EmbeddedRelated.com
Filtered by topic: IoT [clear filter]
Choosing An Ultralow-Power MCU

Choosing An Ultralow-Power MCU

Mike Mitchell
Still RelevantIntermediate

This application report describes how to compare ultralow-power MCUs. It discusses the key differences between popular low-power MCUs and how to interpret features and specifications and apply them to application requirements


Driving I2C-Bus Signals Over Twisted Pair Cables with PCA9605

Driving I2C-Bus Signals Over Twisted Pair Cables with PCA9605

NXP Semiconductors
Still RelevantIntermediate

The availability of powerful I2C buffers that drive their I/Os on both sides to a nominal ground or ‘zero offset’ logic level allows the removal of noise introduced into one section of a larger bus system. That ‘regeneration’ of clean I2C signals enables building long I2C buses by combining together relatively short bus sections, each say less than 20 meters, using such buffers or multiplexers that contain them. Conventional twisted pair communication cabling with its convenient connectors, and a ‘modular’ I2C system approach, make large system assembly easy. Each drop point or node can be individually selected for bidirectional data communication with the Master just by using normal I2C software addressing. As an example, a system is described for control of LED lighting displays and it is suggested that the power for the LEDs, and the I2C control system, might be economically provided using ‘extra low voltage’ distribution at 48 V using either the control signal cable or similar low cost wiring in a manner similar to that used in ‘Power over the Ethernet’ systems. The simplicity and flexibility of this approach makes it attractive to consider as an alternative to other control systems such as RS-485 or CAN bus.


Arduino  Programming  Notebook

Arduino Programming Notebook

Brian W. Evans
Still RelevantBeginner

This notebook serves as a convenient, easy to use programming reference for the command structure and basic syntax of the Arduino microcontroller. To keep it simple, certain exclusions were made that make this a beginner’s reference best used as a secondary source alongside other websites, books, workshops, or classes. This decision has lead to a slight emphasis on using the Arduino for standalone purposes and, for example, excludes the more complex uses of arrays or advanced forms of serial communication.


Introduction to Embedded Systems - A Cyber-Physical Systems Approach

Introduction to Embedded Systems - A Cyber-Physical Systems Approach

E. A. Lee, S. A. Seshia
Still RelevantIntermediate

This book strives to identify and introduce the durable intellectual ideas of embedded systems as a technology and as a subject of study. The emphasis is on modeling, design, and analysis of cyber-physical systems, which integrate computing, networking, and physical processes. This book is intended for students at the advanced undergraduate level or the introductory graduate level, and for practicing engineers and computer scientists who wish to understand the engineering principles of embedded systems.


Embedded Systems – Theory and Design Methodology

Embedded Systems – Theory and Design Methodology

Kiyofumi Tanaka (Editor)
Still RelevantAdvanced

This book addresses a wide spectrum of research topics on embedded systems, including basic researches, theoretical studies, and practical work.


High Performance Systems, Applications and Projects

High Performance Systems, Applications and Projects

Kiyofumi Tanaka (Editor)
Still RelevantAdvanced

This book addresses a wide spectrum of research topics of embedded systems, including parallel computing, communication architecture, application-specific systems, and embedded systems projects.


Consistent Overhead Byte Stuffing

Consistent Overhead Byte Stuffing

Stuart Cheshire, Mary Baker
TimelessIntermediate

Byte stuffing is a process that transforms a sequence of data bytes that may contain ‘illegal’ or ‘reserved’ values into a potentially longer sequence that contains no occurrences of those values. The extra length is referred to in this paper as the overhead of the algorithm. To date, byte stuffing algorithms, such as those used by SLIP [RFC1055], PPP [RFC1662] and AX.25 [ARRL84], have been designed to incur low average overhead but have made little effort to minimize worst case overhead. Some increasingly popular network devices, however, care more about the worst case. For example, the transmission time for ISM-band packet radio transmitters is strictly limited by FCC regulation. To adhere to this regulation, the practice is to set the maximum packet size artificially low so that no packet, even after worst case overhead, can exceed the transmission time limit. This paper presents a new byte stuffing algorithm, called Consistent Overhead Byte Stuffing (COBS), that tightly bounds the worst case overhead. It guarantees in the worst case to add no more than one byte in 254 to any packet. Furthermore, the algorithm is computationally cheap, and its average overhead is very competitive with that of existing algorithms.


