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Getting Started with ESP8266EX-WIFI-MOD

  • ESP8266EX-WIFI-MOD is the most common module with Espressif’s WiFi SoC. Module, also known as ESP-1, has integrated PCB antenna, Quad SPI flash 25Q40B and 2×4 pin 2.54mm  connector. There are two LED’s on the board, one is POWER LED, another one is STATUS LED. PCB size 14.2 x 24.5 mm.

ESP8266EX-WIFI-MOD pinout


Pin Description
VCC 3.3V
GND Ground
TX Transmit Data
RX Receive Data
CH_PD Chip Power Down: (aktive LOW – Power Down)
GPIO0 General Purpose I/O 0
GPIO2 General Purpose I/O 2
RST Reset (aktive LOW – Reset Chip)


The correspondence between module pins and ESP8266EX

Module ESP8266EX
TX      UTXD (pin 26)
GPIO2  GPIO2 (pin 14)
CH_PD  CHIP_EN (pin 7)
RESET  EXT_RST (pin 32)
GPIO0  GPIO0 (pin 15)
RX       URXD (pin 25)


Wiring for normal operational mode

ESP-1 µC
  • Power supply pins VCC/GND to connect to power source 3.3V@500mA (max 3.6V).
  • UART pins RX/TX connect according to table. Pins RX/TX are not 5V tolerant,  make sure your micro-controller or PC’s USB serial interface has capability of 3.3V UART signals.
  • General Purpose I/O’s  GPIO0 & GPIO2 unused by current supplied firmware.
  • Chip Power Down pin CH_PD pullup with resistor to power supply pin VCC.
  • Chip Reset pin RST pullup with resistor to power supply pin VCC.



Module ESP8266-WiFi-MOD comes programmed with UART-WIFI bridge demo software. Communication with module is done with simple AT commands. Default communication parameters are 115200bps, 8N1. To use module on your PC (Windows/Linux/Mac) needed:

  • USB TTL Serial Interface, eg. USB-TTL-SERIAL-MOD  and
  • Serial Communications Program, eg. minicom configured with default communication parameters.

Connect module as described above and test module. Here is communication example:




Command AT+GMR is query of the firmware version. In this case 0016 is version of developing tools and 0901 show version of SDK used to generate firmware. AT command list v.09.1 is available here.


ESP8266EX Compiler

Current version of SDK is v 0.92. Source code  is available from Espressif’s web site You can add new  or modify exciting AT commands and compile with open source tool-chain available thanks to jcmvbkbc contributed to ESP8266EX community forum. Here is example how to create new AT command.

This cross-compiler  officially  is supported from chip manufacturer – Espressif. They have prepared Lubuntu VM with  installed cross-compiler. Virtual Machine is available here, password  qudl.  If you prefer to compile tool-chain from sources, instructions  are at ESP8266 community forum wiki page.

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