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Globally Asynchronous Locally Synchronous
Globally asynchronous locally synchronous (GALS), in electronics, is an architecture for designing electronic circuits which addresses the problem of safe and reliable data transfer between independent clock domains. GALS is a model of computation that emerged in the 1980s. It allows to design computer systems consisting of several synchronous islands (using synchronous programming for each such island) interacting with other islands using asynchronous communication, e.g. with FIFOs. Details A GALS circuit consists of a set of locally synchronous modules communicating with each other via asynchronous wrappers. Each synchronous subsystem ("clock domain") can run on its own independent clock (frequency). Advantages include much lower electromagnetic interference (EMI). The CMOS circuit (logic gates) requires relatively large supply current when changing state from 0 to 1. These changes are aggregated for synchronous circuit as most changes are initialised by an active clock edge. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electronics
The field of electronics is a branch of physics and electrical engineering that deals with the emission, behaviour and effects of electrons using electronic devices. Electronics uses active devices to control electron flow by amplification and rectification, which distinguishes it from classical electrical engineering, which only uses passive effects such as resistance, capacitance and inductance to control electric current flow. Electronics has hugely influenced the development of modern society. The central driving force behind the entire electronics industry is the semiconductor industry sector, which has annual sales of over $481 billion as of 2018. The largest industry sector is e-commerce, which generated over $29 trillion in 2017. History and development Electronics has hugely influenced the development of modern society. The identification of the electron in 1897, along with the subsequent invention of the vacuum tube which could amplify and rectify small ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asynchronous Circuit
Asynchronous circuit (clockless or self-timed circuit) is a sequential digital logic circuit that does not use a global clock circuit or signal generator to synchronize its components. Instead, the components are driven by a handshaking circuit which indicates a completion of a set of instructions. Handshaking works by simple data transfer protocols. Many synchronous circuits were developed in early 1950s as part of bigger asynchronous systems (e.g. ORDVAC). Asynchronous circuits and theory surrounding is a part of several steps in integrated circuit design, a field of digital electronics engineering. Asynchronous circuits are contrasted with synchronous circuits, in which changes to the signal values in the circuit are triggered by repetitive pulses called a clock signal. Most digital devices today use synchronous circuits. However asynchronous circuits have a potential to be much faster, have a lower level of power consumption, electromagnetic interference, and better modular ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SIGNAL (programming Language)
SIGNAL is a programming language based on synchronized data-flow (flows + synchronization): a process is a set of equations on elementary flows describing both data and control. The SIGNAL formal model provides the capability to describe systems with several clocks (polychronous systems) as relational specifications. Relations are useful as partial specifications and as specifications of non-deterministic devices (for instance a non-deterministic bus) or external processes (for instance an unsafe car driver). Using SIGNAL allows one to specify an application, to design an architecture, to refine detailed components down to RTOS or hardware description. The SIGNAL model supports a design methodology which goes from specification to implementation, from abstraction to concretization, from synchrony to asynchrony. SIGNAL has been mainly developed iINRIAhttp://www.inria.fr/en/en/teams/espresso Espresso team] since the 1980s, at the same time as similar programming languages, Es ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Clock Domain Crossing
In digital electronic design a clock domain crossing (CDC), or simply clock crossing, is the traversal of a signal in a synchronous digital circuit from one clock domain into another. If a signal does not assert long enough and is not registered, it may appear asynchronous on the incoming clock boundary. A synchronous system is composed of a single electronic oscillator that generates a clock signal, and its clock domain—the memory elements directly clocked by that signal from that oscillator, and the combinational logic attached to the outputs of those memory elements. Because of speed-of-light delays, timing skew, etc., the size of a clock domain in such a synchronous system is inversely proportional to the frequency of the clock. In early computers, typically all the digital logic ran in a single clock domain. Because of transmission line loss and distortion it is difficult to carry digital signals above 66 MHz on standard PCB traces (the clock signal is the highest fre ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asynchronous System
The primary focus of this article is asynchronous control in digital electronic systems. In a synchronous system, operations (instructions, calculations, logic, etc.) are coordinated by one, or more, centralized clock signals. An asynchronous system, in contrast, has no global clock. Asynchronous systems do not depend on strict arrival times of signals or messages for reliable operation. Coordination is achieved using event-driven architecture triggered by network packet arrival, changes (transitions) of signals, handshake protocols, and other methods. Modularity Asynchronous systems – much like object-oriented software – are typically constructed out of modular 'hardware objects', each with well-defined communication interfaces. These modules may operate at variable speeds, whether due to data-dependent processing, dynamic voltage scaling, or process variation. The modules can then be combined to form a correct working system, without reference to a global clock sign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Concurrency (computer Science)
