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.. highlight:: cpp
.. _lang-delay:
delay()
=======
Pauses the program for at least a given number of milliseconds. (There
are 1000 milliseconds in a second.)
Library Documentation
---------------------
.. doxygenfunction:: delay
Discussion
----------
While it is easy to create a blinking LED with the ``delay()``
function, and many sketches use short delays for such tasks as switch
debouncing, the use of ``delay()`` in a sketch has significant
drawbacks. No other reading of sensors, mathematical calculations, or
pin manipulation can go on during the delay function, so in effect, it
brings most other activity to a halt. For alternative approaches to
controlling timing see the :ref:`millis() <lang-millis>` function
and the "Blink Without Delay" sketch cited :ref:`below
<lang-delay-seealso>`\ . More knowledgeable programmers usually
avoid the use of ``delay()`` for timing of events longer than tens of
milliseconds, unless the sketch is very simple.
Certain things *do* go on while the ``delay()`` function is
controlling the STM32 chip, however, because the delay function does
not disable interrupts. Serial communication that appears at the RX
pin is recorded, PWM (see :ref:`pwmWrite() <lang-pwmwrite>`\ ) values
and pin states are maintained, and :ref:`interrupts
<lang-attachinterrupt>` will work as they should.
Example
-------
::
void setup() {
// set up the built-in LED pin for output:
pinMode(BOARD_LED_PIN, OUTPUT);
}
void loop() {
digitalWrite(BOARD_LED_PIN, HIGH); // sets the LED on
delay(1000); // waits for a second
digitalWrite(BOARD_LED_PIN, LOW); // sets the LED off
delay(1000); // waits for a second
}
.. _lang-delay-seealso:
See Also
--------
- :ref:`millis() <lang-millis>`
- :ref:`micros() <lang-micros>`
- :ref:`delayMicroseconds() <lang-delayMicroseconds>`
- (Arduino) `Blink Without Delay
<http://arduino.cc/en/Tutorial/BlinkWithoutDelay>`_ example (works
unmodified on Maple)
.. include:: /arduino-cc-attribution.txt
|
