Get started with ESP32 and IDF

After speaking a long about technical specifications and boards components, let's start doing things in order to load firmware in flash memory of microcontrollers!

Now we will install all dependencies and frameworks, in Linux-based and Windows OSs, for ESP32 microcontroller and start programming it.
The framework we chose is the official one, the ESP-IDF, but several other frameworks can be used to programming the ESP32. Among the others the most used are MicroPython and Arduino. Choose the one you prefer!

Linux

Here you can find the official documentation that explains with many more details the installation. For a quick guide read below!

In addition to following packages, a text editor is required: you can use VS Code or emacs or whatever you want!

Open a terminal and type the following commands:

# Install the essential dependencies
sudo apt install cmake wget git python3 python3-pip virtualenv
# Create the workspace folder (if it doesn't exist yet), clone the repository of ESP-IDF version 5.0.4 and install it
mkdir ~/ws/esp
cd ~/ws/esp
git clone --recursive https://github.com/espressif/esp-idf.git -b v5.0.4
cd esp-idf
bash install.sh esp32

# Before programming the ESP32, a set of environment variables need to be defined in the shell environment
#   Let's create an alias to easily load them and invoke it for each terminal you need
cd ~
echo "alias get_idf='. $HOME/ws/esp/esp-idf/export.sh'" >> ~/.bash_aliases
source $HOME/.bash_aliases
get_idf
# The environment is correctly loaded!

It's the moment to create and load on your board the first program that makes the two on-board LEDs blink!
Open a terminal and type:

# First of all load the needed variables by calling the alias
get_idf
cd ~/ws/esp
# Create the project
idf.py create-project blinker
cd blinker/main

Open the blinker.c file inside current folder and copy the content below inside it.
It is the entry-point of your firmware and contains the instruction to perform the actions we want.

#include <stdio.h>

#include <driver/gpio.h>
#include <freertos/FreeRTOS.h>
#include <freertos/task.h>

#define B_LED_PIN GPIO_NUM_32
#define Y_LED_PIN GPIO_NUM_33

void led_blinker_task (void)
{
    esp_rom_gpio_pad_select_gpio(B_LED_PIN);
    gpio_set_direction (B_LED_PIN, GPIO_MODE_OUTPUT);

    esp_rom_gpio_pad_select_gpio(Y_LED_PIN);
    gpio_set_direction (Y_LED_PIN, GPIO_MODE_OUTPUT);

    while (1) {
        gpio_set_level(Y_LED_PIN, 0);
        gpio_set_level(B_LED_PIN, 0);

        gpio_set_level(B_LED_PIN, 1);
        vTaskDelay(pdMS_TO_TICKS(128));
        gpio_set_level(B_LED_PIN, 0);
        vTaskDelay(pdMS_TO_TICKS(128));
        gpio_set_level(B_LED_PIN, 1);
        vTaskDelay(pdMS_TO_TICKS(128));
        gpio_set_level(B_LED_PIN, 0);
        
        gpio_set_level(Y_LED_PIN, 1);
        vTaskDelay(pdMS_TO_TICKS(2000));
    }
}


void app_main(void)
{
    xTaskCreate (&led_blinker_task, "led_blinker_task", 1024, NULL, 2, NULL);
}

Now that everything is ready, you can build and flash the program. As explained in the video at the beginning of this page, you must leave the jumper JP1 opened to drive the serial communication to ESP microcontroller and then you can connect your board to PC.
After the connection, a serial port appears on your file system. Its path can be /dev/ttyUSB0 or /dev/ttyUSB1 or /dev/ttyUSB2 and so on, depending if you already have connected serial devices. In the following commands, the port path is referred with <PORT> string.
Finally you have to put the target MCU in flash mode, so close the jumper JP2 and push the button SW3 to reset it. The microcontroller can be programmed!

To do that, in a terminal with environment variales already loaded, type the following commands:

cd ~/ws/esp/blinker
idf.py -p <PORT> build flash monitor

The above command will build the entire project (build command), will load the firmware into the ESP flash memory (flash command) and will monitor the output produced by the microcontroller and sent via the serial connection (monitor command).
Keep in mind that you can also invoke build, flash, and monitor commands separately.
Type the command idf.py help to get the full list of available commands.

At this point the board need to be resetted to execute the just flashed firmware.
Let's open the jumper JP2 and push the reset button SW3 to see LEDs in action!

Windows

For Windows OS installation, Espressif provides an installer which automatically performs everything.
Firstly download the installer here and launch it.

After the installation, you can open a ESP-IDF prompt by searching for ESP-IDF 5.0.4 CMD entry in the Start menu.
Once launched, a new prompt is executed with the environment already loaded.

If everything has been installed fine, you can create a project. To do that copy the code and flash the ESP32 in the same way explained for the Linux OS using an ESP-IDF command prompt.

To obtain more information about the Windows OS, here you can find the official documentation.