Goal

• Flash firmware into ESP32

Intro

• Wemos LOLIN D32 PRO
• macOS Mojave 10.14.6

Practice

Setup of Toolchain

• ESP-IDF will use Python
• ESP-IDF essentially contains API (software libraries and source code) for ESP32 and scripts to operate the Toolchain
• If, you need to install pip

  sudo easy_install pip
  

Install pyserial

pip install --user pyserial

Install Cmake & Ninja

• Ninja is a small build system with a focus on speed
• Ninja’s low-level approach makes it perfect for embedding into more featureful build systems
• Ninja is used to build Google Chrome, parts of Android, LLVM, and can be used in many other projects due to CMake’s Ninja backend.
• ccache is optional. However, it is strongly recommended for faster builds

brew install cmake ninja ccache

Get ESP-IDF

• To build applications for the ESP32, you need the software libraries provided by Espressif in ESP-IDF repository

Create local repository directory and clone

• If you execute below commands, ~/esp/esp-idf directory will be created
• You can use any directory, but you will need to adjust paths for the commands respectively
• Keep in mind that ESP-IDF does not support spaces in paths.

mkdir ~/esp
cd ~/esp
git clone --recursive https://github.com/espressif/esp-idf.git

Set up the tools

Execute ESP-IDF Tools installer

cd ~/esp/esp-idf
sh ./install.sh

Set up the environment variables

• The installed tools are not yet added to the PATH environment variable
• To make the tools usable from the command line some environment variables must be set
• You can just execute script which set up variables or add that script in ./profile or .bash_profile

cd ~/esp/esp-idf
sh ./export.sh

Start an nexample project

Copy an example project to ~/esp directory

cd ~/esp
cp -r $IDF_PATH/examples/get-started/hello_world .

Connect Your Device

• Serial ports have the following patterns in their names

OS	Pattern
Windows	likes __COM1__
Linux	starting with __/dev/tty__
macOS	starting with __/dev/cu.__

ls /dev/cu*

Build the project

idf.py build

Flash onto the device

• Flash the binaries that you just built onto your ESP32 board by running
• -b option is optional and default value is 460800
• I set up baud as 115200

The option flash automatically builds and flashes the project, so running idf.py build is not necessary

idf.py -p [PORT_PATH] {-b [BAUD]} flash

Monitor

• Check if “hello_world” is indeed running

  If you want to stop monitoring, type Ctrl + ]

idf.py -p [PORT_PATH] monitor

If the messages were not normal

• Your board is likely using a 26MHz crystal
• Most development board designs use 40MHz, so ESP-IDF uses this frequency as a default value

Menu config

cd ~/esp/hello_world
idf.py menuconfig

Component config -> ESP32-specific

Main XTAL frequency

• Change CONFIG_ESP32_XTAL_FREQ_SEL to 26MHz

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References

• ESPRESSIF Get Started
• Wemos LOLIN D32 Pro
• Ninja