merge libmaple docs ("leaflabs-docs") into ./docs

In the past, libample documentation was forked out of this repository
because the documentation had increased in scope. For the librambutan,
and the rambutan project in general, we will try to keep documentation
closer to the source code, so the librambutan-specific documentation
should live here. Other sections of leaflabs-docs will be culled in a
following commit.

This merge attempts to maintain history by using a subtree strategy.
Followed directions at:

    http://nuclearsquid.com/writings/subtree-merging-and-you/

Full history for files should be accessible using the "--follow" flag to
git log, eg:

    git log --follow docs/source/adc.rst

It should be possible to pull patches from leaflabs-docs with:

    git pull -s subtree leaflabs-docs master

... at least until the docs in this repository diverge significantly.

1 files changed, 56 insertions, 0 deletions

diff --git a/docs/source/lang/api/digitalwrite.rst b/docs/source/lang/api/digitalwrite.rst
new file mode 100644
index 0000000..bae8db9
--- /dev/null
+++ b/docs/source/lang/api/digitalwrite.rst
@@ -0,0 +1,56 @@
+.. highlight:: cpp
+
+.. _lang-digitalwrite:
+
+digitalWrite()
+==============
+
+Write a :ref:`HIGH <lang-constants-high>` or a :ref:`LOW
+<lang-constants-low>` value to a pin configured as :ref:`OUTPUT
+<lang-constants-output>`.
+
+Library Documentation
+---------------------
+
+.. doxygenfunction:: digitalWrite
+
+Discussion
+----------
+
+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``.
+
+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 the built-in LED pin to ``HIGH``, makes a
+one-second-long delay, sets the pin back to ``LOW``, and delays again,
+causing a blinking pattern (you could also use
+:ref:`lang-toggleled`)::
+
+    void setup() {
+      pinMode(BOARD_LED_PIN, OUTPUT);      // sets the digital pin as 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
+    }
+
+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:: /arduino-cc-attribution.txt