The method of simulating multi-channel full-duplex serial ports under the arm platform linux system

Abstract

The invention provides a method for simulating a multi-circuit dual-full-duplex serial port under an ARM (advanced RISC machine) platform LINUX system. The method is characterized in that by establishing an interrupt environment and initializing a simulated serial port interface, the communication of a simulated serial port can utilize FIQ (fast interruption quest) interrupt to receive and transmit the data, a non-maskable property for the LINUX system can be achieved, the high real-time property can be realized, and the error code problem can be basically prevented under the situation that the appropriate frequency is provided. The entire scheme is established according to a UART (universal asynchronous receiver / transmitter) drive framework under the LINUX system, so that the interface uniformity under the LINUX system can be guaranteed, the simulated serial port is identical to an interface of an ordinary serial port in use, a receiving baud rate and a transmitting baud rate can be respectively arranged, the full fuplex is received and transmitted, convenience can be realized; and only one hardware timer is used on the aspect of the hardware resource, only two ordinary GPIO (general purpose input / output) ports are added for adding multiple serial ports, no additional resource is needed, and the expandability is strong.

Description

technical field [0001] The invention relates to the application field of the LINUX system under the ARM platform, in particular to a method for simulating multi-channel full-duplex serial ports under the ARM platform LINUX system. Background technique [0002] At present, due to ARM's low power consumption, high performance, easy expansion, and LINUX's open source and free, the ARM+LINUX platform has become the hottest supporting platform in the embedded field. Although the ARM platform itself has abundant peripherals, but in some In some cases, when more serial ports are needed to communicate with various peripherals, the number of serial ports is still not enough. There are usually two ways to resolve this situation, [0003] 1. Increase the serial port by extending the chip, but there is no doubt that the chip will increase the cost of the product; 2. Simulate the serial port by directly using the ordinary interrupt (IRQ). This method is simple, direct, and easy to imple...

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Problems solved by technology

[0003] 1. Increase the serial port by extending the chip, but there is no doubt that the chip will increase the cost of the product; 2. Simulate the serial port by directly using the ordinary interrupt (IRQ). This method is simple, direct, and easy to implement, but the disadvantages are also obvious. Because the entire system scheduling and mutual exclusion of LINUX use the IRQ interrupt mode, the method of closing IRQ to achieve mutual exclusion during system operation can be seen everywhere, which directly leads to the low efficiency of the simulated serial port realized by this method, high bit error rate, The baud rate can't go up, let alone simulate multiple serial ports

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