User's Manual

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2. ESP-WROOM-02D Pin Description
7
IO2
GPIO2; UART1_TXD
Floating (internal pull-up) or pull up.
8
IO0
GPIO0
•
UART download: pull down.
•
Flash boot: floating or pull up.
9
GND
GND
10
IO4
GPIO4
11
RXD
UART0_RXD, receive end in UART download;
GPIO3
12
TXD
UART0_TXD, transmit end in UART download, floating or pull up;
GPIO1
13
GND
GND
14
IO5
GPIO5
15
RST
Reset
16
TOUT
It can be used to test the power-supply voltage of VDD3P3 (Pin3 and
Pin4) and the input power voltage of TOUT (Pin6). These two functions
cannot be used simultaneously.
17
IO16
GPIO16; used for Deep-sleep wake-up when connected to RST pin.
18
GND
GND
No.
Pin Name
Functional Description
Espressif
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2017.11