Carlos Valderrama

A unified model for co-simulation and co-synthesis of mixed hardware/software systems

This paper presents a methodology for a unified co-simulation and co-synthesis of hardware-software systems. This approach addresses the modeling of communication between the hardware and software modules at different abstraction levels and for different design tools. The main contribution is the use of a multi-view library concept in order to hide specific hardware/software implementation details and communication schemes. A system is viewed as a set of communicating hardware (VHDL) and software (C) sub-systems. The same C, VHDL descriptions can be used for both co-simulation and hardware-software co-synthesis. This approach is illustrated by an example.<<ETX>>

A Multi-Resolution FPGA-Based Architecture for Real-Time Edge and Corner Detection

This work presents a new flexible parameterizable architecture for image and video processing with reduced latency and memory requirements, supporting a variable input resolution. The proposed architecture is optimized for feature detection, more specifically, the Canny edge detector and the Harris corner detector. The architecture contains neighborhood extractors and threshold operators that can be parameterized at runtime. Also, algorithm simplifications are employed to reduce mathematical complexity, memory requirements, and latency without losing reliability. Furthermore, we present the proposed architecture implementation on an FPGA-based platform and its analogous optimized implementation on a GPU-based architecture for comparison. A performance analysis of the FPGA and the GPU implementations, and an extra CPU reference implementation, shows the competitive throughput of the proposed architecture even at a much lower clock frequency than those of the GPU and the CPU. Also, the results show a clear advantage of the proposed architecture in terms of power consumption and maintain a reliable performance with noisy images, low latency and memory requirements.

Automatic generation of interfaces for distributed C-VHDL cosimulation of embedded systems: an industrial experience

This paper presents a distributed hardware/software cosimulation environment for heterogeneous systems prototyping applied to an industrial application. The environment provides following features: distributed Hw/Sw cosimulation, automatic Hw/Sw interface generation, Hw elements can be described at different levels of abstraction and generic/specific Sw debuggers can be used. Starting from a brief description of the interface of the interconnected modules the tool automatically produces the link between Hw and Sw parts. In addition, the environment is very easy to use, even for complex systems that may include several Sw (C) modules and several Hw (VHDL) modules running in parallel. Applied to a large industrial multi-processor system, this method appeared reliable and efficient, providing important benefits in hardware-software codesign: better design environment and reduced time to validate.

Hardware, software and mechanical cosimulation for automotive applications

The design of automotive systems requires the joint design of hardware, software and micro-mechanical components. In traditional design approaches the different parts are designed by separate groups and the integration of the overall system is made at the final stage. This scheme may induce extra delays and costs because of interfacing problems. The paper presents a new automotive system design approach that offers many advantages including efficient design flow and shorter time to market. The key idea of our approach is to allow for early validation of the overall system through co-simulation. The design starts with a high level specification of each part. In our approach, software is described in C, hardware is described in VHDL and mechanical parts are described in MATLAB. A C-VHDL-MATLAB co-simulation is then used for functional validation of the initial specification. During the design process, the hardware and software parts may be refined using specific techniques and tools. The refinement steps are also validated through co-simulation. In this approach we use two kinds of co-simulation: untimed co-simulation is used for functional validation and timed co-simulation for real time validation. The paper describes the design approach and its successful application to an example from the automotive industry.

Objective Study of Sensor Relevance for Automatic Cough Detection

The development of a system for the automatic, objective, and reliable detection of cough events is a need underlined by the medical literature for years. The benefit of such a tool is clear as it would allow the assessment of pathology severity in chronic cough diseases. Even though some approaches have recently reported solutions achieving this task with a relative success, there is still no standardization about the method to adopt or the sensors to use. The goal of this paper is to study objectively the performance of several sensors for cough detection: ECG, thermistor, chest belt, accelerometer, contact, and audio microphones. Experiments are carried out on a database of 32 healthy subjects producing, in a confined room and in three situations, voluntary cough at various volumes as well as other event categories which can possibly lead to some detection errors: background noise, forced expiration, throat clearing, speech, and laugh. The relevance of each sensor is evaluated at three stages: mutual information conveyed by the features, ability to discriminate at the frame level cough from these latter other sources of ambiguity, and ability to detect cough events. In this latter experiment, with both an averaged sensitivity and specificity of about 94.5%, the proposed approach is shown to clearly outperform the commercial Karmelsonix system which achieved a specificity of 95.3% and a sensitivity of 64.9%.

