Open Source ARM cortex m microcontroller library
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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

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!


 $ 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

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.


 $ 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



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

 * Developer mailing list (for patches and discussions):

 * Commits mailing list (receives one mail per 'git push'):