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authorPerry Hung <iperry@gmail.com>2011-01-24 23:23:29 -0500
committerPerry Hung <iperry@gmail.com>2011-01-24 23:23:29 -0500
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+.. highlight:: cpp
+
+.. _lang-pwmwrite:
+
+pwmWrite()
+==========
+
+Writes a :ref:`PWM wave <pwm>` to a pin. You can use this to make an
+LED get brighter or dimmer, control a servomotor, etc. After a call to
+pwmWrite(), the pin will output a steady square wave with the given
+duty cycle. You can change the duty cycle later by calling pwmWrite()
+again with the same pin and a different duty.
+
+On the Maple, the pins which support PWM are: 0, 1, 2, 3, 5, 6, 7, 8,
+9, 11, 12, 14, 24, 27, and 28.
+
+The Arduino function :ref:`analogWrite() <lang-analogwrite>` is an
+alias for ``pwmWrite()``, but it is badly named, and its use is
+discouraged.
+
+.. contents:: Contents
+ :local:
+
+Library Documentation
+---------------------
+
+.. doxygenfunction:: pwmWrite
+
+Example
+-------
+
+Sets the output to the LED proportional to the value read from the
+potentiometer::
+
+ int analogPin = 3; // potentiometer connected to analog pin 3
+ int val = 0; // variable to store the read value
+
+ void setup() {
+ pinMode(BOARD_LED_PIN, OUTPUT); // sets the LED pin as output
+
+ pinMode(analogPin, PWM); // sets the potentiometer pin as PWM
+ // output
+ }
+
+ void loop() {
+ val = analogRead(analogPin); // read the input pin
+
+ analogWrite(BOARD_LED_PIN, val / 16); // analogRead values go from 0
+ // to 4095, analogWrite values
+ // from 0 to 65535
+ }
+
+See Also
+--------
+
+- :ref:`Maple PWM tutorial <pwm>`