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, 82 insertions, 0 deletions

diff --git a/docs/source/lang/unimplemented/pulsein.rst b/docs/source/lang/unimplemented/pulsein.rst
new file mode 100644
index 0000000..2b52428
--- /dev/null
+++ b/docs/source/lang/unimplemented/pulsein.rst
@@ -0,0 +1,82 @@
+.. _lang-pulsein:
+
+pulseIn()
+=========
+
+Description
+-----------
+
+Reads a pulse (either HIGH or LOW) on a pin. For example, if
+**value** is **HIGH**, **pulseIn()** waits for the pin to go
+**HIGH**, starts timing, then waits for the pin to go **LOW** and
+stops timing. Returns the length of the pulse in microseconds.
+Gives up and returns 0 if no pulse starts within a specified time
+out.
+
+
+
+The timing of this function has been determined empirically and
+will probably show errors in longer pulses. Works on pulses from 10
+microseconds to 3 minutes in length.
+
+
+
+Syntax
+------
+
+pulseIn(pin, value)
+pulseIn(pin, value, timeout)
+
+
+
+Parameters
+----------
+
+pin: the number of the pin on which you want to read the pulse.
+(*int*)
+
+
+
+value: type of pulse to read: either
+`HIGH <http://arduino.cc/en/Reference/Constants>`_ or
+`LOW <http://arduino.cc/en/Reference/Constants>`_. (*int*)
+
+
+
+timeout (optional): the number of microseconds to wait for the
+pulse to start; default is one second (*unsigned long*)
+
+
+
+Returns
+-------
+
+the length of the pulse (in microseconds) or 0 if no pulse started
+before the timeout (*unsigned long*)
+
+
+
+Example
+-------
+
+::
+
+
+
+    int pin = 7;
+    unsigned long duration;
+
+    void setup()
+    {
+      pinMode(pin, INPUT);
+    }
+
+    void loop()
+    {
+      duration = pulseIn(pin, HIGH);
+    }
+
+
+
+
+.. include:: /lang/cc-attribution.txt