ESP8266EX Pinouts and Connections

ESP8266EX Pin Locations

The image below shows the ESP8266EX Pin Locations

esp8266-ex-pinouts

ESP8266 Pin Functions

PinNameTypeDescription
1VDDAPowerAnalog Power
3.0 - 3.6 Volts
2LNAAntennaRF Antenna Interface
3VDD3P3PowerAmplifier Power
3.0 - 3.6 volts
4VDD3P3PowerAmplifier Power
3.0 - 3.6 Volts
5VDD_RTCPOWERNC(1.1)
6TOUTInputADC Input
7CHIP_PUInputChip Enable
High = Fully Functional
Low = Sleep Mode
8XPD_DCDCI/OGPIO 16
Deep Sleep Wake Up
9MTMSI/OGPIO 14
HSPI_CLK
10MTDII/OGPIO 12
HSPI_MISO
11VDDPSTPOWERDigital/IO Power Supply
1.8 - 3.3V
12MTCKI/OGPIO 13
HSPI_MOSI
UART0_CTS
13MTDOI/OGPIO 15
HSPI_CS
UART0_RTS
14GPIO2I/OGPIO 2
UART Tx during flash programming
15GPIO0I/OGPIO 0
SPI_CS2
16GPIO4I/OGPIO 4
17VDDPSTPOWERDigital/IO Power Supply
1.8 - 3.3V
18SDIO_DATA_2I/OGPIO 9
Connect to SD_D2 (Series R: 200Ω)
SPIHD
HSPIHD
19SDIO_DATA_3I/OGPIO 10
Connect to SD_D3 (Series R: 200Ω)
SPIWP
HSPIWP
20SDIO_CMDI/OGPIO 11
Connect to SD_CMD (Series R: 200Ω)
SPI_CS0
21SDIO_CLKI/OGPIO 6
Connect to SD_CLK (Series R: 200Ω)
SPI_CLK
22SDIO_DATA_0I/OGPIO 7
Connect to SD_D0 (Series R: 200Ω)
SPI_MSIO
23SDIO_DATA_1I/OGPIO 8
Connect to SD_D1 (Series R: 200Ω)
SPI_MOSI
24GPIO5I/OGPIO 5
25U0RXDI/OGPIO 3
UART Rx during flash programming
26U0TXDI/OGPIO 1
UART Tx during flash programming
SPI_CS1
27XTAL_OUTCRYSTALConnect to crystal oscillator output, can be used to provide BT
clock input
28XTAL_INCRYSTALConnect to crystal oscillator input
29VDDDPOWERAnalog Power
3.0V - 3.6V
30VDDAPOWERAnalog Power
3.0V - 3.6V
31RES12KINPUT12K Ohm +/1% Resistor is placed in series with this pin and other side of resistor is connected to ground
32EXT_RSTBINPUTExternal Reset
Low is Active
33GRNDGROUNDThis is not technically a pin. Instead it refers to the ground plane on the bottom of the chip.