User Manual
HC‐12WIRELESSRFUARTCOMMUNICATIONMODULEV2.4USERMANUAL
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PAGE 3
Wireless UART transmission
⑴ Brief introduction of the working principle
As shown in the figure above, the HC-12 module is used to replace the physical connection
in half duplex communication. On the left side of the device to send UART data to module, the
module's RXD port after receiving the UART data, the data automatically transmitted to the air
in the way of radio. On the right side of the module can automatically receive, and restore the
original left device from the TXD UART data send. From right to left is the same. Module can
only work in half duplex state, can not send and receive data at the same time.
⑵ UART transparent transmission characteristics
HC-12 module has four UART transparent transmission mode: FU1, FU2, FU3 and FU4.
When in use, various modes are just to send and receive UART data can be, without air wireless
transmission part, but only in the same air baud rate can communicate with each other under the
sky! The system default in FU3 full speed mode, this mode can automatically adjust the air
according to the baud rate of serial baud rate, low baud rate communication distance.
Different mode can not transmission data each other, the user can choose the best mode
according to the actual situation.
Modules are generally used in pairs to transmit data to each other in half duplex mode. At
the same time, the transparent transmission mode, the baud rate, the wireless communication
channels must be set the same. Factory default is set to FU3, 9600bps (8 bits data, no parity, 1
stop bit), CH001 (433.4MHz).
The number of bytes send to the module UART port is generally not limited in use. But in
view of the environmental interference and other factors, a continuous transmission of a large
number of data, it is possible to lose some of the bytes. So, it is best to have a answer response
and retransmission mechanism, to avoid the loss of information.