The Development Of Graphical Automotive Instrument Based On QNX Operating System

With the TFT-LCD screen replacing the traditional mechanical structure on theinstruments, full-blown graphical dashboard solve the requirements of contents andexpansibility, began to be applied in the high-end models gradually. The domesticdevelopment is still in the experimental stage, general-purpose processor and opensource embedded operate system are not suitable for the application environment ofautomotive instrument. Compared to consumer electronics, automotive electronics has ahigher demand of reliability and security. As a kind of micro-kernel real time operatesystem, QNX has a clear structure, stability function and high reliability. This paperpresents a development program of full-blown graphical dashboard based on the QNXsystem.On the QNX microkernel structure, each process runs in a separate address spaceand avoids system crashes due to application problem. Preemptive scheduling and fastcontext switching guarantee real-time. Based on message passing, QNX provides avariety of interprocess communicate.Based on the structure of QNX, the instrument software is designed hierarchically.Drivers interact with the underlying hardware and provide a unified interface forapplications in the structure of the QNX; applications use standard communication andcall, to improve the portability of the system; the modules are divided and each moduleuses the structure of multi-threads. The combination of RR and FIFO is set as thescheduling policy.Resourse manger provides a standard interface for drivers, and it is convinent fortransplantation of application progressed. The architecture and work way are analysised.The driver of CAN controller is developed in the way of resourse manger. The bootpeocess of QNX is analysised and package the instrument softeware in system image.Analysis the display needs of vehicle information, divided display types intopersistent display, dynamic display, digital display and easing show, display solution ofeach type under QNX.The drawing of instrument interface on the flash developmentenvironment is more convenient and intuitive. The structure is clearer usingActionScript for dynamic control of the graphics. According to the moving of pointers,two programs are proposed, the class file of actionscript and OpenGL. The effects arecompared in the final.