Embedded hardware reference for engineers and makers

Wemos D1 Mini v3.0 Pinout & Hardware Reference

16-pin interactive pinout

Wemos D1 Mini v3.0 is a compact, breadboard-friendly IoT development board powered by the Espressif ESP8266EX SoC (discrete bare-chip architecture without shield can). Featuring 11 digital I/O pins, 1 analog input with integrated divider, and an onboard CH340C USB-UART bridge, it is one of the most accessible Wi-Fi microcontrollers.

  • LOLIN / Wemos
  • Verified source
  • Updated Sep 2026

Interactive pinout diagramTop

  • GPIO
  • Power
  • Ground
  • Analog
  • Control

Tap a row of pins to see it up close

Wemos D1 Mini v3.0 (ESP8266) Pinout Vector DiagramInteractive vector pinout diagram of Wemos D1 Mini v3.0 (ESP8266) (top view) showing pin headers, power rails, components, and hardware interfaces.ESP8266EXDCL0CH4MB4MBS426.0004MBD1SRESETUSBRSTA0D0D5D6D7D83V3TXRXD1D2D3D4G5V

BOARD SUMMARY

ESP8266EX

Wemos D1 Mini v3.0 (ESP8266)

ESP8266EX

LOLIN / Wemos
MCU
ESP8266EX
CPU core
Tensilica Xtensa 32-bit LX106
Clock speed
80 MHz
SRAM
80 KB
Flash
4 MB
GPIO count
11
Logic voltage
3.3 V (not 5 V tolerant)
Form factor
16-pin, USB-to-Serial (WCH CH340C)

Before you wire

GPIO is not 5 V tolerant

  • Deep Sleep Auto-Wake vs Flashing: Soldering the SLEEP jumper (connecting D0 to RST) enables deep sleep wake-up, but can interfere with auto-reset during firmware upload.
  • Analog Input Range: Unlike bare ESP8266 modules (0-1.0V max), the D1 Mini has an onboard 220k/100k divider allowing safe measurement up to 3.2V.
  • Strictly 3.3V Logic: ESP8266 GPIO pins are not 5V tolerant. Connecting 5V sensors directly requires a bidirectional logic level shifter.
  • Strapping Pin Traps: D8 (GPIO15) must not be pulled HIGH at boot. D3 (GPIO0) pulled LOW enters bootloader flashing mode.

QUICK LINKS

Pin table

Showing 16 of 16 pins
Wemos D1 Mini v3.0 (ESP8266) pin table: physical pin, name, GPIO, functions, ADC, touch, default role, flags
PinNameGPIOFunctionsADCDefault roleFlags
1 leftRST—
reset
—Reset / EnableConnecting to D0 (GPIO16) via SLEEP solder jumper enables RTC Deep Sleep wake-up. Disconnect during flashing.
2 leftA0—
adc
ADC_CH0GPIOIntegrated 220k/100k voltage divider scales 0-3.2V input to raw 0-1.0V TOUT pin.
3 leftD0GPIO16
gpiortc
—GPIOConnected to RTC timer output. Solder bridge with RST allows automatic wake-up from Deep Sleep.
4 leftD5GPIO14
gpiospipwm
—GPIO
5 leftD6GPIO12
gpiospipwm
—GPIO
6 leftD7GPIO13
gpiouartspipwm
—GPIO
7 leftD8GPIO15
gpiospipwmstrap
—Mode / StrappingBoot strapping pin: must be LOW at boot. Pulled down to GND with onboard 10k resistor.
8 left3V3—
power
—3.3 V Power3.3V system power rail supplied by onboard ME6211 LDO regulator (max 500mA).
1 rightTXGPIO1
gpiouart
—GPIODirectly connected to CH340C USB-UART bridge RXD line.
2 rightRXGPIO3
gpiouart
—GPIODirectly connected to CH340C USB-UART bridge TXD line.
3 rightD1GPIO5
gpioi2cpwm
—GPIO
4 rightD2GPIO4
gpioi2cpwm
—GPIO
5 rightD3GPIO0
gpiopwmstrap
—Mode / StrappingBoot strapping pin: must be HIGH for normal boot; LOW enters UART flash download mode. Pulled up with onboard 10k resistor.
6 rightD4GPIO2
gpiouartpwmstrap
—Mode / StrappingBoot strapping pin: must be HIGH at boot. Connected to onboard blue user LED (active LOW). Pulled up with onboard 10k resistor.
7 rightG—
gnd
—Ground
8 right5V—
power
—5.0 V Power5V power input from Micro-USB or external power to onboard ME6211 LDO regulator.

