Matthias Dörfel

Hardware/software codesign and rapid prototyping of embedded systems

The complexity and the short time to market of embedded systems require the use of automated techniques during the specification, implementation, and testing phases of such systems. Due to the cost requirements and the timing constraints of such systems, application-specific hardware solutions are often needed, making the codesign of hardware and software a major topic for the design automation of embedded systems. This article describes tools for the analysis, synthesis, and rapid prototyping of distributed embedded real-time systems and presents a complete design flow from specification to implementation.

Generating mixing hardware/software systems from SDL specifications

A new approach for the translation of SDL specifications to a mixed hardware/software system is presented. Based on the computational model of communicating extended finite state machines (EFSM) the control flow is separated from data flow of the SDL process. Hence for the first time it is possible to generate a mixed hardware/software implementation of an SDL process. This technique also reduces the complexity for high-level and register-transfer synthesis tools for the hardware parts of the system. The advantage of this methodology is shown by a design example of a wireless communication chip.

A General Approach for the Specification of Real-Time Systems with SDL

In contrast to protocols of the network or transport layer the protocols for medium access have to consider the timing behavior of the communication medium. Although SDL is a widely used language for the specification of communication systems, in most cases time critical parts are not considered. In this paper, a design pattern is discussed that allows the specification of time critical functionality sucg as multiplexers or Quality-of-Service (QoS) schedulers. In many applications such services are running in a synchronous manner with the communication medium. A notation for timing aspects is needed for the specification of this behavior which itself is only possible in a sensible way with a formal model of time. Clocks are used to define the term real-time in a formal way, leading to the specification of timing constraints, for example sending data packets in deterministic time intervals within a communication system. In a case study from the mobile communication area, the design pattern was used to specify the MAC-Layer including time critical parts.

A prototyping system for high performance communication systems

Presents a prototyping platform for high-performance communication systems together with a design methodology. Based on a formal design entry and nonfunctional design goals such as execution time and overall system cost, a software/hardware partitioning is generated and its performance is estimated with formal models. Valid partitionings are then implemented on a prototyping platform which is based on a heterogeneous multiprocessor system and a reconfigurable FPGA board. Using model-based optimization and monitoring, each partitioning is evaluated and the results are fed back in the generation and estimation of new partitionings.

A general time model for the specification and design of embedded real-time systems

Design of complex embedded systems feasible with current and upcoming semiconductor technologies necessitates consideration of real-time from the beginning. However, the commonly used specification techniques do not consider temporal aspects in general like fulfillment of high level timing requirements or dynamic reactions on timing violations. In this paper, we discuss the restrictions of current specification techniques for embedded real-time systems and present a general time model that solves this issue. The time model contains the progress of time, the measurement of time and the specification of timing requirements based on event traces. In contrast to earlier techniques, preconditions determine the actual relevance of a specific timing bound. Exemplified for SDL, a solution for the specification of temporal aspects is shown. The advantages of this solution are discussed in a hardware/software co-design case study from the mobile communication area.

A scalable hardware library for the rapid prototyping of SDL specifications

A known problem in the area of hardware/software codesign is the selection of the proper interface between the different parts of the design. This paper presents a technique which eases the selection by combining different synthesis techniques together with rapid prototyping. The application field of the technique is the design of communication systems where C and VHDL are generated from a specification given in SDL. For the VHDL area, high-level synthesis is used to synthesize a behavioural description.

A New Time Model for the Specification, Design, Validation and Synthesis of Embedded Real-Time Systems

Summary form only given. An essential characteristic of embedded systems is real-time, but the commonly used specification techniques do not consider temporal aspects in general like fulfilment of high level timing requirements or dynamic reactions on timing violations. We show a new formal time model that fills this gap: timing requirements specify the timing behaviour of real-time systems. Different models allow the specification of clock properties and the relations between clocks. With this time model, timing requirements as well as the desired properties of the involved clocks can be specified within a formal description technique.

CORSAIR: HW/SW-Codesign von Kommunikationssystemen mit SDL

ZUSAMMENFASSUNG Der Artikel beschreibt die CORSAIR-Umgebung (Codesign and Rapid Prototyping System for Applications with Realtime Constraints) zum Entwurf und zur Implementierung von Kommunikationssystemen auf der Basis der formalen Beschreibungstechnik SDL. Im Unterschied zu gängigen SDL-Werkzeugen zielt das Projekt auf die Entwicklung gemischter HW/SW-Systeme anstatt reiner Softwareimplementierungen. Weitere Besonderheit unseres Ansatzes ist die durchgängige Berücksichtigung von Zeitanforderungen in allen Phasen des Entwicklungsprozesses. Unser Ansatz basiert auf einer Erweiterung von SDL, die die Beschreibung von Zeit- und Implementierungsaspekten unterstützt. CORSAIR zielt auf die weitgehende Automatisierung des Entwicklungsprozesses, entsprechend dem HW/SW-Codesign-Prinzip. HW/SW-Codesign unterstützt die späte und damit flexible Partitionierung der Spezifikation in Teile, die in Hardware bzw. in Software implementiert werden.