Interrupts, Low Power Modes and Timer A
This document contains a lot of what you need to know to get the most out of the MSP430. The MSP430 line is renowned for it's low power usage, and to really utilize it well you have to architect your software to be an interrupt driven device that utilizes the low power modes.
PID Without a PhD
●7 commentsPID (proportional, integral, derivative) control is not as complicated as it sounds. Follow these simple implementation steps for quick results.
Reed-Solomon Error Correction
[Best paper on Reed-Solomon error correction I have ever read -- and it's from the BBC!] Reed-Solomon error correction has several applications in broadcasting,in particular forming part of the specification for the ETSI digital terrestrial television standard, known as DVB-T. Hardware implementations of coders and decoders for Reed-Solomon error correction are complicated and require some knowledge of the theory of Galois fields on which they are based. This note describes the underlying mathematics and the algorithms used for coding and decoding,with particular emphasis on their realisation in logic circuits. Worked examples are provided to illustrate the processes involved.
Memory allocation in C
●5 commentsThis article is about dynamic memory allocation in C in the context of embedded programming. It describes the process of dynamically allocating memory with visual aids. The article concludes with a practical data communications switch example which includes a sample code in C.
Advanced Linux Programming
●5 commentsThis book is intended for learning advanced linux programming.
Red Hat Linux - The Complete Reference
This book identifies seven major Linux topics: basic setup, environments and applications, the Internet, servers, administration, and network administration. These topics are integrated into the different ways Red Hat presents its distribution: as a desktop workstation, network workstation, server, and development platform
Essential Linux Device Drivers
●5 commentsThis book is about writing Linux device drivers. It covers the design and development of major device classes supported by the kernel, including those I missed during my Linux-on-Watch days. The discussion of each driver family starts by looking at the corresponding technology, moves on to develop a practical example, and ends by looking at relevant kernel source files. Before foraying into the world of device drivers, however, this book introduces you to the kernel and discusses the important features of 2.6 Linux, emphasizing those portions that are of special interest to device driver writers.
CPU Memory - What Every Programmer Should Know About Memory
●6 commentsAs CPU cores become both faster and more numerous, the limiting factor for most programs is now, and will be for some time, memory access. Hardware designers have come up with ever more sophisticated memory handling and acceleration techniques–such as CPU caches–but these cannot work optimally without some help from the programmer. Unfortunately, neither the structure nor the cost of using the memory subsystem of a computer or the caches on CPUs is well understood by most programmers. This paper explains the structure of memory subsystems in use on modern commodity hardware, illustrating why CPU caches were developed, how they work, and what programs should do to achieve optimal performance by utilizing them.
Driving I2C-Bus Signals Over Twisted Pair Cables with PCA9605
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.
C++ Tutorial
●5 commentsThese tutorials explain the C++ language from its basics up to the newest features of ANSI-C++, including basic concepts such as arrays or classes and advanced concepts such as polymorphism or templates. The tutorial is oriented in a practical way, with working example programs in all sections to start practicing each lesson right away
Arduino Microcontroller Guide
●3 commentsThe Arduino microcontroller is an easy to use yet powerful single board computer that has gained considerable traction in the hobby and professional market. The Arduino is open-source, which means hardware is reasonably priced and development software is free. This guide is for students in ME 2011, or students anywhere who are confronting the Arduino for the first time. For advanced Arduino users, prowl the web; there are lots of resources.
Interrupts, Low Power Modes and Timer A
This document contains a lot of what you need to know to get the most out of the MSP430. The MSP430 line is renowned for it's low power usage, and to really utilize it well you have to architect your software to be an interrupt driven device that utilizes the low power modes.
Driving I2C-Bus Signals Over Twisted Pair Cables with PCA9605
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
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.
Embedded Linux Primer
●4 commentsThis book brings together indispensable knowledge for building efficient, high-value, Linux-based embedded products: information that has never been assembled in one place before. Drawing on years of experience as an embedded Linux consultant and field application engineer, Christopher Hallinan offers solutions for the specific technical issues you're most likely to face, demonstrates how to build an effective embedded Linux environment, and shows how to use it as productively as possible.
