ESP32

The original, and still the only one that speaks classic Bluetooth serial.

Before you plan anything

No native USB.

Every board carries a separate USB-to-serial chip, which is why you may need a CP210x or CH340 driver before the port even appears.

Wi-Fi 4BLE 4.2Classic BTNo Zigbee or ThreadNo native USBDAC outTouch, 10 pinsPSRAM optionalTwo coresNo MIPI display

Xtensa LX6 · 2 × 240 MHz

ESP32 board photo

We stock

DOIT ESP32 DevKit v1

Cheap, everywhere, and the board most internet tutorials assume. Good first board, poor last one.

See it in the shop →

The pins that matter

Not all forty-odd of them. The five rows that decide whether your wiring works.

Default I2CSDA 21 · SCL 22What the Arduino core uses unless you pass your own pins to Wire.begin().

On-board LEDGPIO 2On most DevKit v1 boards. Some clones use GPIO 5 instead.

Never useGPIO 6–11Wired to the flash chip. Touching them stops the board booting.

Strapping pinsGPIO 0, 2, 5, 12, 15Read at boot. A pull-down on the wrong one leaves you in download mode, and 0, 5 and 15 emit a PWM burst on the way up.

Input onlyGPIO 34–39No output, and no internal pull-up either, so buttons here need a real resistor.

Pinout diagram — DOIT ESP32 DevKit v1

Board settings, all three toolchains

Get one of these wrong and nothing else on the site will work.

Arduino IDEC++Tools → BoardESP32 Dev Module

Also set Upload Speed to 115200 if uploads fail on a long cable.

MicroPythonPython + ThonnyfirmwareESP32_GENERIC-20260201-v1.25.bin

Hold BOOT while the flash starts, or esptool will not find the chip.

PlatformIObuild systemplatformio.iniboard = esp32dev

The most widely tested target in PlatformIO. Nothing special needed.

What catches people out on this chip

These are the support emails. They exist nowhere else on the site because they are true of nothing else.

ADC2 stops working the moment Wi-Fi turns on

The second ADC block shares hardware with the radio. Any analog pin on ADC2 returns garbage while Wi-Fi is up. Move the sensor to an ADC1 pin — this is the single most common “my sensor broke when I added Wi-Fi” report.

GPIO 6 to 11 are not free pins

They are the flash bus. Headers on some clone boards expose them anyway, which is a trap, not a feature.

Input-only pins have no pull-ups

GPIO 34 to 39 accept INPUT_PULLUP in code and silently do nothing with it. A button on those pins needs an external resistor.

Brownouts on USB power

Wi-Fi transmit bursts pull well over 300 mA. A thin cable or an unpowered hub causes reboots that look exactly like a code crash.

News about this chip

2026-08-01MicroPython 1.25 firmware for all five chipsFresh .bin files, and the C6 build finally exposes the Wi-Fi 6 flags.

Guides for this chip

78 of 81 apply

Written once for the whole family. Opening one from here fixes the pins to this chip and the code to your language.

Modules that work with the ESP32

All 47 documented modules work with it. It is the only chip here that can also do classic Bluetooth serial, so the Bluetooth audio and SPP examples are written against this one.

Browse the module index →