Implementation method of serial port multiplexer with transmission priority

The invention discloses an implementation method of a serial port multiplexer with the transmission priority. The method is able to multiplex a plurality of serial port (named extended serial port) data to a serial port (named main serial port) to transmit. The method comprises the following steps: distinguishing all extended serial ports by a mode of adding a frame head and a frame end; setting one of the extended serial ports as the extended serial port with high transmission priority, or setting all extended serial ports into the extended serial ports with low transmission priority; performing data transmission for the extended serial ports at high transmission priority through the main serial port preferentially, wherein each extended serial port is equipped with a receiving data cache area and a sending data cache area which are used for caching serial port data; a single-chip microcomputer is used for controlling time-division transmission of data within each cache area. With the adoption of the method, the problem of small serial port sources of a device in the actual application is solved, the transmission priority of the extended serial port can be set at the same time, and the delay of data transmission of the serial ports at high transmission priority is minimized. The method has the advantages of being fast in communication rate, small in error rate, flexible to configure, simple, practical, and small in cost.