This is a minimalistic project aimed to show basic CMake setup steps required for programming of the ESP8266 chip. The core approach used here was initially based on the rzajac assembly.
ESP8266 chip has an Xtensa processor architecture. Xtensa strongly differs from the architectures present in common PC's. It means that compilation of the same C/C++ code would produce absolutely different binaries for your PC and Xtensa. Compilation for the different architecture on the host machine (computer that is used for compilation) is called cross-compilation. For many popular microcontroller architectures, for example ARM processors, required cross-compilation tools can be easily installed using system package manager. However, there is no such case yet for ESP8266 implementation of Xtensa.
One of the strongest cross-compilation toolsets known for the moment is crosstool-NG. This project sopports many architectures including Xtensa, however out of the box ESP8266 support could not be provided by crosstool-NG group because of the flexibility of Xtensa and many variations of it's implementation in different microcontrollers. As a consequence, Max Filippov created a crosstool-NG fork that was especially oriented to the Xtensa chips including ESP8266. However, even the Max Filippov's project is too generic to start with a concrete chip. It contains just a forked crosstool-NG that is a pure GCC-based compiler and does not include any chip specific API-s. The complete toolset for ESP8266 is collected within Paul Sokolovsky's open-esp-sdk project. Clean installation of the open-esp-sdk is the only requirement for HelloESP8266 and this is the point where we start the discussion.
The first step is to clone this project to you local drive:
git clone https://github.com/YKolokoltsev/HelloESP8266.git && cd HelloESP8266
Open-esp-sdk is distributed as a source code and shell be compiled before it's usage. It's compilation can be not a trivial task for different Linux distributions (MacOS and Windows are not considered for the moment). An example of it's installation for Debian/Ubuntu families is present at open-esp-sdk project page. However it may depend on the operating system version. For this reason we support two different scenario of the open-esp-sdk installation. The first one and the most desirable - is the manual compilation of the open-esp-sdk on the host machine. If it was successful, just create a symlink called open-esp-sdk within HelloESP8266 cloned folder that points onto the open-esp-sdk:
ln -s <esp-open-sdk folder> ./esp-open-sdk
NOTE:
As long as esp-open-sdk folder is supposed to be inside of a project tree, in CLion it should de excluded:
project_tree->esp-open-sdk->Mark Directory as->Excluded. This operation will speed-up considerably automatic indexing process during each build.
It is highly useful to build the toolchain within your linux-box. However, sometimes this process is not trivial due to many dependencies that may be absent within your default package meneger (see the first stage of the Docker file provided by Larsks). Therefore it is proposed the Docker script that permits to make a remote compilation within the docker container. To create a corresponding image you can use the following commands:
docker build -t esp-open-sdk docker
docker system prune --force
Creating of a docker image is a two stage process, and it requires at least 6 Gb of available space. The compilation takes a long time.
Than you can link a local HelloESP8266 folder where you have executed all previous commands as docker container volume. In this case it is important not to execute the /bin/bash command within your docker run because this command already exist in the Dockerfile and it is a startup-script.
docker run -it -v `pwd`:/opt/HelloESP8266 esp-open-sdk
cmake -S . -B tmp-build
make -C ./tmp-build/ c_01_blink
After this run the tmp-build folder will be created within your project root. This folder will contain two files: 0x00000.bin and 0x10000.bin. In this case you can be sure that compilation has passed successfully. These binary files are the firmware for the esp8266 board that will blink it's LED. You can upload them manually into the flash memory using esptool.py as it is described here.
CLion: Install Serial Port Monitor plugin to read custom debug messages using os_printf function: File->Settings->Plugins->Browse repositories->Serial; However be sure you turn off serial monitor each time before flash your chip.