joaotavora / hello-world-esp32

A CMake-based hello world for ESP-IDF

My CMake template for ESP-IDF (ESP32 in this case)

This was inspired directly from

• https://docs.espressif.com/projects/esp-idf/en/latest/esp32/api-guides/build-system.html#using-esp-idf-in-custom-cmake-projects
• The linked example folder
• My own hello-world-3000 C++ starter template, itself based on ModernCppStarter

From the original README.md, still relevant here:

This example illustrates using ESP-IDF components as libraries in custom CMake projects. The application in this example can run on either host or on an ESP32, and the appropriate libraries are linked to the executable depending on which target is specified. If the target is an ESP32, the libraries created from ESP-IDF components are linked. On the other hand, stub libraries are linked if example is meant to be run on the host to simulate the same application behavior.

Micro tutorial

More or less from 0 on an Arch Linux system. First install the "Espressif IoT Development Framework", aka ESP-IDF from AUR (Archlinux User Repository). You could install it from anywhere else, I suppose.

git clone https://aur.archlinux.org/esp-idf.git
cd esp-idf
makepkg -sir

Now, you must further ask the framework to download and install the toolchain, via pip and a lot of Python I think. It will be installed in your $HOME/.espressif, which is not terrible.

To do that:

/opt/esp-idf/install.sh

Now install some standard tools (here, clang is just so you get the useful clangd LSP tool)

sudo pacman -S cmake ccache clang

On Arch you need to add your user to the uucp group:

sudo usermod -a -G uucp $USER

This should give you permissions to /dev/ttyUSB0 which is where probably your chip is connected to.

Finally, clone this repository

git clone https://github.com/joaotavora/hello-world-esp32

Now pray to your favourite deity:

cd hello-world-esp32
make configure build flash monitor

Didn't work?? Sometimes it seems that explicitly installing some more Python modules is necessary (it shouldn't be, though, maybe something's off with PYTHONPATH).

pip install kconfiglib idf_component_manager esptool

Interesting

At a certain point, after install.sh installs the toolchain, it will ask your to run the export.sh to set IDF_PATH, PATH and a bunch of other variables everytime you want to build something or use your ESP32 chip.

I've so far found this to be unnecessary as long as some of these settings live in the Makefile and you invoke things from there. Your mileage may vary. See the Makefile and the top-level CMakeLists.txt.

Output

Hello world!
This is ESP32 chip with 2 CPU cores, WiFi/BT/BLE, silicon revision 0, 4MB external flash
Restarting in 10 seconds...
Restarting in 9 seconds...
Restarting in 8 seconds...
Restarting in 7 seconds...
Restarting in 6 seconds...
Restarting in 5 seconds...
Restarting in 4 seconds...
Restarting in 3 seconds...
Restarting in 2 seconds...
Restarting in 1 seconds...
Restarting in 0 seconds...

Configuring this Example

To modify the example ESP-IDF project configuration, first create the CMake build directory.

This is done with make configure.

Then execute the menuconfig build target in the build directory:

cmake --build build -- menuconfig