The Design Of The Remote Vehicle Mobile Communication Interface

With the development of times, wireless data communication and GPRS have worked as a great help for improving automotive safety and comfort. Telematics is the combination of telecommunication andinformatics, supplying drivers and passengers many services, one of which is remote fault diagnosis.There are artificial diagnosis, device diagnosis and on-board diagnosis for automotive fault diagnosis. The first two methods require much knowledge and experience and the last method is restricted by ECU's Computing speed. Compared to the traditional ways, the remote fault diagnosis uses internet, blue-tooth, GSM and GPRS to diagnose the vehicle. The remote fault diagnosis will bring changes: vehicles can diagnose itself during travelling; drivers can check the problem more quickly, which will increase the automotive safety and reduce the maintenance cost.GPRS network uses the Internet Protocolforpacket switching with the Internet, so ECU can be accessed from PC on the Internet. SAE J2534 for reprogramming ECU is used as a implementation of the system. Freescale S12 MCU works as the core part of the terminal on vehicle which has CAN, J1850 VPW and K Line controller. When the terminal build a link with the ECU, PC would request or clear the DTC in ECU. GPRS module with TCP/IP stack is used to link the terminal and Internet which simplifies software development. This article designs the software and hardware according to the functions. The hardware design is based on Protel 99SE, which has four stages: component selection, schematic design, PCB design and testing. The hardware is composed of the smallest single-chip system, bus communication module and wireless communication. In addition, the application layers communicate based on a custom agreement. The agreement is developped using visual studio 2008 and packeted into DLL.In the testing process, the application can get required data from the bus correctly after relevant parameters are configured, which could verifies the accuracy of the design preliminarily. The system is easy to operate and develop new features, which means it can be modified a little to collect and monitioring vehicle CAN bus data.