AT command set:
Module parameters, AT command set
AT command is used to set the parameters of the function module and switching modules need to exit the setting mode after setting to take effect. Meanwhile, modify the parameters and functions, power-down is not lost.
Enter the command mode:
The first entry mode – normal use (has the power) in the first 5-pin “SET” is set low;
The second mode of entry – power, 5th pin “SET” again first set low on power.
Both methods can make the module into AT command mode, release (“SET” pin is not connected low) to exit command mode. After the exit command mode, if you change the module function, the function will be cut to the appropriate state.
The second way is fixed in serial format 9600, N, 1 into the AT.
Example: Send module commands “AT”, the module returns “OK”.
2. AT + Bxxxx
Change the serial port baud rate command. You can set the baud rate is 1200bps, 2400bps, 4800bps, 9600bps, 19200bps, 38400bps, 57600bps and 115200bps. The factory default is 9600bps.
Example: Set the module serial port baud rate is 19200bps, please send module command “AT + B19200”, the module returns
“OK + B19200”.
3. AT + Cxxx
Change the wireless communication channel, selectable from 001 to 127 (more than 100 radio channels after the communication distance not guaranteed). The default value is 001 radio channels, operating frequency is 433.4MHz. Step channel is 400KHz, the operating frequency of the channel 100 is 473.0 MHz.
Set module to channel 21, please send module command “AT + C021”, the module returns “OK + C021”.
After exiting the command mode, the module in the first 21 channels, operating frequency is 441.4 MHz.
Note: Because the wireless receiver module sensitivity HC-12 is relatively high, the baud rate is greater than when air 58000 bps, 5 must be shifted to the adjacent channel use. When the air baud rate is not greater than 58000 bps, if the short distance (10 meters) communication, but also need to stagger five adjacent channel use.
4. AT + FUx
Change the module serial pass-through mode, there FU1, FU2, and FU3 three modes. Module default mode is FU3, two serial pass-through mode module must be set to the same communication. See detailed above, “wireless serial pass-through” part.
Example: Send module commands “AT + FU1”, the module returns “AT + OK”.
5. AT + Px