Đang chuẩn bị liên kết để tải về tài liệu:
Model-Based Design for Embedded Systems- Part 13

Không đóng trình duyệt đến khi xuất hiện nút TẢI XUỐNG Tải xuống

Model-Based Design for Embedded Systems- P13: This book contains information obtained from authentic and highly regarded sources. Reasonable efforts have been made to publish reliable data and information, but the author and publisher cannot assume responsibility for the validity of all materials or the consequences of their use. | 86 Model-Based Design for Embedded Systems messages that can arrive at ECU1. Using flat event models we could only assume that every message contains a new signal for both receiving tasks which results in a load of 91.58 of ECU1. With the HEM we also obtain the maximum number of messages that contain a signal that was sent by task ctrll marked by squares and the maximum number of messages containing a signal from ctrl2 marked by triangles . If we now use the timings of signal arrivals as activation timings of the receiving tasks we obtain a much smaller load of only 45 for ECU1. Hence the system is not only schedulable but it also appears that the bus with less than 50 utilization still has sufficient reserves to accommodate the additional communication of the parking-assistant application. Especially since the time the parking assistant is enabled the ESP communication is disabled. 3.8.2 Analyzing Scenario 2 In Scenario 2 Sensors 1 and 2 are disabled and therefore tasks mon1 and mon2 are never activated. Consequently they will not send data to the tasks eval1 and eval2. The control tasks ctrl1 and ctrl2 are still executed and send their data to the execution tasks running on ECU1. Their local response times will slightly decrease as there will now be no competition for the shared memory from the second core. On the CAN bus we have the two additional communication tasks C3 and C4 representing the communication of the parking-assistant application. When we analyze this system we obtain a maximum latency of 22 ms for the path IP1 IP2 and 131 ms for the path Sens3 SigOut. Therefore the system is also schedulable when only the parking-assistant application is running. 3.8.3 Considering Scenario Change Having analyzed the two scenarios in isolation from each other we neglected the recurrent transient overload that may occur during the SC. This may lead to optimistic analysis results. Thus the SC analysis is needed to verify the timing constraints across the SC. In the .