Sistemas embarcados ganham cada vez mais espaço devido ao aumento da demanda por novas funções em equipamentos, às normas regulatórias e às novas necessidades dos consumidores e do mercado. Esse aumento nos requisitos aumenta o tamanho e a complexidade dos softwares embarcados cuja importância cresce significativamente. Sistemas operacionais de tempo real constituem uma ferramenta poderosa para gerenciar a complexidade, facilitar o reuso e aumentar a portabilidade do software e também reduzir o time-to-market. Este trabalho visa avaliar a aplicabilidade de sistemas operacionais de tempo real em sistemas embarcados de baixo custo que utilizam microprocessadores pequenos (8 e 16 bits), avaliando suas características e propondo as melhores alternativas para desenvolvimento de software embarcado. Para o atendimento desta proposta, foi realizado o levantamento de características sobre o desenvolvimento brasileiro de sistemas embarcados, uma análise das características de sistemas de pequeno porte, uma discussão da viabilidade do uso de RTOS e um estudo de caso comparando arquiteturas de software embarcado. Os resultados principais mostram que arquiteturas simplificadas como a Superloop apresentam vantagem sobre os sistemas operacionais devido ao baixo consumo de memória e processamento. Os sistemas operacionais, apesar de propiciarem desenvolvimentos de códigos modulares bem como facilitar o gerenciamento de tempo, são de difícil implementação em microcontroladores pequenos, devido ao seu elevado consumo de memória e processamento. O uso de sistemas operacionais é viável para sistemas de pequeno porte com no mínimo 4 Kbytes de memória RAM e processos com limite de tempo máximo para execução (deadlines) superiores a 1 ms, condições essas que evitam a sobrecarga do microcontrolador. Neste trabalho também é mostrado um retrato do desenvolvimento de embarcados no Brasil. / Embedded systems, more and more are gaining importance, due to the increase of features requested on equipments, the regulatory standards and the costumers and market requirements. This increment on requirements increases the software size and complexity, which importance significantly grows. Real-time operating systems represents a powerful tool to manage the complexity, help the software reuse and improve portability of the software and also reduce the time-to-market. This work aims to analyze the real-time operating systems, verifying their application on low cost embedded systems using small microcontrollers (8 and 16-bit), evaluating their characteristics and propose the best architectures for software development. To attend this proposal, it was performed a survey of Brazilian embedded system development, evaluates the low cost embedded system characteristics, discusses the viability of RTOS usage and performs a comparative study of embedded software architectures. Results show that simplified architectures like the Superloop presents vantages over the operating systems due to their low memory and processing consumption. The operating system, besides helping on time management and code modularity, is difficult to implement in small microcontrollers, due to the high memory and processing consumption. The operating systems are more applicable to small embedded systems with at minimum 4 Kbytes of RAM memory and process with maximum execution time (deadlines) over 1 ms, conditions that do not causes microcontroller overload. In this work is also presented an overview of Brazilian embedded system development.

Sistemas embarcados ganham cada vez mais espaço devido ao aumento da demanda por novas funções em equipamentos, às normas regulatórias e às novas necessidades dos consumidores e do mercado. Esse aumento nos requisitos aumenta o tamanho e a complexidade dos softwares embarcados cuja importância cresce significativamente. Sistemas operacionais de tempo real constituem uma ferramenta poderosa para gerenciar a complexidade, facilitar o reuso e aumentar a portabilidade do software e também reduzir o time-to-market. Este trabalho visa avaliar a aplicabilidade de sistemas operacionais de tempo real em sistemas embarcados de baixo custo que utilizam microprocessadores pequenos (8 e 16 bits), avaliando suas características e propondo as melhores alternativas para desenvolvimento de software embarcado. Para o atendimento desta proposta, foi realizado o levantamento de características sobre o desenvolvimento brasileiro de sistemas embarcados, uma análise das características de sistemas de pequeno porte, uma discussão da viabilidade do uso de RTOS e um estudo de caso comparando arquiteturas de software embarcado. Os resultados principais mostram que arquiteturas simplificadas como a Superloop apresentam vantagem sobre os sistemas operacionais devido ao baixo consumo de memória e processamento. Os sistemas operacionais, apesar de propiciarem desenvolvimentos de códigos modulares bem como facilitar o gerenciamento de tempo, são de difícil implementação em microcontroladores pequenos, devido ao seu elevado consumo de memória e processamento. O uso de sistemas operacionais é viável para sistemas de pequeno porte com no mínimo 4 Kbytes de memória RAM e processos com limite de tempo máximo para execução (deadlines) superiores a 1 ms, condições essas que evitam a sobrecarga do microcontrolador. Neste trabalho também é mostrado um retrato do desenvolvimento de embarcados no Brasil. / Embedded systems, more and more are gaining importance, due to the increase of features requested on equipments, the regulatory standards and the costumers and market requirements. This increment on requirements increases the software size and complexity, which importance significantly grows. Real-time operating systems represents a powerful tool to manage the complexity, help the software reuse and improve portability of the software and also reduce the time-to-market. This work aims to analyze the real-time operating systems, verifying their application on low cost embedded systems using small microcontrollers (8 and 16-bit), evaluating their characteristics and propose the best architectures for software development. To attend this proposal, it was performed a survey of Brazilian embedded system development, evaluates the low cost embedded system characteristics, discusses the viability of RTOS usage and performs a comparative study of embedded software architectures. Results show that simplified architectures like the Superloop presents vantages over the operating systems due to their low memory and processing consumption. The operating system, besides helping on time management and code modularity, is difficult to implement in small microcontrollers, due to the high memory and processing consumption. The operating systems are more applicable to small embedded systems with at minimum 4 Kbytes of RAM memory and process with maximum execution time (deadlines) over 1 ms, conditions that do not causes microcontroller overload. In this work is also presented an overview of Brazilian embedded system development.

