0.0.10 Documentation checkpoint.

The vast majority of the Maple-specific values have been pulled out of
the higher-level overview pages and replaced with refs into documents
under /docs/source/hardware/.

Much of the work that's left to be done in this regard is labeled with
versioned TODO and FIXME comments.

Suggestions from StephenFromNYC and gbulmer were incorporated from
this forum thread:

      http://forums.leaflabs.com/topic.php?id=703

2 files changed, 159 insertions, 4 deletions

diff --git a/source/libs/servo.rst b/source/libs/servo.rst
index 475f7dd..891f151 100644
--- a/source/libs/servo.rst
+++ b/source/libs/servo.rst
@@ -2,9 +2,8 @@
 
 .. _libs-servo:
 
-=======
- Servo
-=======
+Servo
+=====
 
 .. FIXME [0.0.10] this is out of date
 
@@ -16,7 +15,8 @@ You can use this library in the :ref:`IDE <ide>` by choosing the Servo
 item under the Sketch > Import Library... menu.
 
 If you are using the :ref:`Unix toolchain <unix-toolchain>`, the
-library is located in ``$LIB_MAPLE_HOME/libraries/Servo/``.
+library is located in the ``/libraries/Servo/`` :ref:`libmaple`
+directory.
 
 Servo Class Reference
 ---------------------
@@ -108,3 +108,54 @@ servomotor attached to pin 9, you could write ::
    microseconds.  This will be clamped to lie in the [``min``,
    ``max``\ ] pulse width range set during :ref:`attach()
    <libs-servo-attach>`.
+
+Arduino Compatibility
+---------------------
+
+The Servo class provides a public interface identical to the Arduino
+version's documented functionality (as of Arduino 0021), so in most
+cases, this library will be a drop-in replacement.
+
+However, there are some differences, essentially at the level of
+implementation details.
+
+The major difference is that while the Arduino implementation drives
+the servos with "bit-banged" :ref:`PWM <pwm>`, the Maple
+implementation uses :ref:`timers <timers>` to drive the PWM directly.
+
+Consequently, **the Maple implementation only allows Servo instances
+to** :ref:`attach <libs-servo-attach>` **to pins that support PWM**.
+
+To determine if a pin supports PWM (15 Maple pins do), you can either
+check if "PWM" appears next to its number on the Maple silkscreen, or
+consult the :ref:`pwmWrite() <lang-pwmwrite>` documentation.
+
+RC Servos expect a pulse approximately every 20ms.  In the Maple
+implementation, :ref:`periods <lang-hardwaretimer-setperiod>` are set
+for entire timers, rather than individual channels.  Thus,
+``attach()``\ ing a Servo to a pin can interfere with other pins
+associated with the same timer\ [#fard-servo]_.
+
+Because of this, we recommend connecting multiple servomotors to pins
+which share a timer, in order to keep as many timers free for other
+purposes as possible.  Consult your board's :ref:`Timer Pin Map
+<gpio-pin-maps>` to match up pins and timer channels.
+
+Another difference: although it is not publicly documented to do so,
+the Arduino implementation of `attach()
+<http://arduino.cc/en/Reference/ServoAttach>`_ returns the timer
+channel associated with the newly-attached pin, or 0 on failure (as of
+Arduino 0021).  The Maple implementation returns :ref:`true
+<lang-constants-true>` on success, and :ref:`false
+<lang-constants-false>` on failure (and this is its documented
+behavior).
+
+We currently provide a soft (bit-banged) implementation of the
+:ref:`Wire <libs-wire>` I2C library.
+
+.. rubric:: Footnotes
+
+.. [#fard-servo] The Arduino implementation also captures timer
+   channels in groups as more Servo objects are attached, but the
+   details of which channels have their periods reset when are
+   slightly different.
diff --git a/source/libs/wire.rst b/source/libs/wire.rst
new file mode 100644
index 0000000..2c5bed9
--- /dev/null
+++ b/source/libs/wire.rst
@@ -0,0 +1,104 @@
+.. highlight:: cpp
+
+.. _libs-wire:
+
+Wire
+====
+
