Merge branch 'wip-family-support'

Merge the long-lived (too long; future changes like these will need to
proceed more incrementally) development branch of libmaple, containing
experimental STM32F2 and STM32F1 value line support, into master.

This required many changes to the structure of the library. The most
important structural reorganizations occurred in:

- 954f9e5: moves public headers to include directories
- 3efa313: uses "series" instead of "family"
- c0d60e3: adds board files to the build system, to make it easier to
  add new boards
- 096d86c: adds build logic for targeting different STM32 series
  (e.g. STM32F1, STM32F2)

This last commit in particular (096d86c) is the basis for the
repartitioning of libmaple into portable sections, which work on all
supported MCUs, and nonportable sections, which are segregated into
separate directories and contain all series-specific code. Moving
existing STM32F1-only code into libmaple/stm32f1 and wirish/stm32f1,
along with adding equivalents under .../stm32f2 directories, was the
principal project of this branch.

Important API changes occur in several places. Existing code is still
expected to work on STM32F1 targets, but there have been many
deprecations. A detailed changelog explaining the situation needs to
be prepared.

F2 and F1 value line support is not complete; the merge is proceeding
prematurely in this respect. We've been getting more libmaple patches
from the community lately, and I'm worried that the merge conflicts
with the old tree structure will become painful to manage.

Conflicts:
	Makefile

Resolved Makefile conflicts manually; this required propagating
-Xlinker usage into support/make/target-config.mk.

Signed-off-by: Marti Bolivar <mbolivar@leaflabs.com>

1 files changed, 63 insertions, 0 deletions

diff --git a/notes/stm32.txt b/notes/stm32.txt
new file mode 100644
index 0000000..106b369
--- /dev/null
+++ b/notes/stm32.txt
@@ -0,0 +1,63 @@
+STM32 platform notes.
+
+Most of this information comes from ST AN3427 (Migrating a
+microcontroller application from STM32F1 to STM32F2 series) and ST
+AN3364 (How to migrate across STM32 series).
+
+The STM32 series of MCUs is divided into series. At time of writing,
+the available series are:
+
+- F1 series (STM32F1)
+- L1 series (STM32L1)
+- F2 series (STM32F2)
+- F4 series (STM32F4)
+
+Some notes on the characteristics of, and differences between, the
+series follow.
+
+F1 Series
+---------
+
+The STM32F1 series is further subdivided into a variety of somewhat
+compatible "lines". Performance, value, and connectivity line MCUs are
+available. (There's also an access line, which is ignored in these
+notes).
+
+At time of writing, libmaple supports medium- and high-density
+performance line MCUs. work to port it to other series is ongoing.
+
+Performance line MCU part numbers begin with STM32F101 or
+STM32F103. The performance line is further subdivided into
+"densities": low, medium, high, and XL.
+
+Value line MCU part numbers begin with STM32F100. Similarly to the
+performance line, the value line is subdivided into medium and high
+densities.
+
+Connectivity line MCU part numbers begin with STM32F105 or
+STM32F107. Mercifully, these are not further subdivided by density.
+
+F2 Series
+---------
+
+A revamp of the F1 series, The F2 series address a number of the
+STM32F1's deficiencies (both silicon bugs and unfortunate design
+decisions), while maintaining a fair amount of software and pin
+compatibility.
+
+The F2 series is most similar to the F1 connectivity line. Like the
+connectivity line, STM32F2s come with a USB on-the-go full speed
+peripheral (like the connectivity line), instead of USB full speed
+device (like the performance line).
+
+F4 Series
+---------
+
+The F4 series MCUs are essentially equivalent to those in the F2
+series, except they have an ARM Cortex M4 core, an FPU, and support a
+higher clock frequencies (168 MHz instead of 120 MHz).
+
+L1 Series
+---------
+
+This series is intended for low-power applications.