Grounded reference

Board overview

The Wemos D1 Mini v3.0 combines the ESP8266EX 80/160 MHz microcontroller with 4MB Flash and an onboard USB-UART bridge into a miniature 25.6x34.2mm form factor. It supports a vast ecosystem of stackable shields (relays, sensors, motor drivers, OLEDs).

Power inputs

  • 5V USB / Header: 5V DC input from Micro-USB or external power directly feeds the ME6211 3.3V 500mA LDO regulator.
  • 3V3 Pin: Regulated 3.3V rail powering the ESP-12F module and external low-power peripherals. Max available current ~450 mA.
  • SLEEP Solder Jumper: Located on the bottom layer, linking GPIO16 (D0 / WAKE) to the RST pin for automatic RTC wake-up from Deep Sleep.

Hardware Variants, Clones & Traps

  • Wemos D1 Mini V3.0: Features CH340C USB chip (eliminating external crystal), ME6211 LDO, improved reset circuit, and sleep solder jumper.
  • D1 Mini Pro: Advanced variant featuring 16MB Flash, CP2104 USB chip, ceramic chip antenna, and external I-PEX antenna connector.

Before you wire

  • Deep Sleep Auto-Wake vs Flashing: Soldering the SLEEP jumper (connecting D0 to RST) enables deep sleep wake-up, but can interfere with auto-reset during firmware upload.
  • Analog Input Range: Unlike bare ESP8266 modules (0-1.0V max), the D1 Mini has an onboard 220k/100k divider allowing safe measurement up to 3.2V.
  • Strictly 3.3V Logic: ESP8266 GPIO pins are not 5V tolerant. Connecting 5V sensors directly requires a bidirectional logic level shifter.
  • Strapping Pin Traps: D8 (GPIO15) must not be pulled HIGH at boot. D3 (GPIO0) pulled LOW enters bootloader flashing mode.

Specifications

MCU
ESP8266EX
CPU core
Tensilica Xtensa 32-bit LX106
Clock
80 MHz
SRAM
80 KB
Flash
4 MB
Wireless
Wi-Fi 802.11 b/g/n (2.4 GHz)
GPIO count
11
Logic voltage
3.3 V
Operating voltage (VIN)
4.75 - 10 V

Safe GPIO pins

Operates at 3.3V logic level. ESP8266 GPIO pins are NOT 5V tolerant (max 3.6V). The 5V pin powers the onboard ME6211 3.3V LDO regulator (up to 500 mA output).

ADC and analog pins

Pin A0 connects to an integrated 220 kΩ / 100 kΩ voltage divider, scaling external voltages up to 3.2V to the raw 0-1.0V ESP8266 TOUT ADC channel.

I2C, SPI and UART pins

Hardware UART0 on TX/RX (shared with USB). Software/Hardware SPI on D5 (SCK), D6 (MISO), D7 (MOSI), D8 (SS). I2C bus default on D1 (SCL) and D2 (SDA).

Strapping and boot pins

Boot configuration strapping pins: D3 (GPIO0) pull-up for Flash mode; D4 (GPIO2) pull-up, drives blue onboard LED; D8 (GPIO15) pull-down, must be LOW at boot.

Input-only pins

Bidirectional GPIO pins feature internal software-configurable pull-ups (~30-100 kΩ) except GPIO16 (D0) which has a built-in pull-down.

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