Automatic VHDL-C Interface Generation for Distributed Cosimulation: Application to Large Design Examples

For functional validation of heterogeneous embedded systems, hardware/software (Hw/Sw) cosimulation methodology is mandatory. This paper deals with a distributed cosimulation environment for heterogeneous systems prototyping. The cosimulation environment allows handling all kinds of distributed architectures regardless the communication scheme used, cosimulation at different levels of abstraction and smooth transition to the cosynthesis process. The approach can handle any number of hardware modules, software modules, and debugging tools, which can be used simultaneously. This flexibility is obtained thanks to an automatic cosimulation interface generation tool, which creates links between Hw and Sw simulation environments. The resulting environment is very easy to use and our cosimulation model has been validated on very large industrial examples. The experiments show that VHDL-C cosimulation is faster than classical simulation approaches.

VHDL generation from SDL specifications

The aim of this paper is to present an approach that allows the generation of VHDL from system level specifications in SDL. Our approach overcomes the main known problem encountered by previous work, which is the communication between different processes. We allow SDL communication to be translated into VHDL for synthesis. This is made possible by the use of an intermediate form that supports a powerful communication model which enables the representation in a synthesis oriented manner of most communication schemes. This intermediate form allows the refinement of the system in order to obtain the desired solution. The main refinement step, called communication synthesis, is aimed at fixing the protocol and the interface used by the different processes to communicate. The refined specification is translated into VHDL for synthesis using existing CAD tools. We illustrate the feasibility of our approach through two SDL to VHDL translation examples.

Virtual Prototyping For Modular And Flexible Hardware-Software Systems

The goal of this work is to develop a methodology for fast prototyping of highly modular and flexible electronic systems including both, software and hardware. The main contribution of this work is the ability to handle a wide range of architectures. We assume that hardware/software partitioning is already made. This stage of the codesign process starts with a virtual prototype, an heterogeneous architecture composed of a set of distributed modules, represented in VHDL for hardware elements and in C for software elements, communicating through communication modules. This work concentrates on a modelling strategy that allow virtual prototype to be used for both cosynthesis (mapping hardware and software modules onto an architectural platform) and cosimulation (that is the joint simulation of hardware and software components) into an unified environment. The main contribution is the use of a multi-view library concept in order to hide specific hardware/software implementation details and communication schemes. In particular this approach addresses the problem of communication between the hardware and software modules.

MCI—multilanguage distributed co-simulation tool

Nowadays the design of complex systems requires the cooperation of several teams belonging to different cultures and using different languages. It is necessary to dispose of new design and verification methods to handle multilanguage approaches. This paper presents a multilanguage co-simulation tool that allows co-simulation of multilanguage specifications for complex systems. The main idea of our approach is to allow validation of the functional completeness of the system at a behavioral level. MCI starts with a configuration file that describes the interconnection between modules written in different languages. It generates automatically a software co-simulation bus and the interfaces required to connect the different simulators in a distributed way. The proposed tool is used to assist the design of an adaptive speed control system that was described in three different languages (VHDL, SDL and MatLab).

Trends In Embedded Systems Technology

While there has been much talk on the necessity of a major breakthrough in design methods and advanced CAD to support the multi-million gate chips that are already a reality, there has not been a clearly identified new direction which will produce a major productivity breakthrough. This paper attempts to identify one of these productivity breakthroughs, through: 1. an analysis of designer needs, 2. a study of embedded systems trends in the industry, 3. case studies in wireless communications and multi-media.