Compilers for STM32F303x
I use Eclipse IDE, with the gcc-arm compiler.  They are both free.

Eclipse is an open source IDE, originally created for Java development.  There's a surprisingly large community of developers who keep adding functionality, such as support for embedded processors!

You can debug via the ST-LINK/V2, and you can use the ST Standard Peripheral Library by simply installing a plugin.

There is some learning curve associating with installing and configuring the tools, but once installed I find them quite helpful and easy to use.  In fact, the more I explore Eclipse, the more helpful stuff I find.  And it's hard to beat "free"!

To give you a head start, I suggest setting them up in this order:


Install gcc-arm.
Install gnu make, if you don't already have it.  (type make into a command line to see if the program already exists)
Install the ST-Link utilities.
Install Eclipse for C/C++ developers.
From within Eclipse, install gdb ("gnu Project Debugger") support. Help -&gt; Install.. -&gt; C/C++ GDB Hardware Debugging
Install the GNU ARM Eclipse Plugins, which also integrates the ST Standard Peripheral Library.
Finally, install OpenOCD, which is the last piece of the debugging chain.


Enjoy :)