Chengdu Ebyte Electronic Technology Co., Ltd.
E104-BT20 User Manual
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Copyright ©2012–2020, Chengdu Ebyte Electronic Technology Co., Ltd.
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7. Quick Use
7.1 Enter AT command mode
Connect the Bluetooth module E104-BT20 to the USB interface of the PC, and open the serial port debugging assistant on the PC
side to debug the module.
First, the AT test instruction. After ensuring that the MOD pin is set low (the default is low), the module is powered on, and then
the MOD pin is set high to enter the AT instruction mode. When sending the command, the serial port debugging assistant should
select "enter key line feed" and set the serial port parameter baud rate 9600bps, 1 stop bit, no parity check. If the command AT is sent,
it returns OK. Then the module successfully enters the AT instruction mode and can use other AT instructions.
7.2 Auto Connection
Module default parameters: Specify connection mode, slave role, baud rate 9600bps, 1 stop bit, no parity. When the module is
powered on, it is a slave role. Enter the AT command mode and send "AT + ADDR?" To query the Bluetooth module address to
facilitate the host connection.
Set another module to enter the AT command mode, set the baud rate of the serial tool to 9600bps, and send the command "AT +
ROLE = 1". If successful, it will return OK. Assume that the slave address is 11: 22: 33: 44: 55: 66, because the default mode is
"Specify Bluetooth connection mode", you only need to set the binding Bluetooth address to the slave's Bluetooth address to
automatically connect the slave, Send the command "AT + BIND = 11,22,33,44,55,66". If it returns OK, the setting is successful.
Restart the module. At this time, the module as the master has taken effect. After the host is powered on, it will automatically establish
a connection with the slave.
8. Notice for Hardware
It is recommended to use DC stabilized power supply. The power supply ripple factor should be as small as possible, and
the module should be reliably grounded.
Please ensure that the positive and negative poles of the power supply are properly connected. If the reverse connection is
made, the module may be permanently damaged.
Please ensure the power supply voltage is within the working voltage range. If the maximum voltage is exceeded, the
module will be permanently damaged.
Please check the stability of the power supply, and the voltage cannot be fluctuated frequently;
When designing the power supply circuit for the module, it is recommended to reserve more than 30% of the margin to
achieve long-term stable operation of the system;
The installation location of the module should be as far away as possible from the power supply, transformers,
high-frequency wiring and other parts with large electromagnetic interference;
High-frequency digital routing, high-frequency analog routing, and power routing must avoid module locations. If the
wiring must pass under the module, assuming that the module is soldered to the Top Layer, the area where the module is in
contact with the Top Layer should be covered with copper (all copper is well grounded), and the area must be close to the digital
