or variable.

Syntax / common form

sizeof(variable);
sizeof(type);

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

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Variables / Variable Scope Qualifiers

const

Description

Qualifier that marks a value as read-only after initialization.

Syntax / common form

const value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

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Variables / Variable Scope Qualifiers

scope

Description

Describes where a variable can be seen or used in a program.

Syntax / common form

scope value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

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Variables / Variable Scope Qualifiers

volatile

Description

Qualifier for variables that may change unexpectedly, often inside interrupts.

Syntax / common form

volatile value;

Parameters / values

Variable name, type, value, or object instance depending on the entry.

Returns / result

Not applicable unless the entry is a conversion function or sizeof().

Notes

Use this entry as a quick reference and verify board-specific behavior when needed.

Back to Variable Scope Qualifiers group