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README
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The libopencm3 project aims to create an open-source firmware library for
various ARM Cortex-M3 microcontrollers.
Currently (at least partly) supported microcontrollers:
- ST STM32F1 series
- ST STM32F2 series
- ST STM32F4 series
- NXP LPC1311/13/42/43
The library is written completely from scratch based on the vendor datasheets,
programming manuals, and application notes. The code is meant to be used
with a GCC toolchain for ARM (arm-elf or arm-none-eabi), flashing of the
code to a microcontroller can be done using the OpenOCD ARM JTAG software.
Status and API
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The libopencm3 project is currently work in progress. Not all subsystems
of the microcontrollers are supported, yet.
IMPORTANT: The API of the library is NOT yet considered stable! Please do
not rely on it, yet! Changes to function names, macro names etc.
can happen at any time without prior notice!
Prerequisites
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Building requires python, and a python YAML module. (Some code is generated)
For Ubuntu
$ [sudo] apt-get install python-yaml
For Fedora
$ [sudo] yum install PyYAML
For Windows
Download and install:
msys - sourceforge.net/projects/mingw/files/MSYS/Base/msys-core/msys-1.0.11/MSYS-1.0.11.exe
Python - http://www.python.org/ftp/python/2.7/python-2.7.msi (use installer to get the right registry keys for PyYAML)
PyYAML - http://pyyaml.org/download/pyyaml/PyYAML-3.10.win32-py2.7.exe
arm-none-eabi toolchain - for example this one https://launchpad.net/gcc-arm-embedded
Run msys shell and set the path without standard Windows paths, so Windows programs such as 'find' won't interfere:
export PATH="/c//Python27:/c/ARMToolchain/bin:/usr/local/bin:/usr/bin:/bin"
After that you can navigate to the folder where you've extracted libopencm3 and build it.
Building
--------
$ make
You may want to override the toolchain (e.g., arm-elf or arm-none-eabi):
$ PREFIX=arm-none-eabi make
For a more verbose build you can use
$ make V=1
Example projects
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The library ships with a few small example projects which illustrate how
individual subsystems of the microcontrollers can be configured and used with
libopencm3. The makefiles are generally useable for your own projects with
only minimal changes for the libopencm3 install path (See Installation)
For flashing the 'miniblink' example (after you built libopencm3 and the
examples by typing 'make' at the top-level directory) onto the Olimex
STM32-H103 eval board (ST STM32F1 series microcontroller), you can execute:
$ cd examples/stm32/f1/stm32-h103/miniblink
$ make flash
The Makefiles of the examples are configured to use a certain OpenOCD
flash programmer, you might need to change some of the variables in the
Makefile if you use a different one.
You can also flash manually like this:
$ openocd -f interface/jtagkey-tiny.cfg -f target/stm32f1x.cfg
$ telnet localhost 4444
> reset halt
> flash write_image erase foobar.hex
> reset
Replace the "jtagkey-tiny.cfg" with whatever JTAG device you are using, and/or
replace "stm32f1x.cfg" with your respective config file. Replace "foobar.hex"
with the file name of the image you want to flash.
Installation
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$ make install
This will install the library into /usr/local. (permissions permitting)
If you want to install it elsewhere, use the following syntax:
$ make DESTDIR=/opt/libopencm3 install
If you want to attempt to install into your toolchain, use this:
$ make DETECT_TOOLCHAIN=1 install
Note: If you install this into your toolchain, you don't need to pass
any extra -L or -I flags into your projects. However, this also means
you must NOT pass any -L or -I flags that point into the toolchain. This
_will_ confuse the linker. (ie, for summon-arm-toolchain, do NOT pass
-L/home/user/sat/lib) Common symptoms of confusing
the linker are hard faults caused by branches into arm code.
You can use objdump to check for this in your final elf.
Coding style and development guidelines
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See HACKING.
License
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The libopencm3 code is released under the terms of the GNU Lesser General
Public License (LGPL), version 3 or later.
See COPYING.GPL3 and COPYING.LGPL3 for details.
Mailing lists
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* Developer mailing list (for patches and discussions):
https://lists.sourceforge.net/lists/listinfo/libopencm3-devel
* Commits mailing list (receives one mail per 'git push'):
https://lists.sourceforge.net/lists/listinfo/libopencm3-commits
Website
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http://libopencm3.org
http://sourceforge.net/projects/libopencm3/