Electrical Ground Rules Part 2
Best Practices for Grounding Your Electrical Equipment Examining our use of ground as protection, and how ground fault circuit interrupter devices operate to protect us from severe shock (Part 2 of 3)
New Life for Embedded Systems in the Internet of Things
The Internet of Things (IoT) is no longer a fanciful vision. It is very much with us, in everything from factory automation to on-demand entertainment. Yet by most accounts, the full potential of interconnected systems and intelligent devices for changing the way we work and live has barely been tapped. Up until now, IoT software solutions have largely had to be built from scratch with a high degree of customization to specific requirements, which has driven up the cost and complexity of development and deterred many prospective entrants to the market. What have been missing are developer tools that alleviate the costs associated with building the foundational infrastructure—the “plumbing” of their solutions—so they can focus on optimizing the core functionality and bring solutions to market more quickly with less cost. Wind River® is addressing these challenges with new solutions that have the potential to expand the market for IoT by reducing the cost and complexity of development. This document outlines the challenges that IoT poses for developers, and how Wind River solutions can help overcome them.
A Guide to Approximations
Most embedded processors don’t know how to compute trig and other complex functions. Programming in C we’re content to call a library routine that does all of the work for us. Unhappily this optimistic approach often fails in real time systems where size, speed and accuracy are all important issues. The compiler’s runtime package is a one-size-fits-all proposition. It gives a reasonable trade-off of speed and precision. But every embedded system is different, with different requirements. In some cases it makes sense to write our own approximation routines. Why?
Embedded Touchscreen Handbook
I want to add a touchscreen to my embedded product. Where do I start? That question is common nowadays. Most manufacturing companies are seeing the value – maybe the necessity – of touch screen technology. Many of them don’t have a long-term or close association with the technology, yet they expect their embedded engineers to handle the project successfully and on a tight schedule. These engineers often have questions... - How much am I going to have to learn to get the job done? - I’ve heard that LCD suppliers were not like other suppliers. But, how so? - What don’t I know that could shift the project from “exciting” to “doomed.” You have choices: Probably the three major questions that crop up when you need to add an LCD touch screen to your product are these: - Should I use a full-blown, embedded operating system, like Windows CE, CE Linux or QNX? - How much work does it take to develop an in-house LCD system from scratch? - Do I have other options? The answer to the first two questions is a resounding “maybe,” (depending on what you need to accomplish). The answer to the third question is, probably “yes.” In most cases, there is another option. Who should read this? If you are an embedded engineer who is thinking of adding a touch screen to your product, and if: - You need to know what is involved in adding color touch controls to your product. -You need to understand the risks (both known and hidden) involved in LCD technology. - Your main area of expertise is not LCD technology. - You don’t want to re-focus your time to acquire color LCD technology expertise. If you find that any of the statements above voice your concerns, you may find this paper worth reading.
Time in Wireless Embedded System
●1 commentWireless embedded networks have matured beyond academic research as industry now considers the advantages of using wireless sensors. With this growth, reliability and real-time demands increase, thus timing becomes more and more relevant. In this dissertation, we focus on the development of highly stable, low-power clock systems for wireless embedded systems. Wireless embedded networks, due to their wire-free nature, present one of the most extreme power budget design challenges in the field of electronics. Improvements in timing can reduce the energy required to operate an embedded network. However, the more accurate a time source is, the more power it consumes. To comprehensively address the time and power problems in wireless embedded systems, this dissertation studies the exploitation of dual-crystal clock architectures to combat effects of temperature induced frequency error and high power consumption of high-frequency clocks. Combining these architectures with the inherent communication capabilities of wireless embedded systems, this dissertation proposes two new technologies; (1) a new time synchronization service that automatically calibrates a local clock to changes in temperature; (2) a high-low frequency timer that allows a duty-cycled embedded system to achieve ultra low-power sleep, while keeping fine granularity time resolution offered only by high power, high frequency clocks.
