The PIC Microcontroller Family
The PIC microcontroller family is manufactured by Microchip Technology Inc. Currently
they are one of the most popular microcontrollers, used in many commercial and industrial
applications. Over 120 million devices are sold each year.
The PIC microcontroller architecture is based on a modified Harvard RISC (Reduced Instruction
Set Computer) instruction set with dual-bus architecture, providing fast and fl exible design
with an easy migration path from only 6 pins to 80 pins, and from 384 bytes to 128 kbytes of
PIC microcontrollers are available with many different specifi cations depending on:
• Memory Type
– OTP (One-time-programmable) …… READ MORERead More
Introduction A number of guidelines are available for C code optimization, there is no substitute for having a thorough knowledge of the compiler and machine for which you are programming. Often, speeding up a program can also cause the code's size to increase. This increment in code size can also have an adverse effect onRead More
Vulnerability Assesment and Penetration Testing There are hundreds of free security tools available on internet.Here I will try to give a comprehensive list of set of security tools which can serve the complete puropse of Vulnerability Assesment and Penetration Testing.Vulnerability assesment involves finding the known/unknown vulnerabilities in a computer systems or a network.PenetrationRead More
The PCI-SIG, an industry organization dedicated to developing and enhancing PCI/PCI Express (PCIe) technology, has successfully developed the PCI, PCI-X and PCIe Gen 1 and Gen 2 interconnect protocols and promoted the deployment of these technologies since PCI's inception in 1992.
In early 2008, the PCI-SIG announced the establishment of a workgroup chartered with the development of the next generation of PCIe " the PCI Express Base Specification 3.0, or PCIe Gen 3.
The Gen 3 specification is yet another step forward in enhancing the usefulness of the PCIe protocol by doubling the effective bandwidth and adding protocol enhancements to increase end-system performance.
Leading up to this development, IBM and Intel in 2006 launched an initiative called Geneseo, proposing extensions to the PCIe protocol for high-performance computing and visual processing.
Recommendations from this initiative were provided to the PCI-SIG as potential PCIe protocol enhancements. In addition to the adoption of Geneseo, several other engineering change notices (ECNs) were released by the PCI-SIG, providing enhancements for the efficiency and usefulness of the PCIe protocol.
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FPGA-Field Programmable Gate Array and CPLD-Complex Programmable Logic Device– both are programmable logic devices made by the same companies with different characteristics.
- "A Complex Programmable Logic Device (CPLD) is a Programmable Logic Device with complexity between that of PALs (Programmable Array Logic) and FPGAs, and architectural features of both. The building block of a CPLD is the macro cell, which contains logic implementing disjunctive normal form expressions and more specialized logic operations".
- Go to Wikipedia to get more information about it.
- Granularity is the biggest difference between CPLD and FPGA.
- FPGA are "fine-grain" devices. That means that they contain hundreds of (up to 100000) of tiny blocks (called as LUT or CLBs etc) of logic with flip-flops, combinational logic and memories.FPGAs offer much higher complexity, up to 150,000 flip-flops and large number of gates available.
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How Programmable Logic Works
In recent years, the line between hardware and software has blurred. Hardware now engineers create the bulk of their new digital circuitry in programming languages such as VHDL and Verilog. This article will help you make sense of programmable logic.
A quiet revolution is taking place. Over the past few years, the density of the average programmable logic device has begun to skyrocket. The maximum number of gates in an FPGA is currently around 500,000 and doubling every 18 months. Meanwhile, the price of these chips is dropping. What all of this means is that the price of an individual NAND or NOR is rapidly approaching zero! And the designers of embedded systems are taking note. Some system designers are buying processor cores and incorporating them into system-on-a-chip designs; others are eliminating the processor and software altogether, choosing an alternative hardware-only design.
As this trend continues, it becomes more difficult to separate hardware from software. After all, both hardware and software designers are now describing logic in high-level terms, albeit in different languages, and downloading the compiled result to a piece of silicon. Surely no one would claim that language choice alone marks a real distinction between the two fields. Turing's notion of machine-level equivalence and the existence of language-to-language translators have long ago taught us all that that kind of reasoning is foolish. There are even now products that allow designers to create their hardware designs in traditional programming languages like C. So language differences alone are not enough of a distinction.
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Introduction In the days of modern means of obtaining information ,Anyone with amost no knowledge can write code. Even teenagers can sling gates and PAL equations around. What is it that separates us from these amateurs? Do years of college necessarily make us professionals, or is there some other factor that clearly delineates engineers from hackers? WithRead More
A microcontroller is a computer with most of the necessary support chips
onboard. All computers have several things in common, namely:
- A central processing unit (CPU) that ‘executes’ programs.
- Some random-access memory (RAM) where it can store data that is variable.
- Some read only memory (ROM) where programs to be executed can be stored.
- Input and output (I/O) devices that enable communication to be established
with the outside world i.e. connection to devices such as keyboard, mouse,
monitors and other peripherals.
There are a number of other common characteristics that define microcontrollers.
If a computer matches a majority of these characteristics, then it can be
classified as a ‘microcontroller’. Microcontrollers may be:
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Atoms and electrons
Everybody knows about atoms and electrons don't they? Well we could skip this part but of course we won't because you will likely learn something new.
Electron theory states all matter is comprised of molecules, which in turn are comprised of atoms, which are again comprised of protons, neutrons and electrons. A molecule is the smallest part of matter which can exist by itself and contains one or more atoms.
If you turn on a light switch for example you will see the light bulb (globe) glow and emit light into the room. So what caused this to happen? How does energy travel through copper wires to light the bulb? How does energy travel through space? What makes a motor turn, a radio play?
To understand these processes requires an understanding of the basic principles. For the light to glow requires energy to find a path through the light switch, through the copper wire and this movement is called electron flow. It is also called current flow in electronics. This is the first important principle to understand.
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Development of Electromotive Force
• Faraday's Law
• Application of Faraday's Law
• A Single Coil DC Motor
• Motor Constants
In the early 1830’s, Michael Faraday and Joseph Henry independently discovered the relationship between changing magnetic fields and induced EMF in circuits. If B is the flux density of a constant magnetic field and a conductor is moved through this field at a velocity V, an EMF E is generated in the conductor such that:
If the conductor is part of a complete electrical circuit with a resistance R, then the EMF will produce a current in the conductor such that:
I = E / R = B x V / R
The development of an EMF in a conductor moving in a magnetic field is the principle on which many types of tachometers are based. By using the commutation
techniques described in the next section, a rotary device can be constructed which has, as its input, a rotary mechanical motion and, as its output, a voltage proportional to that input rotational velocity. Another specific application of Faraday’s Law is used in electric motors. That is, if a conductor of length L carrying a current I is placed in a magnetic field B, a magnetic force F is created such that:
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