6 Conclusion

We have shown, how a schedulability analysis, including a codesign approach for periodic tasks, can be extended for the analysis of sporadic tasks and dependencies between tasks, what often occurs in SDL/MSC specified systems. To allow this we extended the classical task model with starting points for each task. To calculate the response times of sporadic tasks we consider instances of tasks. The using of task instances has the disadvantage that the analysis needs more computation time than the classical approach with periodic tasks. Because the algorithm allows to calculate worst-case response times of tasks which are running on heterogeneous architectures, and the task interaction for different use-case-scenarios can be specified by MSCs, the described algorithm is potentially a powerful evaluation algorithm for a system synthesis tool for SDL/MSC specified systems. 7 References [1] J.Axelsson. Hardware/software partitioning aiming a fulfilment of real-time constraints. programmable on the BMC. The SLI will be supported by an independent task in our task model (see table 1). The DLC and the MAC layers are implementing the higher part of layer 2 of the OSI protocol stack. The lower part of layer two is realized by the BMC controller and the layer one is implemented by the radio module of the portable part. 5.3 Performance Analysis of the Mobile Part All software-tasks of the system are running on a 8051 microcontroller (note that in this case I(τ, τ') = C(τ')). If the telephone receives data, the task RV (Receive) which runs on the BMC writes the data to the registers of the BMC. Then the burst-mode logic interrupts the microcon-troller. In dependence from the logical channel, the controller starts an interrupt service routine (ISR). The ISR has an interference I(RV, ISR) = 0.1 with the hardware task, because both tasks are using the registers of the BMC. The ISR copies the data from the registers of the ASIC to the microcontroller's memory. In table 1 it is shown how the algorithm analyzes the receipt of a network layer (NWK) message. First the ISR calls six times the MAC and the DLC. After the DLC received six fragments of the NWK layer message, the DLC calls the NWK layer. In table 1 we show the analysis results after the receiving of the sixth messages. The communication between the tasks is marked by a backslash at the starting point. This means that a task is triggered by …