Getting started with the ESP32 in Arduino IDE 2 and PlatformIO

Arduino IDE 2

Open File › Preferences (on Mac Arduino IDE › Settings) and paste the address of the Espressif package into “Additional boards manager URLs”:

https://espressif.github.io/arduino-esp32/package_esp32_index.json

Then open the Boards Manager, search for “esp32” and install the package by Espressif Systems: the current version is 3.3.12. Connect the board, choose ESP32 Dev Module and the port from the menu at the top: when the connection is there, the board name appears in bold. The default upload speed is 921600.

The USB driver

Between the USB socket and the ESP32 there is a chip that acts as a serial port. Espressif says the driver is usually already in the operating system and installs itself. If the port doesn't show up, look at the marking on the chip next to the USB socket:

To find the port on Windows open Device Manager, then unplug and plug the board back in: the COM port that disappears and comes back is the board's. On Linux add your user to the dialout group and log in again; on Mac the port is called /dev/cu.…

The first sketch

// First sketch for the ESP32-DevKitC: blinks an LED on GPIO 23 and writes to the Serial Monitor.
// The DevKitC has no LED connected to a pin: LED with a 220 ohm resistor between GPIO 23 and GND.
#include <Arduino.h>

const int PIN_LED = 23;
int conta = 0;

void setup() {
  Serial.begin(115200);          // open the Serial Monitor at the same speed
  pinMode(PIN_LED, OUTPUT);
  Serial.println("Hello, I'm the ESP32!");
}

void loop() {
  digitalWrite(PIN_LED, HIGH);
  delay(500);
  digitalWrite(PIN_LED, LOW);
  delay(500);
  conta++;
  Serial.print("Blinks: ");
  Serial.println(conta);
}

Open the Serial Monitor at 115200: after each reset you will also see the ROM lines, such as rst:0x1 (POWERON_RESET),boot:0x13; boot:0x13 means a normal boot.

The same steps in PlatformIO

Install Visual Studio Code, then from the extensions list the official PlatformIO IDE extension (it already contains everything you need). From PlatformIO Home create a New Project with the board “Espressif ESP32 Dev Module” (esp32dev) and the Arduino framework. The sketch goes in src/main.cpp and must begin with #include <Arduino.h>. This is the configuration file:

[env:esp32dev]
platform = espressif32
board = esp32dev
framework = arduino
monitor_speed = 115200

Many examples out there are written for core 2.x, which has some different functions (for example the PWM ones): if an old sketch doesn't compile, check which version it was written for.

What about the Arduino UNO?

There is nothing to add: the “Arduino AVR Boards” package is already there. Choose Arduino Uno and the port. The UNO does have an LED on pin 13, so the Blink example works as it is (LED_BUILTIN). Many clones use the CH340 chip: if the upload gives the error “can't set com-state”, Arduino recommends installing version 3.7.2022.01 of the driver and blocking automatic updates.

Common mistakes