Microcontroller

ESP32-WROOM-32E

Espressif's WiFi + Bluetooth SoC module — dual-core Xtensa LX6, the same silicon inside most ESP32 dev boards.

ESP32-WROOM-32E · Espressif Systems

Voltage

3–3.6V

Package

Module

Pins

Interfaces

CAN, I2C, I2S, SPI, UART

Lifecycle

Active

Footprint

Not verified

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Overview

The ESP32-WROOM-32E is the bare, castellated SMD module: a dual-core Xtensa LX6 SoC with WiFi and Bluetooth Classic/BLE, an SPI flash die, and a PCB antenna, all inside a 18×25.5mm shield can. It's what you'd reach for designing your OWN board around an ESP32 — most people building a project instead want a dev board (see esp32-devkit-v1) that has already wired up the USB-serial bridge, 3.3V regulator, EN/BOOT buttons and a breadboard-friendly header. The module itself needs a handful of support passives to run: a pull-up on EN, a pull-up on GPIO0 (to boot the flashed program instead of the ROM bootloader), and decoupling on 3V3.

Wiring tip: bare module — needs EN/GPIO0 pull-ups and its own 3.3V regulator; use esp32-devkit-v1 unless you're laying out your own board

Ecosystem: esp32

esp32wifibluetoothxtensamodule

Pins & wiring

01Pin map

38 positions · top view

Logical two-sided map — confirm the package or board drawing before wiring.

PowerGroundAnalogI2CSPIUARTControlOther

All pins

Hover · click to select

Selected pin

GND

Ground

Direction: Passive

Full pin table

Pin	Name	Role	Direction	Voltage	Note
1		Ground	Passive	—	—
2		Power	Power	3.3 V	—
3		Control	In	—	Active-low chip enable/reset. Needs an external pull-up (~10kΩ) to 3V3 to run — floating EN holds the chip in reset.
SENSOR_VP	silk: SENSOR_VP	Analog	In	3.3 V	Input-only, no pull resistors.
SENSOR_VN	silk: SENSOR_VN	Analog	In	3.3 V	Input-only, no pull resistors.
IO34		Analog	In	3.3 V	Input-only, no pull resistors.
IO35		Analog	In	3.3 V	Input-only, no pull resistors.
IO32		Analog	Bidirectional	3.3 V
IO33		Analog	Bidirectional	3.3 V
IO25		Analog	Bidirectional	3.3 V
IO26		Analog	Bidirectional	3.3 V
IO27		Analog	Bidirectional	3.3 V
IO14		SPI	Bidirectional	3.3 V
IO12		SPI	Bidirectional	3.3 V	Strapping pin (MTDI) — boot FAILS if externally pulled HIGH at reset.
14		Ground	Passive	—	—
IO13		SPI	Bidirectional	3.3 V
16		Other	No connect	—	Reserved for the internal SPI flash — not usable as GPIO.
17		Other	No connect	—	Reserved for the internal SPI flash — not usable as GPIO.
18		Other	No connect	—	Reserved for the internal SPI flash — not usable as GPIO.
19		Other	No connect	—	Reserved for the internal SPI flash — not usable as GPIO.
20		Other	No connect	—	Reserved for the internal SPI flash — not usable as GPIO.
21		Other	No connect	—	Reserved for the internal SPI flash — not usable as GPIO.
IO15		SPI	Bidirectional	3.3 V	Strapping pin (MTDO) — outputs debug info at boot; has an internal pull-up.
IO2		Analog	Bidirectional	3.3 V	Strapping pin — must be low or floating to enter flashing mode; commonly tied to the onboard LED on dev boards.
IO0		Analog	Bidirectional	3.3 V	Strapping pin — boot mode select. HIGH (or floating with its internal pull-up) = run firmware; LOW at reset = UART download mode.
IO4		Analog	Bidirectional	3.3 V	Not a strapping pin, despite being commonly assumed to be one.
IO16		UART	Bidirectional	3.3 V
IO17		UART	Bidirectional	3.3 V
IO5		SPI	Bidirectional	3.3 V	Strapping pin — outputs PWM briefly at boot.
IO18		SPI	Bidirectional	3.3 V
IO19		SPI	Bidirectional	3.3 V
32		Other	No connect	—	—
IO21		I2C	Bidirectional	3.3 V
RXD0	silk: RXD0	UART	Bidirectional	3.3 V	UART0 RX — shared with the USB-serial bridge on dev boards; avoid repurposing while using Serial.
TXD0	silk: TXD0	UART	Bidirectional	3.3 V	UART0 TX — shared with the USB-serial bridge on dev boards; avoid repurposing while using Serial.
IO22		I2C	Bidirectional	3.3 V
IO23		SPI	Bidirectional	3.3 V
38		Ground	Passive	—	—

Wiring examples

Minimal application circuit

Any 3.3V host

The support passives every WROOM-32E design needs, regardless of what else is on the board — this is what a dev board already does for you.

