---
title: Entity Title
title_expanded: Less Than or Equal To
categories: [ "Structure" ]
subCategories: [ "Subcategory Name" ]
---
// ARDUINO LANGUAGE REFERENCE TAGS (above)   ►►►►► ALWAYS INCLUDE IN YOUR FILE ◄◄◄◄◄
// title will show up in the Index of all Reference terms
// If the title is an operator write it out in words in title_expanded
// categories: Pick between Structure, Variable or Function
// The subcategory within the ones available in the index ("Digital I/O", "Arithmetic Operators")

// ARDUINO PYGMENTS HIGHLIGHT ATTRIBUTE   ►►►►► ALWAYS INCLUDE IN YOUR FILE ◄◄◄◄◄



// PAGE TITLE
= title



// OVERVIEW SECTION STARTS
[#overview]
--

[float]
=== Description
// Describe what this Reference term does, and what it is used for	►►►►► THIS SECTION IS MANDATORY ◄◄◄◄◄
Writes an analog value (http://arduino.cc/en/Tutorial/PWM[PWM wave]) to a pin. Can be used to light a LED at varying brightnesses or drive a motor at various speeds. After a call to `analogWrite()`, the pin will generate a steady square wave of the specified duty cycle until the next call to `analogWrite()` (or a call to `digitalRead()` or `digitalWrite()` on the same pin). The frequency of the PWM signal on most pins is approximately 490 Hz. On the Uno and similar boards, pins 5 and 6 have a frequency of approximately 980 Hz.
[%hardbreaks]

image::http://arduino.cc/en/uploads/Main/ArduinoUno_R3_Front_450px.jpg[caption="", title="A beautiful Arduino UNO"]
[%hardbreaks]


[float]
=== Syntax
// Enter Reference term syntax, please specify all available parameters  ►►►►► THIS SECTION IS MANDATORY ◄◄◄◄◄
`analogWrite(pin, value)`


[float]
=== Parameters
// List all available parameters, please describe them one by one adding the data type (e.g int, boolean, char, String, float, long, double...)  ►►►►► THIS SECTION IS MANDATORY FOR FUNCTIONS ◄◄◄◄◄
`pin`: the number of the pin to write to. Allowed data types: int. +
`value`: the duty cycle between 0 (always off) and 255 (always on). Allowed data types: int.


[float]
=== Returns
// Enter what the function returns (e.g. HIGH or LOW), if there is no return please write: _Nothing_   ►►►►► THIS SECTION IS MANDATORY FOR FUNCTIONS ◄◄◄◄◄
Nothing

--
// OVERVIEW SECTION ENDS




// HOW TO USE SECTION STARTS
[#howtouse]
--

[float]
=== Example Code
// Describe what the example code is all about and add relevant code   ►►►►► THIS SECTION IS MANDATORY ◄◄◄◄◄
Sets the output to the LED proportional to the value read from the potentiometer.


[source,arduino]
// Add relevant code that exemplify the use of the Reference term,
// Please note that sometimes when copy-pasting code, a few spaces can be added at the beginnng of each line of code.
// If that happens, please remove the extra spaces. Thanks!
----
int ledPin = 9;      // LED connected to digital pin 9
int analogPin = 3;   // potentiometer connected to analog pin 3
int val = 0;         // variable to store the read value

void setup() {
  pinMode(ledPin, OUTPUT);   // sets the pin as output
}

void loop() {
  val = analogRead(analogPin);   // read the input pin
  analogWrite(ledPin, val / 4);  // analogRead values go from 0 to 1023, analogWrite values from 0 to 255
}
----
[%hardbreaks]


[float]
=== Notes and Warnings
// Add useful notes, tips, caveat, known issues, and warnings about this Reference term
This is because of interactions with the `millis()` and `delay()` functions.
[%hardbreaks]
image::http://arduino.cc/en/uploads/Main/ArduinoUno_R3_Front_450px.jpg[caption="", title="A beautiful Arduino UNO"]
[%hardbreaks]

--
// HOW TO USE SECTION ENDS


// SEE ALSO SECTION
[#see_also]
--

[float]
=== See also
// Link relevant content by category, such as other Reference terms (please add the tag #LANGUAGE#),
// definitions: (please add the tag #DEFINITION#), and examples of Projects and Tutorials
// examples: (please add the tag #EXAMPLE#)


[role="language"]
// Whenever you want to link to another Reference term, or more in general to a relative link,
// use the syntax shown below. Please note that the file format is subsituted by  attribute.
// Please note that you always need to replace spaces that you might find in folder/file names with %20
// The entire link to Reference pages must be lower case, regardless of the case of the folders and files in this repository.
// For language tag, items will be automatically generated for any other item of the same subcategory,
// no need to add links to other pages of the same subcategory
// if you don't include this section, a minimal version with only the other pages of the same subcategory will be generated.
* #LANGUAGE# link:../AsciiDoc_Template-Parent_Of_Entities[Parent Of Entities]
* #LANGUAGE# link:../../AsciiDoc_Dictionary/AsciiDoc_Template-Dictionary[AsciiDoc Template Dictionary]

[role="definition"]
// Please note that all external links need to be opened in a new window/tab by adding ^ right before the last square brackets
* #DEFINITION# http://arduino.cc/en/Tutorial/PWM[PWM^]

[role="example"]
// Please note that all external links need to be opened in a new window/tab by adding ^ right before the last square brackets
* #EXAMPLE# http://arduino.cc/en/Tutorial/Blink[Blink^]

--
// SEE ALSO SECTION ENDS