IoT Bytes

Bits and Bytes of IoT

ESP8266 Pinout

Pradeep Singh | 4th April 2016

pins

ESP8266 Pins (component side up):

esp8266-5


Following are the details of each of these Pins –

Pin Description
VCC 3.3V (3.6V Max) Power Supply Pin
GND Ground Pin
Tx Data Transmit Pin (Works at 3.3V)
Rx Data Receive Pin (Works at 3.3V)
CH_PD Chip Power Down Pin. (LOW = Power Down, HIGH = Power UP). Connect this Pin to VCC Pin.
GPIO 0 General Purpose I/O Pin 0 (I/O Index 3)
GPIO 2 General Purpose I/O Pin 2 (I/O Index 4)
RESET Reset Pin (LOW = Reset). Pull Down this Pin by connecting it to GND Pin to reset ESP8266

ESP8266EX Chip Pinout:

ESP8266EX Chip Pins

Pin Name Type Function
1 VDDA P Analog Power 3.0 V ~ 3.6V
2 LNA I/O RF Antenna Interface
Chip Output Impedance = 50 Ω
No matching required. It is suggested to retain the π-type
matching network to match the antenna.
3 VDD3P3 P Amplifier power: 3.0 V ~ 3.6 V
4 VDD3P3 P Amplifier power:3.0 V ~ 3.6 V
5 VDD_RTC P NC (1.1 V)
6 TOUT I ADC pin. It can be used to test the power-supply voltage of
VDD3P3 (Pin3 and Pin4) and the input power voltage of
TOUT (Pin 6). However, these two functions cannot be used
simultaneously
7 CHIP_EN I Chip Enable
High: On, chip works properly
Low: Off, small current consumed
8 XPD_DCDC I/O Deep-sleep wakeup (need to be connected to EXT_RSTB;
GPIO16
9 MTMS I/O GPIO14; HSPI_CLK
10 MTDI I/O GPIO12; HSPI_MISO
11 VDDPST P Digital / IO power supply (1.8 V ~ 3.3 V)
12 MTCK I/O GPIO13; HSPI_MOSI; UART0_CTS
13 MTDO I/O GPIO15; HSPI_CS; UART0_RTS
14 GPIO2 I/O UART Tx during flash programming; GPIO2
15 GPIO0 I/O GPIO0; SPI_CS2
16 GPIO4 I/O GPIO4
17 VDDPST P Digital / IO power supply (1.8 V ~ 3.3 V)
18 SDIO_DATA_2 I/O Connect to SD_D2 (Series R: 200 Ω); SPIHD; HSPIHD;
GPIO9
19 SDIO_DATA_3 I/O Connect to SD_D3 (Series R: 200 Ω); SPIWP; HSPIWP;
GPIO10
20 SDIO_CMD I/O Connect to SD_CMD (Series R: 200 Ω); SPI_CS0; GPIO11
21 SDIO_CLK I/O Connect to SD_CLK (Series R: 200 Ω); SPI_CLK; GPIO6
22 SDIO_DATA_0 I/O Connect to SD_D0 (Series R: 200 Ω); SPI_MSIO; GPIO7
23 SDIO_DATA_1 I/O Connect to SD_D1 (Series R: 200 Ω); SPI_MOSI; GPIO8
24 GPIO5 I/O GPIO5
25 U0RXD I/O UART Rx during flash programming; GPIO3
26 U0TXD I/O UART Tx during flash programming; GPIO1; SPI_CS1
27 XTAL_OUT I/O Connect to crystal oscillator output, can be used to provide
BT clock input
28 XTAL_IN I/O Connect to crystal oscillator input
29 VDDD P Analog power 3.0 V ~ 6 V
30 VDDA P Analog power 3.0 V ~ 3.6 V
31 RES12K I Serial connection with a 12 kΩ resistor to the ground
32 EXT_RSTB I External reset signal (Low voltage level: Active)

 

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