In computer science, concurrency is the ability of different parts or units of a program, algorithm, or problem to be executed out-of-order or in partial order, without affecting the outcome. This allows for parallel execution of the concurrent units, which can significantly improve overall speed of the execution in multi-processor and multi-core systems. In more technical terms, concurrency refers to the decomposability of a program, algorithm, or problem into order-independent or partially-ordered components or units of computation. According to Rob Pike, concurrency is the composition of independently executing computations, and concurrency is not parallelism: concurrency is about dealing with lots of things at once but parallelism is about doing lots of things at once. Concurrency is about structure, parallelism is about execution, concurrency provides a way to structure a solution to solve a problem that may (but not necessarily) be parallelizable. A number of mathema ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asynchronous Programming
Asynchrony, in computer programming, refers to the occurrence of events independent of the main program flow and ways to deal with such events. These may be "outside" events such as the arrival of signals, or actions instigated by a program that take place concurrently with program execution, without the program blocking to wait for results. Asynchronous input/output is an example of the latter case of asynchrony, and lets programs issue commands to storage or network devices that service these requests while the processor continues executing the program. Doing so provides a degree of parallelism. A common way for dealing with asynchrony in a programming interface is to provide subroutines that return a future or promise that represents the ongoing operation, and a synchronizing operation that blocks until the future or promise is completed. Some programming languages, such as Cilk, have special syntax for expressing an asynchronous procedure call. Examples of asynchrony inclu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Synchronous Programming
Synchronization is the coordination of events to operate a system in unison. For example, the conductor of an orchestra keeps the orchestra synchronized or ''in time''. Systems that operate with all parts in synchrony are said to be synchronous or ''in sync''—and those that are not are ''asynchronous''. Today, time synchronization can occur between systems around the world through satellite navigation signals and other time and frequency transfer techniques. Navigation and railways Time-keeping and synchronization of clocks is a critical problem in long-distance ocean navigation. Before radio navigation and satellite-based navigation, navigators required accurate time in conjunction with astronomical observations to determine how far east or west their vessel traveled. The invention of an accurate marine chronometer revolutionized marine navigation. By the end of the 19th century, important ports provided time signals in the form of a signal gun, flag, or dropping time ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Asynchronous Array Of Simple Processors
Asynchrony is the state of not being in synchronization. Asynchrony or asynchronous may refer to: Electronics and computing * Asynchrony (computer programming), the occurrence of events independent of the main program flow, and ways to deal with such events ** Async/await * Asynchronous system, a system having no global clock, instead operating under distributed control ** Asynchronous circuit, a sequential digital logic circuit not governed by a clock circuit or signal ** Asynchronous communication, transmission of data without the use of an external clock signal * Asynchronous cellular automaton, a mathematical model of discrete cells which update their state independently * Asynchronous operation, a sequence of operations executed out of time coincidence with any event Other uses * Asynchrony (game theory), when players in games update their strategies at different time intervals * Asynchronous learning, an educational method in which the teacher and student are separated in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network On A Chip
A network on a chip or network-on-chip (NoC or )This article uses the convention that "NoC" is pronounced . Therefore, it uses the convention "a" for the indefinite article corresponding to NoC ("a NoC"). Other sources may pronounce it as and therefore use "an NoC". is a network-based communications subsystem on an integrated circuit ("microchip"), most typically between modules in a system on a chip ( SoC). The modules on the IC are typically semiconductor IP cores schematizing various functions of the computer system, and are designed to be modular in the sense of network science. The network on chip is a router-based packet switching network between SoC modules. NoC technology applies the theory and methods of computer networking to on-chip communication and brings notable improvements over conventional bus and crossbar communication architectures. Networks-on-chip come in many network topologies, many of which are still experimental as of 2018. In 2000s researcher ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
System On A Chip
A system on a chip or system-on-chip (SoC ; pl. ''SoCs'' ) is an integrated circuit that integrates most or all components of a computer or other electronic system. These components almost always include a central processing unit (CPU), memory interfaces, on-chip input/output devices, input/output interfaces, and secondary storage interfaces, often alongside other components such as radio modems and a graphics processing unit (GPU) – all on a single substrate or microchip. It may contain digital, analog, mixed-signal, and often radio frequency signal processing functions (otherwise it is considered only an application processor). Higher-performance SoCs are often paired with dedicated and physically separate memory and secondary storage (such as LPDDR and eUFS or eMMC, respectively) chips, that may be layered on top of the SoC in what's known as a package on package (PoP) configuration, or be placed close to the SoC. Additionally, SoCs may use separate wireless modems. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Decoupling Capacitor
A decoupling capacitor is a capacitor used to decouple one part of an electrical network (circuit) from another. Noise caused by other circuit elements is shunted through the capacitor, reducing its effect on the rest of the circuit. For higher frequencies an alternative name is bypass capacitor as it is used to bypass the power supply or other high impedance component of a circuit. Discussion Active devices of an electronic system (transistors, ICs, vacuum tubes, for example) are connected to their power supplies through conductors with finite resistance and inductance. If the current drawn by an active device changes, voltage drops from power supply to device will also change due to these impedances. If several active devices share a common path to the power supply, changes in the current drawn by one element may produce voltage changes large enough to affect the operation of others – voltage spikes or ground bounce, for example – so the change of state of one device is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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