ESP8266 GPIO3

GPIO3 / RXD / U0RXD / I2SO_DATA

Use with care - Fine for many uses, but check the warnings below first.

What GPIO3 can do

Digital input/output
PWM output (software)
UART (fixed IO MUX pins)
i2s

Warnings for GPIO3

Serial console

UART0. The bootloader prints its log here at boot and this is the flashing port. Usable as GPIO, but you lose the console and anything attached sees boot noise.

Open the interactive ESP8266 pinout →

All ESP8266 pins

GPIO0 · GPIO1 · GPIO2 · GPIO3 · GPIO4 · GPIO5 · GPIO6 · GPIO7 · GPIO8 · GPIO9 · GPIO10 · GPIO11 · GPIO12 · GPIO13 · GPIO14 · GPIO15 · GPIO16 · A0

ESP32 Pinout Studio - free interactive pinout reference. Pin data generated from KiCad's own stock symbol and footprint libraries (Espressif publishes no ESP8266 KiCad data). esp32pin.com