Railway real-time HDLC network card based on dual-port RAM

Abstract

The invention discloses a railway real-time HDLC network card based on a dual-port RAM. The railway real-time HDLC network card comprises six RS485 interfaces, two HDLC interfaces, a main control module, a UART extension module, an HDLC encoding and decoding module and a dual-port RAM module. The main control module is respectively connected with the UART extension module, the HDLC coding and decoding module and the dual-port RAM module; and the HDLC network card is used for realizing data transmission between the vehicle-mounted equipment main controller (MCU) and the train communication network (TMS) according to an HDLC protocol. According to the embodiment of the invention, hardware HDLC protocol coding and decoding are independent of MCU operation, and the MCU and the network card exchange data through the shared multi-port memory dual-port RAM, so that the network structure of the MCU is optimized, and the requirement of railway HDLC data transmission on real-time performance is met.

Description

technical field [0001] The invention relates to the technical field of rail transit vehicles and railway trains, in particular to a dual-port RAM-based railway real-time HDLC network card. Background technique [0002] With the development of the rail transit and railway industry, due to the specialization and strong pertinence of the railway communication network, the network cards used to convert the HDLC (High-Level Data Link Control or HDLC for short) protocol into other data forms are mostly real-time Poor serial interface, such as HDLC conversion to UART and other data forms. The existing data conversion form mainly depends on the private serial protocol defined by each manufacturer. If the existing system needs to replace another network card, the driver code including the host and its link needs to be rewritten to realize the function of controlling network card communication. In addition, the serial link using the software protocol has poor real-time performance, w...

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Problems solved by technology

In addition, the real-time performance of the serial link using the software protocol is poor, which cannot better meet the real-time requirements of the railway HDLC data communication network

[0003] However, the existing HDLC protocol interface scheme is directly realized by the MCU, which needs to add a peripheral physical layer HDLC protocol control chip, because the MCU not only needs to realize the HDLC function, but also needs to control other functions of the vehicle, such as HDLC data. Conversion, sending and receiving control, etc. occupy a large amount of MCU resources, resulting in increased memory costs, and the real-time performance of the software protocol stack is poor, and it cannot better meet the real-time requirements of the railway HDLC data communication network

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