STM32CubeF4 Example Project
===========================

This project showcases a simple example of the new ST Cube HAL API
that will soon replace the ST Standard Peripheral Library.

The most attractive feature of the Cube HAL API is that all source code
is three-clause BSD licensed, with no extra restrictions.
This is in stark contrast to the Standard Peripheral Library's
``MCD-ST Liberty SW License Agreement V2'' which has numerous restrictions.

The aim of the project is an STM32F407VG chip toggling GPIO pins.
LEDs 3 to 6 will toggle on and off each time the ``User'' button is pushed.


The dependencies for the project are:

- make.  Should work with both BSD make and GNU make.

- arm-none-eabi GCC toolchain.  Linaro version is available in
  OpenBSD ports under devel/arm-none-eabi.  Clang has not yet been tested.

- stlink firmware flashing tool from https://github.com/texane/stlink .
  There is an experimental OpenBSD port at https://github.com/chettrick/mystuff .
  It is under devel/stlink.  If you have the Ports Collection already, do:
    $ cd /usr/ports
    $ sudo git clone https://github.com/chettrick/mystuff.git
    $ cd /usr/ports/mystuff/devel/stlink
    $ sudo make
    $ sudo make install

- The STM32F4-Discovery board from ST Microelectronics.
  It can be found at Digikey, Mouser, etc. at a very low cost.

- This project's code (of course).  Note that the Cube HAL API code
  is included in this project in the ``Drivers'' directory.
  The full Cube HAL API code with all Board Support Packages is
  at https://github.com/chettrick/stm32cubef4


To build the project:
    $ mkdir ~/work
    $ cd ~/work
    $ git clone https://github.com/chettrick/stm32cubef4_example.git
    $ cd ~/work/stm32cubef4_example
    $ make


To flash the binary file to the STM32F4-Discovery board:
    Plug a mini-USB cable from the board to a USB port on your computer.
    (No other setup needed, for OpenBSD at least. Have not tested Linux.)

    $ cd ~/work/stm32cubef4_example
    $ make flash

    Push the blue ``User'' button on the board to toggle the LEDs.


The most useful parts of this example project are the Makefiles and
the linker script.  All actual code is verbatim from ST.
The Makefile in the project's root directory first calls out to the
Makefile in the ``Drivers/STM32F4xx_HAL_Driver'' directory to build the
Cube HAL library (named libstm32cubef4.a) and then builds the project,
linking in the HAL library.


The make targets are:

    $ make              # Build library, then project.
    $ make all          # Build library, then project.
    $ make lib          # Build library only.
    $ make prog         # Build project only.
    $ make flash        # Program binary build file into target board.
    $ make clean        # Remove project build files.
    $ make cleanlib     # Remove library build files.
    $ make cleanall     # Remove library and project build files.

The target:

    $ make flash

will build the library, build the project, then flash the binary
into the target board all in one step. Make sure it is plugged in.