Features, the human-machine interface part is designed as follows: color LCD display: ETX embedded CPU module can directly support CRT display and flat panel display (FlatPanel), in this system, choose Siemens matrix color LCD% but due to ETX module The LCD interface is LVDS mode, and the input interface of the selected LCD is TTL mode, so the conversion circuit is required for conversion.
Voice prompt: In order to avoid distracting the driver's attention by watching the display screen, causing inconvenience in driving and traffic safety, the speech synthesis module is used to output the navigation information, which makes the navigation device more humanized. The speech synthesis chip is a Chinese speech synthesis chip of Zhongke Daxun Information Technology Co., Ltd. It is connected with COM2 of ETX, and receives the text to be synthesized through the asynchronous serial port, and directly synthesizes it into voice output.
Keyboard and infrared remote control: In order to facilitate the driver to manipulate the positioning navigation system, a matrix keyboard is designed to control the cursor selection menu and modify the driving destination. The matrix keyboard output signal is converted to a standard keyboard interface signal by a single-chip microcomputer and connected to the ETX. At the same time, an infrared remote control receiving device is designed to facilitate the remote operation of the driver or passenger when the keyboard is inconvenient to use. The decoding of the infrared signal is also performed by the same microcontroller and converted into a standard keyboard signal.
The car GPS navigation system requires a large amount of data storage space for electronic maps, vehicle trajectory data and other information storage, and because the vehicle environment is relatively harsh, especially the vibration is severe, the ordinary hard disk is difficult to handle the storage tasks of the system. Since ETX provides two EIDE interfaces, a CF card that can be directly connected to the EIDE interface is selected as the storage device, and the capacity can be selected according to the size of the electronic map database. For entertainment purposes, you can connect to the EIDE interface CD-ROM drive.
In order to connect with other in-vehicle devices, a certain number of serial ports are required, and ETX itself only provides two serial ports, so it needs to be expanded. The serial port expansion can be performed using the ISA bus provided by ETX, as shown.
Nowadays, more and more in-vehicle devices use the CAN bus, and the interfaces with these devices can be extended by using the PCI bus provided by ETX, as shown.
ETX provides USB1.1 interface and network port, which can be used according to actual needs.
See, you can expand according to actual needs.
2.2 Software Design Because ETX is completely compatible with PC and has enough memory, all PC-based operating systems and navigation system applications developed on them can be easily transplanted on our system. The real-time embedded operating system VxBo "ks and the navigation system application software developed on it are used. The software is divided into drivers and applications.
The driver is mainly VxWo "BSP (board support package) under ks, because we are using ETP based on IntelPentiumI processor, so you can modify it according to the actual situation on the template provided by VxBo"ks. The driver of the serial port extension part and the CAN bus driver extended by the PCI can also be modified according to the serial port driver template and the PCI driver template.
The application program is mainly focused on the development and management of electronic navigation maps, as well as map matching and positioning information display. It is divided into the following parts: System main control module: responsible for coordinating the operation of each functional module, achieving each Monitoring of module tasks, and is responsible for providing an interactive interface with the driver and displaying system related information; communication module: responsible for completing communication between various parts of the system; positioning module: responsible for completing positioning data processing, coordinate conversion, navigation Function provides necessary information; electronic map: This module is the core part of the application software, completes the functions of electronic map database management, map display, etc.; navigation module: responsible for completing real-time tracking of vehicles, path recording and playback, voice navigation, etc. .
3 Conclusion It can be seen that ETX has unique advantages in the application of car GPS navigation system. The above-designed ETX-based car GPS navigation system makes full use of the characteristics of ETX, and has the characteristics of simple, reliable, practical, low power consumption and powerful functions, and has been successfully applied to a certain vehicle project.
Taiyuan uses SMS to monitor street lighting technology Recently, Taiyuan City has added a new landscape light monitoring function, which is in a leading position in the country. This function is controlled by SMS. Enter a new SIM card number into the electronic module in the power distribution cabinet, and then input the SMS command to make the contactor of the power distribution cabinet pull or release to control the street light to turn off or off. Similarly, you can use this function to view the voltage and current of the street light, set the alarm call command, and check the switch time.
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