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, 87 insertions, 0 deletions

diff --git a/docs/source/stm32.rst b/docs/source/stm32.rst
new file mode 100644
index 0000000..d918655
--- /dev/null
+++ b/docs/source/stm32.rst
@@ -0,0 +1,87 @@
+.. _stm32:
+
+Introduction to STM32
+=====================
+
+.. FIXME [v0.0.13] Stub page.
+
+Every Maple board is powered by an STM32 microcontroller (the chip
+which controls all of the pins).  Once you're comfortable using your
+Maple, you'll probably start to get curious about what's going on
+under the hood.  This page is a good place to begin.  It includes an
+overview of the STM32, and helps you make sense of the sometimes
+dizzying array of features, libraries, and documentation that are
+available to you.
+
+The world of the STM32 is a big one, and it's only getting bigger.
+With literally thousands of pages of manuals, datasheets, application
+notes, etc. available for every STM32 microcontroller, and a huge
+variety of categories and subcategories of STM32s available to choose
+from, it's easy to get confused or feel daunted about getting started.
+Don't panic!  We've got `your towel
+<http://en.wikipedia.org/wiki/Know_where_one%27s_towel_is#Knowing_where_one.27s_towel_is>`_
+right here.
+
+.. contents:: Contents
+   :local:
+
+.. _stm32-general:
+
+General Information
+-------------------
+
+- Description of the history and present state of the STM32 line. ARM
+  Cortex-M series etc.
+
+- Introduction and pointers to ARM Cortex-M docs and other good books
+  on the subject.
+
+- Pointers to ST reference manuals. Note that the appropriate
+  reference manual for each board is always documented in that board's
+  hardware page.
+
+.. _stm32-series:
+.. _stm32-series-f1-lines:
+
+STM32 Series
+------------
+
+- Describe families, F1 lines, etc.
+
+- Describe how a product name tells you what you need
+
+ST's Documentation
+------------------
+
+- Classes of documentation: product flyer, datasheet, reference
+  manual, programming manual, application note.
+
+.. _stm32-registers:
+
+Registers and Register Maps
+---------------------------
+
+- General purpose registers vs. peripheral registers.
+
+Perhaps you haven't read it in detail, but maybe you've at least
+thumbed through a few of the sections, trying to gain some
+understanding of what's going on.  If you've done that (and if you
+haven't, just take our word for it), then you know that underneath the
+covers, *everything* is controlled by messing with bits in the
+seemingly endless collections of registers specific to every
+peripheral.  The :ref:`USARTs <usart>` have data registers; (some of
+the) the :ref:`timers <timers>` have capture/compare registers, the
+:ref:`GPIOs <gpio>` have output data registers, etc.
+
+- Peripheral register maps; how they're duplicated for each peripheral
+
+- Portability concerns across series
+
+.. _stm32-libmaple-support:
+
+``libmaple`` STM32 support
+--------------------------
+
+- Descriptions of libmaple's present support for the STM32 line
+  (i.e. currently performance-line only; update when the F2 branch is
+  ready to merge into master etc.).