System level design is considered a major approach to tackle the complexity of modern System-on-Chip designs. Embedded software within SoCs is gaining importance as it addresses the increasing need for flexible and feature-rich solutions. Therefore, integrating software design and co-simulation into a system level design flow is highly desirable. In this article, we present the software perspective within our system-level design flow. We address three major aspects: (1) modeling of a processor (from abstract to ISS-based), (2) porting of an RTOS, and (3) the embedded software generation including RTOS targeting. We describe these aspects based on a case study for the ARM7TDMI processor. We show processor models including a cycle-accurate ISS-based model (using SWARM), which executes the RTOS MicroC/OS-II. We demonstrate our flow with an automotive application of anti-lock breaks using one ECU and CAN-connected sensors. Our experimental results show that automatic SW generation is achievable and that SW designers can utilize the system level benefits. This allows the designer to develop applications more efficiently at the abstract system level.