Preemptive multiplexed serial port automatic switching method and device

Abstract

The invention discloses a preemptive multiplexed serial port automatic switching method and device. The method comprises the steps of setting an input output end of an MCU chip in equipment as a flagbit, connecting the input output end with a power supply through a second resistor and leading out a first suspended end; connecting a serial port data input end of the MCU chip with a serial port data output end of a sensor in the equipment and a second suspended end through a first diode and a second diode respectively, and connecting positive electrodes of the first diode and the second diodewith the serial port data input end of the MCU chip; connecting the serial port data input end of the MCU chip with the power supply through a first resistor; and connecting a serial port data outputend of the MCU chip with a serial port data input end of the sensor. After the external serial port equipment is manually inserted, communication can be automatically performed with the inserted equipment, so that a channel automatic switching function is realized; and after the external serial port equipment is pulled out, communication is performed with the sensor again, so that a preemptive multiplexed serial port automatic switching function is realized.

Description

technical field [0001] The invention relates to the technical field of serial port communication, in particular to a method and device for automatic switching of preemptive multiplexed serial ports. Background technique [0002] In the single board of communication equipment, the serial interface is the most commonly used human-computer interaction interface. However, the number of serial ports of the MCU chip in some equipment single boards is currently limited. Usually, these serial ports communicate with the sensors inside the device (serial communication mode), and are used When it is used up, the serial port can no longer be used to communicate with external serial devices, so it is also impossible to perform local upgrades, serial port online debugging, or connect to the serial port screen for parameter setting and other operations through the serial port. [0003] At present, there are mainly the following types to solve the above problems: 1. Expand the required seri...

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Problems solved by technology

[0002] In the single board of communication equipment, the serial interface is the most commonly used human-computer interaction interface. However, the number of serial ports of the MCU chip in some equipment single boards is currently limited. Usually, these serial ports communicate with the sensors inside the device (serial communication mode), and are used When it is used up, the serial port can no longer be used to communicate with external serial devices, so it is also impossible to perform local upgrades, serial port online debugging, or connect to the serial port screen for parameter setting and other operations through the serial port.

[0003] At present, there are mainly the following ways to solve the above problems: 1. Expand the required serial port with a serial port expansion chip or MCU. The disadvantage of this method is to increase the hardware cost and the complexity of the software; 2. Add jumper caps or The switching method is to manually switch between the serial port of the MCU chip and the sensor and the external serial port. Although this method is simple, it is very inconvenient to maintain. It is difficult for users to distinguish which serial port to use for connection. The reliability is poor, and the device must be restarted when the external serial device is connected (the communication protocol between the MCU chip and the external serial device and the internal serial communication must be different)

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