Espressif Systems ESP8266EX - Page 33

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Espressif Systems
ESP8266EX
Hardware User Guide
Table 5 Pin Definitions of ESP-WROOM-02 WiFi Module
Connect the 3.3V power-supply pin to an external 3.3V power source, for 3.3V is the power-supply
for both analog circuit and digital circuit.
When working, normally the voltage level of the EN pin, WiFi enable pin, should be set high.
SMD Module features two working modes: one is UART Download mode, the other is Flash Boot
mode. UART Download mode means that user programs can be written into the Flash or Memory by
flash downloading tools. If the programs are burnt into the Memory, the programs can run only when
the device is powered on, once the device is powered off, the programs in the Memory will be
erased. However, when the programs are burnt into the Flash, they will be stored in it, and can be
invoked and used at any time.
NO.
Pin Name
Function
1
3V3
3.3V power supply (VDD)
2
EN
Chip enable pin. Active high.
3
IO14
GPIO14; HSPI_CLK
4
IO12
GPIO12; HSPI_MISO
5
IO13
GPIO13; HSPI_MOSI; UART0_CTS
6
IO15
GPIO15; MTDO; HSPICS; UART0_RTS
7
IO2
GPIO2; UART1_TXD
8
IO0
GPIO0
9
GND
GND
10
IO4
GPIO4
11
RXD
UART0_RXD; GPIO3
12
TXD
UART0_TXD; GPIO1
13
GND
GND
14
IO5
GPIO5
15
RST
Reset the module
16
TOUT
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.
17
IO16
GPIO16; can be used to wake up the chipset from deep sleep mode.
18
GND
GND
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