An Engineer's Guide to the LPC2100 Series
●7 commentsThis book is intended as a hands-on guide for anyone planning to use the Philips LPC2000 family of microcontrollers in a new design. It is laid out both as a reference book and as a tutorial. It is assumed that you have some experience in programming microcontrollers for embedded systems and are familiar with the C language. The bulk of technical information is spread over the first four chapters, which should be read in order if you are completely new to the LPC2000 and the ARM7 CPU.
Choosing An Ultralow-Power MCU
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
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
●8 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
●6 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.
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?
A Multithreaded Real-time Robot for Embedded Design Space Exploration
This thesis introduces an autonomous robot platform for real-time scheduling exper- imentation and benchmark suite to evaluate real-time optimizations and apply modern task scheduling methods. It makes two contributions. First, it presents a reference hardware and software design for a line-following, obstacle-avoiding and maze-solving robot. This robot is based on a small commercially-available product. The software is structured as a multithreaded real- time system for use in evaluating scheduling approaches for cost-sensitive and resource- constrained applications. Second, it provides a detailed design space exploration showing the costs (processor speed and memory) of di erent scheduling approaches (static vs. dynamic and non-preemptive vs. preemptive). It also measures and analyzes each task's timing information and explores the mini- mum microcontroller clock speed under di erent scheduling approaches.
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.
Creating a State-of-the Art, Cost Effective Energy Harvesting Bluetooth® Low Energy Switch
As IoT rapidly grows into new markets such as MHealth, Agriculture 4.0, and building automation, new questions are being raised about the energy required to support its growth. Within the industry, we see a broad spectrum of power requirements.
Transforming 64-Bit Windows to Deliver Software-Only Real-Time Performance
Next-generation industrial, vision, medical and other systems seek to combine highend graphics and rich user interfaces with hard real-time performance, prioritization and precision.Today’s industrial PCs running 64-bit Windows, complemented by a separate scheduler on multicore multiprocessors, can deliver that precise real-time performance on software-defined peripherals.
Demystifying digital signal processing (DSP) programming: The ease in realizing implementations with TI DSPs
Introduced by Texas Instruments over thirty years ago, the digital signal processor (DSP) has evolved in its implementation from a standalone processor to a multicore processing element and has continued to extend in its range of applications. The breadth of software development tools for the DSP has also expanded to accommodate diverse sets of programmers. From small, low power, yet “smart” devices with applications such as voice and image recognition, to multicore, high-performance compute platforms performing real-time data analytics, the opportunities to achieve the low-power processing efficiencies of DSPs are nearly endless. The TI DSP has benefited from a relatively unique tool suite evolution making it easy and effective for the general programmer and the signal processing expert alike to quickly develop their application code. This paper addresses how TI DSP users are able to achieve the high performance afforded by the TI DSP architecture, in an efficient, easy-to-use development environment.
Electrical Ground Rules Part 3
Best Practices for Grounding Your Electrical Equipment Examining the role of ground as a voltage stabilizer and transient limiter, along with tips on improving safety and signal integrity (Part 3 of 3)
Electrical Ground Rules Part 1
Best Practices for Grounding Your Electrical Equipment A look at circuit grounding and its importance to you, as well as the US AC power system and its use of earth ground (Part 1 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.
