Pin definition

themindfactory edited this page Nov 29, 2014 · 5 revisions

ESP8266EX chip pinout is something like this:

ESP8266EX Pin Layout Diagram

Pin Name Type GPIO Function Conditions for use
1 VDDA P Analog Power 3.0 ~3.6V
2 LNA I/O RF Antenna Interface,Chip Output Impedance=50 Ω No matching required but we recommend that the π- type matching network is retained.
3 VDD3P3 P Amplifier Power 3.0~3.6V
4 VDD3P3 P Amplifier Power 3.0~3.6V
5 VDD_RTC P NC(1.1V)
6 TOUT I ADC Pin
7 CHIP_EN I Chip Enable. High: On, chip works properly; Low: Off, small current
8 XPD_DCDC I/O GPIO16 Deep-Sleep Wakeup
9 MTMS I/O GPIO14 HSPICLK
10 MTDI I/O GPIO12 HSPIQ
11 VDDPST P Digital/IO Power Supply (1.8V~3.3V)
12 MTCK I/O GPIO13 HSPID
13 MTDO I/O GPIO15 HSPICS
14 GPIO2 I/O GPIO2 UART Tx during flash progamming
15 GPIO0 I/O GPIO0 SPICS2
16 GPIO4 I/O GPIO4
17 VDDPST P Digital/IO Power Supply (1.8V~3.3V)
18 SDIO_DATA_2 I/O Connect to SD_D2 (Series R 200Ω);SPIHD; HSPIHD
19 SDIO_DATA_3 I/O Connect to SD_D3 (Series R 200Ω); SPIWP; HSPIWP
20 SDIO_CMD I/O Connect to SD_CMD(Series R 200Ω); SPICS0
21 SDIO_CLK I/O Connect to SD_CLK (Series R 200Ω); SPICLK
22 SDIO_DATA_0 I/O Connect to SD_D0 (Series R 200Ω); SPIQ
23 SDIO_DATA_1 I/O Connect to SD_D1 (Series R 200Ω); SPID
24 GPIO5 I/O GPIO5
25 U0RXD I/O GPIO3 UART Rx during flash progamming
26 U0TXD I/O GPIO1 UART Tx during flash progamming; SPICS1
27 XTAL_OUT I/O Connect to crystal output, can be used to provide BT clock input
28 XTAL_IN I/O Connect to crystal input
29 VDDD P Analog Power 3.0~3.6V
30 VDDA P Analog Power 3.0~3.6V
31 RES12K I Connect to series R 12kΩ to ground
32 EXT_RSTB I External reset signal (Low: Active)
Note: GPIO2, GPIO0, MTDO can be configurable as 3-bit SDIO mode