Datasheet

Power Pins
GND - this is the common ground for all power and logic
BAT - this is the positive voltage to/from the JST jack for the optional Lipoly battery
USB - this is the positive voltage to/from the micro USB jack if connected
EN - this is the 3.3V regulator's enable pin. It's pulled up, so connect to ground to disable the 3.3V regulator
3V - this is the output from the 3.3V regulator, it can supply 500mA peak (try to keep your current draw under
250mA so you have plenty for the ESP8266's power requirements!)
Logic pins
This is the general purpose I/O pin set for the microcontroller. All logic is 3.3V
Serial pins
RX and TX are the serial control and bootloading pins, and are how you will spend most of your time communicating
with the ESP module
The ESP8266 runs on 3.3V power and logic, and unless otherwise specified, GPIO pins are not 5V safe! The
analog pin is also 1.0V max!
© Adafruit Industries https://learn.adafruit.com/adafruit-feather-huzzah-esp8266 Page 9 of 43