Chengdu Ebyte Electronic Technology Co., Ltd.
E104-BT20 User Manual
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Copyright ©2012–2020, Chengdu Ebyte Electronic Technology Co., Ltd.
6
5. Working Mode
5.1 Configuration mode (module enters AT mode)
There are two configuration modes:
normal configuration mode
and
power-on configuration mode
.
In normal configuration mode
, pull the MOD pin low before the module is powered on (the default setting is pull
down). After the module is powered on, set the MOD pin high again to enter the AT command mode. The parameters of
the serial port are the values successfully set by the user before the last power-off (the default value is 9600bps, 1 stop bit,
no parity bit). Now, the user can operate all AT commands; after Bluetooth connection, it will automatically enter the
transparent transmission mode. If the user needs to set the MOD pin high again to enter the AT command mode where the
module can’t receive data from other modules. If the MOD pin is set low, it will exit the AT command mode and return to
the transparent transmission mode. After disconnecting, the module is in AT command mode, and user can continue the
inquiry/setting operation. If the user forgets the baud rate or gets a module that has been set with certain parameters, user
can set the module to enter the power-on configuration mode and reset the baud rate.
NOTE: Some instructions are only available under certain mode, such as: CONNECTED mode or MASTER mode.
Details will be given in Chapter 6.
Power-on configuration mode
. Setting the MOD pin high and the module will immediately enter the AT command
mode after power-on. The status light will keep flashing slowly. In this mode, the module will not enter the connection
state. The other parameters are the same as the values saved since the last power-off. After setting the baud rate, restarting
the module and entering the normal configuration mode to use the new baud rate. All commands are available except for
"AT + LINK", "AT + RNAME", "AT + RSSI", and "AT + DISC" .
5.2 Working Role Changing
The module can be configured into three working roles: master, slave, and loopback. The master role supports the
automatic connection function; the slave and slave loopback support passive connection; the slave loopback can receive
data from the peer Bluetooth master device and return the data to the peer Bluetooth as is.
Steps to switch module roles:
Firstly, Enter the module's AT instruction mode
Secondly,. Use the serial port debugging assistant, send the AT command "AT + ROLE = <param>", and use the Enter
key to change the line. For details, see the AT command section. If the communication is successful, it returns "OK" and
the module role is still the original working role.
Thirdly, Set the MOD pin to low level and power on again to enter the normal configuration mode. At this time, the
module's working role takes effect.
