EFM32 Base Project

This base project is designed to provide a quick and platform independent method of building projects for Silicon Labs EFM32 microcontrollers.
Designed and tested on OSX and Debian. Windows might work with cygwig/mingw/gnuwindows tools, but hasn't been attempted.

If you have any issues, suggestions or alterations, feel free to open an issue or a pull request.

Motivation

• Getting started with Microcontrollers is hard (and time consuming)
• Vendor IDEs are ultimately useless when approaching testing and build-automation

This project addresses this by providing a common base for for projects using Silicon Labs EFM32, EZR32 and EFR32 processors.
If you're not into cmake, you might want to check out ARM Mbed Yotta or PlatformIO, both of which offer higher level approaches to embedded setup/development.

Dependencies

• cmake - use brew on osx, or your favourite package manager for linux
• make - should be available by default, otherwise as above
• arm-none-eabi-gcc - Embedded ARM Compiler/Toolchain (https://launchpad.net/gcc-arm-embedded/+download)
• JLink tools - download and install from https://www.segger.com/jlink-software.html

If you're into docker, check out ryankurte/docker-arm-embedded for a containerised toolchain. You will still need JLink tools locally to flash and debug.

Usage

This project can either be used directly or as a submodule in a larger project. Note that submodule use will allow updates to this project for fixes or further device support.
For an example project using this method, see ryankurte/usb-thing.

To use the project directly:

1. Download this repository
2. Change the project name and device in the CMakeLists.txt file
3. Move your source and include files into the source and include directories
4. Add your source files to the CMakeLists.txt file
5. Make something awesome!

To use this project as a submodule:

1. Add the submodule to your (already git controlled) project using:
   git submodule add https://github.com/ryankurte/efm32-base.git
git submodule update
2. Copy the CMakeLists.txt file from this project (efm32-base) to the top level of your project
3. Update the project name and BASE_LOCATION variables in the new CMakeLists.txt
4. Add your source files (and cmake libraries) to the CMakeLists.txt file
5. Make something even more awesome!

Building

Once you have integrated this project with your project, you can build in the standard cmake manner.

1. mkdir build to create the build directory
2. cd build to switch to the build directory
3. cmake .. to configure the build
4. make to execute the build
5. make flash to flash to a device

When configuring the build, you may want to define (either in CMakeLists.txtor using the -D flag) the variables DEVICE, FLASH_ORIGIN, FLASH_LENGTH, RAM_ORIGIN and RAM_LENGTH. If not defined, the build will use the default memory addresses and sizes for the FLASH and RAM regions defined in the Silicon Labs provided linker script for your device (these are usually 0x00000000 and 0x20000000 for flash start and RAM start, respectively).

Debugging

Debugging using a Segger J-Link device (as is present on the Silicon Labs evaluation boards) requires two processes, a GDB server that connects to the target and provides a local interface as well as a GDB instance that connects to this interface. As such, you have to run two terminal sessions and swap between a bit to use this.

1. make debug-server or make ds from the first session to start the debug server and connect to the target
2. make debug or make d from the second session to launch GDB in Terminal User Interface (TUI) mode

You can then use the GDB interface to interact with the running application.

Updating this project

To add devices / update the SDK:

1. Grab the silabs Gecko SDK from somewhere (note that github is no longer supported/updated by silabs).
2. Copy the cmsis, device, drivers, emdrv and emlib folders from the SDK into this repo.
3. Add a test (or tests) to build the new chip families
4. Add hacks to the .cmake files through the repo to fix any new naming inconsistencies (ie. EFM32G210F128 vs. EFR32FG13P231F512GM48 until all the tests build again.
5. Open a PR against the master
6. [Maintainer] Review/Accept PR and Tag the repo with the Gecko SDK version

To add/fix tooling

1. Open an issue with the issue you're having
2. Fork and open a PR referencing the issue
3. [Maintainer] Review/Accept PR

Licensing

Since this is a combination of a number of Silicon Labs (ex. Energy Micro) components, as well as custom additions, licensing is a little interesting. A summary of the licenses involved follows, but I take no responsibility for the accuracy or interpretation of such.

The CMSIS Core falls under a fairly permissive ARM license. This requires that the license requires the copyright and license note to be distributed in the documentation accompanying binary distribution, and that the name ARM LIMITED may not be used to promote any products derived from this without written permission.

The device and emlib components fall under the above ARM license (startup files) as well as a permissive Silicon Labs license. This allows use, alteration and distribution for any purpose provided the origin of the source is not represented, altered versions are plainly marked, and the notice is not removed from the source distribution.

Drivers are covered by the Silabs License Agreement. This is similar to the the license above, however prohibits sublicensing the included code and use of the code on non-silabs devices.

The CMake components of this project are distributed under the MIT license.

What does all this mean?

• Commercial use is not a problem (as you would expect)
• Licenses need to be distributed with device binaries
• Unless you are using the Driver module (ie. USB) you can probably re/sublicense things.
• I have no idea how this interacts with common FOSS licenses :-/