The LED screen on the subway is divided into two types.
The utility model is disposed on the outer side of the compartment for displaying the train running section, the running direction and the current station name, and is compatible with the Chinese and English display; the other service information may also be displayed according to the operation requirement; the text display may select static, scrolling, panning, waterfall, Various effects such as animation, the maximum number of characters displayed is 16 × 16 dot matrix characters. The other is the terminal LED display, which is placed in the car. The terminal LED display can preset the terminal according to the train operation requirements, and display the current terminal in real time. It can also display the current interior temperature and the maximum number of displayed characters. 8 characters for 16 × 16 dot matrix.
The LED display system screen consists of two parts: the MCU control unit and the display unit.
A single display unit can display 4 × 16 Chinese characters. If a certain size LED display system is produced, as long as several intelligent display units are used, the method of “building blocks†can be realized, and each display unit in the system can be realized. Serial communication is used. In addition to controlling the display unit and transmitting the commands and signals of the upper computer, the control unit also embeds a single bus digital temperature sensor 18B20. Thanks to the modular design of the control circuit, the 18b20 can be upgraded to a modular circuit consisting of Dallas DS2438 and HoneywELl's HIH23610, if required for humidity measurement. In order to meet the communication needs of the whole vehicle, the host computer communicates with each control unit in the vehicle by CAN bus.
The display unit is composed of two parts: an LED display panel and a display circuit.
LED display panel is a 16 × 64 dot matrix universal intelligent display unit consisting of 4 dot matrix modules. A single display unit can display 4 16 × 16 dot matrix Chinese characters or symbols in full screen. Serial communication is used between display units in the system. Contact, so that the work of the entire system is coordinated. The display circuit consists of two 16-pin cable ports, two 74H245 three-state bus drivers, one 74HC04D six-inverter, two 74H138 eight decoders, and eight 74HC595 shift latches. The core of the control circuit is WINBOND's high-speed single-chip microcomputer 77E58, the crystal frequency is 24 MHz. A T29C020A is 256 K ROM, which is used to store 16 × 16 dot matrix Chinese character library and 16 × 8 dot matrix ASCII code table. A T24C020 is an EP2ROM based on the I2C serial bus, which stores pre-defined statements such as subway station names, greetings, and so on. The interior temperature is measured by a single-bus digital temperature sensor 18b20. The SJA1000 and TJA1040 are CAN bus controllers and transceivers, respectively.
Edit: Cedar
Xinxiang Mina Import & Export Co., Ltd. , https://www.mina-motor.cn