+.. TODO [0.1.0] Format this correctly, using Breathe
+
+This page documents the Wire library for the :ref:`i2c` protocol.  You
+can use this library in the :ref:`Maple IDE <ide>` by choosing the
+Wire item under the Sketch > Import Library... menu.
+
+If you are using the :ref:`Unix toolchain <unix-toolchain>`, the
+library is located in the ``/libraries/Wire/`` :ref:`libmaple`
+directory.
+
+Wire Function Reference
+-----------------------
+
+``Wire.begin()``
+    Joins the i2c bus as master, using pin 20 as SDA and pin 21 as SCL
+    (this is compatible with the pin settings on the Arduino Mega).
+
+``Wire.begin(sda, scl)``
+    Like ``Wire.begin()``, but with the given pins as SDA and
+    SCL.
+
+``Wire.beginTransmission(slave_address)``
+    Set up a transmission to a slave device with the given (7-bit)
+    address. Bytes subsequently queued for transmission (using
+    ``Wire.send``) will be sent to ``slave_address`` when ``void
+    Wire.endTransmission()`` is called.
+
+``void Wire.send(byte)``
+    Queues the given byte (``uint8`` or ``int``) to the slave address
+    previously specified by a call to ``Wire.beginTransmission``. At
+    most 32 bytes may be queued in a single transmission.
+
+``Wire.send(string)``
+    Queues a given string (``char*``) for transmission. The characters
+    of the string are individually queued for transmission as
+    bytes. At most 32 bytes may be queued in a single transmission.
+
+``Wire.send(buffer, length)``
+    Queues a byte buffer ``buffer`` (``uint8*`` or ``int*``), with
+    ``length`` elements, for transmission. At most 32 bytes may be
+    queued in a single transmission.
+
+``Wire.endTransmission()``
+    Ends a transmission (begun by ``Wire.beginTransmission(uint8)``),
+    and actually sends the bytes queued by calls to Wire.send.
+
+    The return value is one of the following status codes:
+
+    * ``SUCCESS``: All bytes were transmitted successfully.
+
+    * ``EDATA``: More than 32 bytes were queued for transmission. No
+      bytes are actually sent when this happens.
+
+    * ``ENACKADDR``: Did not receive ACK on transmit of address. No
+      bytes are actually sent when this happens.
+
+    * ``ENACKTRNS``: Did not receive ACK during transmit of data. Some
+      bytes may have been sent when this happens; however, the
+      transmission is aborted after the first byte of data which is
+      not ACKed by the slave device.
+
+    * ``EOTHER``: Other error occurred.
+
+``Wire.requestFrom(address, num_bytes)``
+    Requests ``num_bytes`` bytes from 7-bit slave address
+    address. Returns the actual number of bytes read. These bytes may
+    subsequently be read one at a time using ``Wire.receive()``.
+
+    Note: if ``num_bytes`` exceeds the size of the transmit/receive
+    buffer (currently 32), it will be truncated to 32.
+
+``Wire.receive()``
+    Get and return the next byte read during the previous call to
+    ``Wire.requestFrom(uint8, int)``. You can check how many bytes are
+    left to read using ``uint8 Wire.available()``.
+
+``Wire.available()``
+    Returns the number of bytes which are still available for reading
+    (with ``Wire.receive()``) from the last call to
+    ``Wire.requestFrom(uint8, int)``.
+
+Arduino Compatibility
+---------------------
+
+.. FIXME [0.1.0] Replace this section when i2c Wire wrapper is done
+
+This implementation is synchronous, and thus supports only a subset of
+the full Wire interface (however, the functionality which is supported
+is fully compatible with Arduino). For now, please use the function
+reference which follows when developing projects using our
+implementation.
+
+Please note that the current implementation only supports master mode
+using a bit-banged (software) protocol.  For now, use of the hardware
+:ref:`i2c` peripheral is only available through :ref:`libmaple-i2c`.
+
+