Les systèmes multiprocesseurs sur puce (MPSoC) offrent des performances supérieures tout en conservant la flexibilité et la réutilisabilité grâce à la customisation du logiciel embarqué. Alors que la plupart de MPSoC sont aujourd'hui hétérogènes pour mieux répondre aux besoins des applications ciblées, les MPSoCs homogènes pourraient devenir dans un proche avenir une alternative viable apportant d'autres avantages tels que l'équilibrage de charge de l'exécution, la migration des tâches et l'ájustement de fréquence dynamique. Cette thèse s'appuie sur une plateforme MPSoC homogène, développée pour explorer techniques d'adaptation en ligne. Chaque processeur de ce système est compact et exécute un système d'exploitation préemptif qui surveille diverses métriques et est habilité à prendre des décisions de remapping grâce à des techniques de migration de code et du changement dynamique de la fréquence. Cette approche permet la mise en œuvre des capacités de raffinage d'application à l'exécution en fonction de différents critères. / Multiprocessor Systems-on-Chip (MPSoC) offer superior performance while maintaining flexibility and reusability thanks to software oriented personalization. While most MPSoCs are today heterogeneous for better meeting the targeted application requirements, homogeneous MPSoCs may become in a near future a viable alternative bringing other benefits such as run-time load balancing, task migration and dynamic frequency scaling. This thesis relies on a homogeneous NoC-based MPSoC platform developed for exploring scalable and adaptive on-line continuous mapping techniques. Each processor of this system is compact and runs a tiny preemptive operating system that monitors various metrics and is entitled to take remapping decisions through code migration techniques and dynamic frequency scaling. This approach that endows the architecture with decisional capabilities permits refining application implementation at run-time according to various criteria.

<p>Ett ramverk för kontraktbaserad schemaläggning av dynamisk resursfördelning i realtidsoperativsystem ska rapporteras till operativsystemet OSE. Ramverket, som utvecklats i ett EU-forskningsprojekt, kräver uppmätt process exekveringstid för att fatta riktiga schemaläggningsbeslut. Sådana mätningar görs för närvarande inte i ENEAs RTOS OSE och examensarbetets syfte har därför varit att undersöka möjligheterna att implementera en sådan funktion. Alternativ har hittats och utvärderats, slutligen har ett valts för implementation. Funktionalilteten har verifierats och slutlilgen har prestanda utvärderats hos den implementerade mätningsmetoden.</p>

£gC/OS-II is a portable, scalable and preemptive real time kernel. In this paper, we describe the work of porting £gC/OS-II to the Xilinx ML310 platform, which is equipped with a Virtex-II Pro FPGA. Moreover, we also present the accomplishment of an OS4RS (Operating System for Reconfigurable System) prototype by integrating £gC/OS-II with the partial reconfiguration capability of the Virtex-II Pro FPGA. For the porting of the £gC/OS-II, we mainly port the code related to context switch, interrupt, and timer. Moreover, for the OS4RS prototype, we partition the FPGA into four regions and allow different circuits (i.e. hardware tasks) to be dynamically reconfigured (i.e. downloaded) into the regions under the control of £gC/OS-II. Finally, we propose an algorithm to predict and pre-configure the hardware tasks so as to reduce the waiting time of task reconfiguration. According to the simulation results, the proposed algorithm can reduce the waiting time effectively.

<p>In this master thesis, we design and implemented a super mode for multiple streaming signal processing applications, and got the timing budget based on Senior DSP processor. This work presented great opportunity to study the real-time system and firmware design knowledge on embedded system.</p>

In this master thesis, we design and implemented a super mode for multiple streaming signal processing applications, and got the timing budget based on Senior DSP processor. This work presented great opportunity to study the real-time system and firmware design knowledge on embedded system.

Ett ramverk för kontraktbaserad schemaläggning av dynamisk resursfördelning i realtidsoperativsystem ska rapporteras till operativsystemet OSE. Ramverket, som utvecklats i ett EU-forskningsprojekt, kräver uppmätt process exekveringstid för att fatta riktiga schemaläggningsbeslut. Sådana mätningar görs för närvarande inte i ENEAs RTOS OSE och examensarbetets syfte har därför varit att undersöka möjligheterna att implementera en sådan funktion. Alternativ har hittats och utvärderats, slutligen har ett valts för implementation. Funktionalilteten har verifierats och slutlilgen har prestanda utvärderats hos den implementerade mätningsmetoden.

No description available.

System tracing is a helpful method for engineersand users to know exactly what happens in an operating system,especially in real-time operating systems (RTOS), because forreal-time system, it is normally more difficult to know theperformance of hardware and software than for desktopcomputers. Although this kind of tracing tools already exist forsome commercial RTOS, it is fairly hard to see those tools forsmall or open source RTOS. Moreover, because the structure andimplementation of different RTOS varies, it is rare to find aframework that can easily be ported to those platforms. In thisthesis, a solution is presented to this general tracing problem ondifferent platforms. By using the portable framework, it ispossible to implement tracing component into a real timeoperating system by some simple reconfigurations. This platformportability feature is accomplished by separating the specificplatform logic from the logic of the tracing part. Finally, adeployment of this framwork onto a small open source real-timeoperating system—AtomThreads, running on an AVRATmega1650 – is used as a demonstration of this framework.