ESP32-WROOM-32E pin	Connects to	Note

You also need

Required10 kΩ resistor between EN and 3V3 — EN floating leaves the chip in an undefined/reset state — a pull-up lets it run on power-up.
Required10 kΩ resistor between GPIO0 and 3V3 — GPIO0 must read HIGH at reset to boot the flashed program instead of dropping into the UART bootloader.
Required100 nF capacitor between 3V3 and GND — 100nF decoupling right at the module's 3V3/GND pins, per Espressif's hardware design guidelines.
Required10 µF capacitor between 3V3 and GND — A bulk 10µF cap absorbs the current spikes during WiFi TX bursts — undersized decoupling is a common cause of brownout resets.

GPIO0, GPIO2, GPIO5, GPIO12 and GPIO15 are strapping pins — an external pull-up/down in the wrong direction can silently break boot or flashing.
Keep copper out of a 15mm zone around the PCB antenna on ALL layers — any ground pour or trace there detunes it off 2.4GHz.
This is a 3.3V-only part — none of its GPIOs are 5V tolerant.

Specifications

Electrical

Core: Xtensa dual-core 32-bit LX6src
Max Clock: 240 MHzsrc
Flash: Varies by vendor
SRAM: 520 KBsrc
Logic Voltage: 3.3 Vsrc
Operating Voltage: 3 – 3.6 Vsrc

Interface

GPIO Count: 34src
ADC Channels: 18src
ADC Resolution: 12 bitsrc
Wi-Fi: Yessrc
Bluetooth: Yessrc
Interfaces: i2c, spi, uart, i2s, cansrc

Physical

USB Connector: nonesrc
Package: Modulesrc
Length: 18 mmsrc
Width: 25.5 mmsrc
Height: 3.1 mmsrc
Mounting: smdsrc

Thermal

Min Operating Temp: -40 °Csrc
Max Operating Temp: 85 °Csrc

Footprint

No independently verified physical footprint is on file for this part yet.

Alternatives

Budget options

Cheaper, with a stated tradeoff — read the reason before swapping.

STM32F103C8T6 "Blue Pill"

Cheaper MCU option when a project doesn't need WiFi/Bluetooth at all.

Compare with ESP32-WROOM-32E

Wi-Fi: yes → no
Core: Xtensa dual-core LX6 @ 240MHz → ARM Cortex-M3 @ 72MHz — Different toolchain/ecosystem, not a drop-in firmware port.

Similar parts

Does the same job with a different part. Expect wiring and library changes — a starting point, not a guarantee.

ESP32 DevKit V1 (DOIT, 30-pin)

Same silicon, pre-integrated onto a dev board with USB-serial, a 3.3V regulator, EN/BOOT buttons and a breadboard-friendly header — skip your own antenna-keepout and power design.

Compare with ESP32-WROOM-32E

Form factor: bare SMD module → 30-pin breadboard devboard

Documents

Datasheets

ESP32-WROOM-32E / ESP32-WROOM-32UE DatasheetEspressif Systems

Product pages

ESP32-WROOM-32E product pageEspressif Systems

Frequently asked questions

What voltage does the ESP32-WROOM-32E run at?

The ESP32-WROOM-32E runs at 3–3.6V, per the spec sheet below. Always double-check against the specific board you have — some breakouts add an onboard regulator that changes the usable input range.

How many pins does the ESP32-WROOM-32E have?

The ESP32-WROOM-32E has 38 pins, communicating over CAN, I2C, I2S, SPI, UART. See the full pinout table in Pins & wiring for each pin's role.

Can I simulate the ESP32-WROOM-32E before ordering hardware?

Not yet — the ESP32-WROOM-32E does not have a live simulation model in Banana Board today, so validate the wiring here and test on real hardware.

Where is the ESP32-WROOM-32E datasheet?

Linked in the Documents section on this page, and cited on every spec that came from it.

Related references

Parts catalogue Microcontrollers Board pinouts Component & symbol search

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