ESP8266 Pin Diagram

ESP8266EX is among the most integrated WiFi chip in the industry; it integrates the antenna switches, RF balun, power amplifier, low noise receive amplifier, filters, power management modules, it requires minimal external circuitry, and the entire solution, including front-end module, is designed to occupy minimal PCB area. ESP8266EX also integrates an enhanced version of Tensilica’s L106 Diamond series 32-bit processor, with on-chip SRAM, besides the WiFi functionalities. ESP8266EX is often integrated with external sensors and other application specific devices through its GPIOs; sample codes for such applications are provided in the software development kit (SDK).


  • Integrated low power 32-bit MCU
  • Integrated TCP/IP protocol stack
  • Integrated TR switch, balun, LNA, power amplifier and matching network
  • 802.11 b/g/n WiFi 2.4 GHz, support WPA/WPA2
  • Support STA/AP/STA+AP operation modes
  • 10-bit ADC, SDIO 2.0, (H) SPI, UART, I2C, I2S, IR Remote Control, PWM, GPIO
  • Deep sleep power <10uA, Power down leakage current < 5uA
  • Wake up and transmit packets in < 2ms
  • Standby power consumption of < 1.0mW (DTIM3)
  • +20 dBm output power in 802.11b mode
  • Operating temperature range -40C ~ 125C
  • FCC, CE, TELEC, WiFi Alliance, and SRRC certified

ESP8266 ESP-12 Pin Out

ESP-12 PinOut
ESP-12 Pin Out

ESP8266 ESP-01 Pin Out

ESP-01 Pin Out
ESP-01 Pin Out

There is no difference in programming ESP-12 or ESP-01, The difference is of only the number of IOs available on the board.

Pin Definition

Name Type Function
VCC P Power 3.0 ~ 3.6V
GND P Ground
RESET I External reset signal (Low voltage level: Active)
ADC(TOUT) I ADC Pin Analog Input 0 ~ 1V
CH_PD I Chip Enable. High: On, chip works properly; Low: Off, small current
GPIO0(FLASH) I/O General purpose IO, If low while reset/power on takes chip into serial programming mode
GPIO1(TX) I/O General purpose IO and Serial TXd
GPIO3(RX) I/O General purpose IO and Serial RXd
GPIO4 I/O General purpose IO
GPIO5 I/O General purpose IO
GPIO12 I/O General purpose IO
GPIO13 I/O General purpose IO
GPIO14 I/O General purpose IO
GPIO15(HSPI_CS) I/O General purpose IO, Connect this pin to ground through 1KOhm resistor to boot from internal flash.

Note: TX1 and TX GPIO1 are internally connected, On board blue LED is also connected to this pin

Electrical Characteristics

Working Voltage: 3.3V

Maximum IO Driving Power IMAX: 12 mA

Maximum IO Voltage Level VMAX: 3.6V

Current Consumption: 100mAmp

ESPWitty Cloud Module Pin Connections

ESPWitty Pin Diagram
ESPWitty Pin Diagram



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