Chengdu Ebyte Electronic Technology Co., Ltd.
E104-BT20 User Manual
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Copyright ©2012–2020, Chengdu Ebyte Electronic Technology Co., Ltd.
5
7
LINK
Output
LED indicator
Module connection indicator Output pin
②
8
MOD
Input
modification
Input high level, the module enters configuration mode, input low level, the module enters
transparent transmission mode
9
MCU_MOD
E
Input
-
(This pin has internal pull-down, and works in transparent transmission mode by default)
10
GND
-
Power Supply Ground
High level enters online programming mode, low level is working mode
11
GPIO3
Suspension
Universal IO
Ground, connected to the power reference ground
12
GPIO4
Suspension
Universal IO
Pin for User configuration
13
GPIO5
Suspension
Universal IO
Pin for User configuration
14
GPIO6
Suspension
Universal IO
Pin for User configuration
15
RESETB
Input
Module reset pin
(RST)
Pin for User configuration
16
GND
-
Power Supply Ground
The low-level input module enters the hardware reset state, and the high-level input
module returns to the normal working state. This function is used for reset operation in
emergency
17
GND
-
Power Supply Ground
Ground, connected to the power reference ground
18
VCC
Input
3.3V
Ground, connected to the power reference ground
19
GND
-
Power Supply Ground
Power Supply Input
20
GPIO7
Suspension
Universal IO
Ground, connected to the power reference ground
21
CTS
Input
Hardware flow control
Pin for User configuration
22
STATUS
Output
LED indicator
UART clear transmit input pin
23
TXD
Output
TX Power Ground
Module status indicator Output pin
①
24
RTS
Output
Hardware flow control
Module external output serial data
25
RXD
Input
RX Serial Port
UART request send input pin
26
GND
-
Power Supply Ground
Module receives external serial data
Note 1: Following the AT + POLAR setting instruction, the module status indicator output pin defaults to output a high level to light
up the LED.
Normal configuration mode (MOD pin is low level, then power on the module, the baud rate is same with the one from last power off.,
the default value is 9600bps)
Before the host is connected,
Fast flashing: when the master does not record the slave address;
Slow flashing: when recording slave address;
After connecting, two flashes and one stop.
Slave / Slave Loopback
Flashes quickly before connecting;
After connecting, two flashes and one stop;
Power-on configuration mode
(set MOD pin high first, then power on the module, baud rate is fixed at 38400bps)
The LED keeps lighting up every 2 seconds for 1 second at whole process.
Note 2: Following AT + POLAR setting instructions, the output pin of the module's connection indicator defaults to light up the LED
by outputting a high level.
Before connecting,
The LED is off.
Once connected,
The LED light is always on
