This paper discusses a model-based design flow for requirements in distributed embedded software development. Such requirements are specified using a language similar to linear temporal logic which allows one to reason about time and sequencing. They consist of assertions which must hold for a design, given some assumptions on its environment. They can be checked both during simulation and, at least for a subset, even on the target. The key contribution of the paper is the extension to the embedded software domain of assertion-based verification, and the automated generation of property-checking code in multiple target languages, from simulation, to prototyping, to final production.

Summary form only given.The concept of virtual integration platform plays a key role in any novel methodology that is trying to address earlier validation of distributed applications in regular and faulty conditions. The methodology must rely upon libraries that model the most important features of the commonly used IP's in the automotive segment such as FlexRay, the emerging bus protocol for safety critical applications supported by BMW, Daimler-Chrysler, Philips, Bosch, and Motorola, OSEK compliant RTOSes and protocol stacks, microprocessors such as Motoro/IBM PowerPC, Infineon 167, NEC v850, Tricore, ST 10, and Janus. We believe that tools must support the easy plug and play of the IP models in a seamless way to the user. For example, it must be possible to run a fast simulation at the token level (frames) to provide insights about the best network protocol configuration within a reasonable accuracy for the estimated frame latency. Next, it must be possible to export such a configuration to (semi)-automatically configure the downstream and more refined bus protocol models for the finer grain validation step. Both steps must rely upon interchangeable IP's with clear interfaces and trade-offs between simulation speed and accuracy of the timing estimates. In this paper, we present two examples of models of IP's that can be used at two different steps in the design exploration, the token-level/cycle approximate transaction based level and the cycle accurate level. The first example is the Universal Communication Model (UCM) that captures the main common features of the most relevant bus protocols such as topology, redundancy, arbitration, etc. The model enables quick token-level simulations. The user is able to determine the communication cycle layout and bus scheduling, k-matrix, and then export it for the configuration of downstream more refined models such as the Motorola FlexRay cycle accurate transaction based model. Bus delays are as important as task execution delays and RTOS switching overheads. In the second example we introduce Janus, a multi-processor micro-controller for power train applications. The cycle approximate transaction based model of Janus can be used to assess the ECU HW/SW partitioning, in particular to quickly explore different task scheduling and allocation. Then, this model is refined and exported to configure a HW/SW co-verification tool for the cycle accurate validation of the ECU HW/SW architecture. In an example scenario, an engine control ECU is providing information about the engine (e.g. engine revolution speed) to a gear control ECU over a CAN bus (the latter typically requires precise revolution speed to operate and could also require to set the engine operation condition). In this scenario, car and subsystem makers play different roles in order to provide a virtual model of the system to validate the functionality and the performance before going to implementation. The same models can then be used to march toward implementation.

In this paper, we present the new concept of virtual integration platform for automotive electronics. The platform provides the basis for a novel methodology in which the integration of sub-systems is performed much earlier in the design cycle. As a result, cost reduction in the final implementation and in the design process can be achieved. In addition, early and repeatable fault analysis can be performed therefore easing the task of system safety proving.

The Fsprit/OMI-COSY project defines transaction-levels to set-up the exchange of IP's in separating function from architecture and body-behavior from proprietary interfaces. These transaction-levels are supported by the “COSY COMMUNICATION IPs” that are presented in this paper. They implement onto Systems-On-Chip the extended Kahn Process Network that is defined in COSY for modeling signal processing applications. We present a generic implementation and performance model of these system-level communications and we illustrate specific implementations. They set system communications across software and hardware boundaries, and achieve bus independence through the Virtual Component Interface of the VSI Alliance. Finally, we describe the COSY-VCC flow that supports communication refinement from specification, to performance estimation, to implementation.

We present a programming interface called YAPI to model signal processing applications as process networks. The purpose of YAPI is to enable the reuse of signal processing applications and the mapping of signal processing applications onto heterogeneous systems that contain hardware and software components. To this end, YAPI separates the concerns of the application programmer, who determines the functionality of the system, and the system designer, who determines the implementation of the functionality. The proposed model of computation extends the existing model of Kahn process networks with channel selection to support non-deterministic events. We provide an efficient implementation of YAPI in the form of a C++ run-time library to execute the applications on a workstation. Subsequently, the applications are used by the system designer as input for mapping and performance analysis in the design of complex signal processing systems. We evaluate this methodology on the design of a digital video broadcast system-on-chip.

A quantitative method for designing application specific integrated (sub)systems is presented. The method uses a general-purpose silicon assembler-ALMA (Approche d'un Langage de Micro-Architecture). We illustrate this approach by the example of a dictionary machine that consists of n processing elements working in parallel. An analysis of the effect of several generic parameters on the performance and the size of the silicon parts exemplifies the quantitative approach to cost/performance tradeoffs that is offered by ALMA.>

ALMA presents itself like a shell over a CAD framework. It mainly aims at portable description (independent on CAD framework); rapid system modelling (using a powerful temporal and functional simulator), and quick realization (using a sequential language manipulating hardware resources like registers, ALUs). The ALMA strongest point is its practical side. It offers entry points within the system at two different levels. The first level gives the possibility to install new resources in the input language. Except on installation phases for these new resources, this level is a portable entry. The second level is to directly bring into the simulator manually designed blocks by describing their models. Such a feature is of course not portable. Finally, ALMA relations to CAD frameworks look a little bit like Unix relations to computers. ALMA is a general purpose kernel, but this kernel is open, and the user can focus itself onto a specific application domain.>