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Diffstat (limited to 'docs/source/lang/api/digitalwrite.rst')
| -rw-r--r-- | docs/source/lang/api/digitalwrite.rst | 39 |
1 files changed, 13 insertions, 26 deletions
diff --git a/docs/source/lang/api/digitalwrite.rst b/docs/source/lang/api/digitalwrite.rst index 6124d5f..376cbc3 100644 --- a/docs/source/lang/api/digitalwrite.rst +++ b/docs/source/lang/api/digitalwrite.rst @@ -21,42 +21,26 @@ If the pin has been configured as an ``OUTPUT`` with :ref:`pinMode() <lang-pinmode>` its voltage will be set to the corresponding value: 3.3V for ``HIGH``, and 0V (ground) for ``LOW``. -.. TODO make the following paragraphs true, but refer the reader to -.. INPUT_PULLUP and INPUT_PULLDOWN: - -If the pin is configured as an ``INPUT``, writing a ``HIGH`` value -with ``digitalWrite()`` will enable an internal pullup resistor. -Writing ``LOW`` will disable the pullup. The pullup resistor is enough -to light an LED dimly, so if LEDs appear to work, but very dimly, this -is a likely cause. The remedy is to set the pin to an output with the -:ref:`pinMode() <lang-pinmode>` function. - -.. note:: Pin 13 is harder to use as an input than the other pins - because it has an LED and resistor soldered to it in series. If you - enable its internal pull-up resistor, it will likely hang at around - 1.1V instead of the expected 3.3V because the onboard LED and - series resistor pull the voltage level down. If you must use pin 13 - as a digital input, use an external pull-down resistor. +Because it is soldered to an LED and resistor in series, your board's +:ref:`BOARD_LED_PIN <lang-board-values-led>` will respond slightly +more slowly as an output than the other pins. Example ------- The following example sets pin 13 to ``HIGH``, makes a one-second-long delay, sets the pin back to ``LOW``, and delays again, causing a -blinking pattern:: - - - int ledPin = 13; // LED connected to digital pin 13 +blinking pattern (you could also use :ref:`lang-toggleled`):: void setup() { - pinMode(ledPin, OUTPUT); // sets the digital pin as output + pinMode(BOARD_LED_PIN, OUTPUT); // sets the digital pin as output } void loop() { - digitalWrite(ledPin, HIGH); // sets the LED on - delay(1000); // waits for a second - digitalWrite(ledPin, LOW); // sets the LED off - delay(1000); // waits for a second + 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 } See Also @@ -64,5 +48,8 @@ See Also - :ref:`pinMode <lang-pinmode>` - :ref:`digitalRead <lang-digitalread>` +- :ref:`BOARD_LED_PIN <lang-board-values-led>` +- :ref:`lang-toggleled` +- :ref:`lang-togglepin` -.. include:: cc-attribution.txt +.. include:: /arduino-cc-attribution.txt |