Design And Realization Of OSEK Real-time Operating System Based On μC/OS-Ⅱ For Automobile Control

With the automobile function multipling,the number of electronic control cell on per automobile is on the average of 50.So the automobile software system becomes more complex and the applications development is also more difficult than before.In order to reduce the difficulty of applications development,the European automobile industry collaboratively put forward the open systems and the corresponding interfaces standard for automotive electronics(OSEK/VDX standard)in the beginning of 1990s.The standard is much more important on the applications development,it can shield the difference among various electronic control cell and supply the corresponding interface to software user.By using the OSEK/VDX standard,the cost and time of applications development are obviously decreased.In this paper,first,OSEK/VDX standard is introduced and the operating system(OS) standard is researched on emphases.Second,the principle of theμC/OS-Ⅱreal-time operating system is analysed and compared with the OS running mechanism.Based on the result after comparing,theμC/OS-Ⅱkernel is ameliorated to accord with the OSEK/VDX standard and supply an open software development system for programmers.The main contents in the code amelioration module can be summarized as the following three aspects:1.A new task ready table is created forμC/OS-Ⅱkernel.Improving on the algorithm of searching the highest priority in the new table can change the priority sequence;improving on the algorithm of mading task in ready can increase the priority number.2.Priority ceiling principle(pcp) is introduced into theμC/OS-Ⅱkernel when the priority reversion appears,the pcp can take order with the exigency in automobile control.3.According to the introduction of alarm service in OSEK/VDX standard,in μC/OS-Ⅱkernel an alarm module is added which uses counter to calculate the time limit.If the counter achieves the threshold which is set by alarm,the alarm service will be executed.Before code amelioration,theμC/OS-Ⅱis replanted to the MC9S12DP256B singlechip for supplying the experimentation to test the operating system while ameliorating and performing.Focus on the above three work points,writing testing programme to verify the operating system and the test results show that it is ok.