Using ESP-IDF in Custom CMake Projects

This example illustrates using ESP-IDF components as libraries in custom CMake projects. This builds an equivalent application to the hello_world example under examples/get-started/hello_world.

Example Flow

Users looking at this example should focus on the top-level CMakeLists.txt file. This builds an application that can run on targets without relying on the typical ESP-IDF application template. The application itself follows a similar code flow to the aforementioned hello_world example.

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...

Building this Example

To build this example, run the following commands from this directory:

# Create a build directory, and change location to that directory.
mkdir build; cd build
# Invoke CMake, specifying the top-level CMakeLists.txt directory and toolchain file to use. This will generate
# the build system files.
cmake .. -DCMAKE_TOOLCHAIN_FILE=$IDF_PATH/tools/cmake/toolchain-esp32.cmake -DIDF_TARGET=esp32
# Build using the generated build system files.
cmake --build .

Or, execute build.sh script, which contains the same commands mentioned above.

Flashing and Running this Example

To flash this example, we will have to invoke esptool.py and idf_monitor.py manually. While still in the build directory:

Flashing to target

# Write project binaries to flash.
esptool.py --port /dev/ttyUSB0 write_flash @flash_project_args

Running on target

# Monitor the output of the flashed firmware.
idf_monitor.py --port /dev/ttyUSB0 idf_as_lib.elf

Of course, you should replace the specified ports in the commands specified above to the proper one where your device is connected.

There is a discussion on using ESP-IDF in custom CMake projects in the programming guide under API Guides -> Build System (CMake) -> Using ESP-IDF in Custom CMake Projects

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