Monitor Diagnostic Equipment Hardware Platform And Network Interface Unit Design, Based On The Obd-ii Vehicle Failure

With the development of electric technology and control technology, special fault diagnostic tools are used in automobile's fault diagnosis. Now, the on broad diagnostic system can monitor the systemic parameters of automotive electronic control system continuously. This kind of diagnostic system can memorize the intermittent problems. So it would be easier and faster to find out the faults. The communication protocols used by diagnostic system, the communication criterions which shoud be followed, and the trouble codes and how to get them are described in detail in OBD-â…¡standard. Most of the automobile manufactures have adopted the OBD-â…¡fault diagnostic system.The on-vehicle fault diagnostic platform is used to get diagnostic information and real-time status messages from the electronic control units. It communicates with the electronic control units through the OBD-â…¡electrical connector, acquire trouble codes and datas. The diagnostic results will be displayed on the LCD.This dissertation based on in-depth study of the protocols and methods which defined by OBD-â…¡standard. It puts forward how to design the on-vehicle fault diagnostic platform.The fault diagnostic cell is responsible to get and analyse the trouble codes. The hardware core is S3C2410, the peripherally auxiliary circuit design is carried out in this dissertation. The sofeware framework also carried out in this dissertation.The interface cell of the on-vehicle fault diagnostic platform is the gateway between the automobile and the diagnostic equipment. It convertes the code schemes between OBD-â…¡and RS232. Two different methods for interface cell design are presented in this dissertation. One bases on the microcontroller and the other bases on the ASIC special for protocol converting. Some design works, such as the hardware and software design in both methods are carried out in this dissertation.