Design and Implementation of the lwIP Stack

Design and Implementation of the lwIP Stack

Adam Dunkels
Still RelevantAdvanced

LwIP is an implementation of the TCP/IP protocol stack. The focus of the lwIP stack is to reduce memory usage and code size, making lwIP suitable for use in small clients with very limited resources such as embedded systems. In order to reduce processing and memory demands, lwIP uses a tailor made API that does not require any data copying. This report describes the design and implementation of lwIP. The algorithms and data struc- tures used both in the protocol implementations and in the sub systems such as the memory and bu®er management systems are described. Also included in this report is a reference manual for the lwIP API and some code examples of using lwIP.


An Embedded Object Approach to Embedded System Development

An Embedded Object Approach to Embedded System Development

Tero Valliu
Still RelevantIntermediate

Building an embedded system from an idea to a product is a slow and expensive process requiring a lot of expertise. Depending on the developer’s expertise, the required quantity and price level of the final product, and the time and money available for development, the developer can build a device from different granularity of components, ranging from ready-made platforms, kits, and modules to individual components. Generally, solutions requiring less expertise, time and money produce products with higher production costs. The main contribution of this thesis is the EOC (Embedded Object Concept) and Atomi II Framework. EOC utilizes common object-oriented methods used in software by applying them to small electronic modules, which create complete functional entities. The conceptual idea of the embedded objects is implemented with the Atomi II framework, which contains several techniques for making the EOC a commercially feasible implementation. The EOC and the Atomi II Framework decreases the difficulty level of making embedded systems by enabling a use of ready-made modules to build systems. It enables automatic conversion of a device made from such modules into an integrated PCB, lowering production costs compared to other modular approaches. Furthermore, it also enables an automatic production tester generation due to its modularity. These properties lower the number of skills required for building an embedded system and quicken the path from an idea to a commercially applicable device. A developer can also build custom modules of his own if he possesses the required expertise. The test cases demonstrate the Atomi II Framework techniques in real world applications, and demonstrate the capabilities of Atomi objects. According to our test cases and estimations, an Atomi based device becomes approximately 10% more expensive than a device built from individual components, but saves up to 50% time, making it feasible to manufacture up to 10-50k quantities with this approach.


Topics in Secure Embedded System Design

Topics in Secure Embedded System Design

Nachiketh Potlapall
Still RelevantAdvanced

Pervasive networks have led to widespread use of embedded systems, like cell phones, PDAs, RFIDs etc., in increasingly diverse applications. Many of these embedded system appli- cations handle sensitive data (e.g., credit card information on a mobile phone/PDA) or perform critical functions (e.g., medical devices or automotive electronics), and the use of security protocols is imperative to maintain con dentiality, integrity and authentication of these applications. Typically embedded systems have low computing power and nite energy supply based on a battery, and these factors are at odds with the computationally intensive nature of the cryptographic algorithms underlying many security protocols. In addition, secure embedded systems are vulnerable to attacks, like physical tampering, malware and side-channel attacks. Thus, design of secure embedded systems is guided by the following factors: small form factor, good performance, low energy consumption (and, thus,longer battery life), and robustness to attacks. This thesis presents our work on tackling three issues in the design of secure embedded systems: energy consumption, performance and robustness to side-channel attacks. First, we present our work on optimizing the energy consumption of the widely employed secure sockets layer (SSL) protocol running on an embedded system. We discuss results of energy analysis of various cryptographic algorithms, and the manner in which this information can be used to adapt the operation of SSL protocol to save energy. Next, we present results of our experiments on optimizing the performance of Internet protocol security (IPSec) protocol on an embedded processor. Depending on the mode of operation, the IPSec computation is dominated by cryptographic or non-cryptographic processing. We demonstrate how both these components of the IPSec protocol can be optimized by leveraging the extensible and con gurable features of an embedded processor. Next, we introduce a satisfability-based framework for enabling side-channel attacks on cryptographic software running on an embedded processor. This framework enables us to identify variables in the software implementations which result in the disclosure of the secret key used. Thus, security of software implementations can be improved by better protection of these identified variables. Finally, we conclude by introducing a novel memory integrity checking protocol that has much lower communication complexity than existing Merkle tree-based protocols while incurring a modest price in computation on the processor. This scheme is based on Toeplitz matrices, and can be very efficiently realized on embedded systems with hardware extensions for bit matrix operations.