Espressif Systems ESP8266EX - Page 13

CONFIDENTIAL
Espressif
Systems
ESP8266EX Beginner’s Guide
Note: GPIO2, GPIO0, MTDO can be configurable as 3-bit SDIO mode"
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
Deep-Sleep Wakeup；GPIO16
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
UART Tx during flash progamming; GPIO2
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
UART Rx during flash progamming; GPIO3
26
U0TXD
I/O
UART Tx during flash progamming; GPIO1; 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)
! | Page" " September 17, 2014 13