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Clockless CPU
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 be ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Globally Asynchronous Locally Synchronous
Globally asynchronous locally synchronous (GALS), in electronics, is an architecture for Integrated circuit design, designing electronic circuits that 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 circuit, asynchronous communication, e.g. with FIFO (computing and electronics), 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 f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Signal Edge
In electronics, a signal edge is a transition of a digital signal from low to high or from high to low: * A rising edge (or positive edge) is the low-to-high transition. * A falling edge (or negative edge) is the high-to-low transition. In the case of a pulse, which consists of two edges: * The leading edge (or front edge) is the first edge of the pulse. * The trailing edge (or back edge) is the second edge of the pulse. See also *Flip-flop (electronics) In electronics, flip-flops and latches are electronic circuit, circuits that have two stable states that can store state information – a bistable multivibrator. The circuit can be made to change state by signals applied to one or more control ..., an edge-triggered circuit * Rise time, for a signal transition References Digital electronics {{Electronics-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Nullable Type
Nullable types are a feature of some programming languages which allow a value to be set to the special value NULL instead of the usual possible values of the data type. In statically typed languages, a nullable type is an option type, while in dynamically typed languages (where values have types, but variables do not), equivalent behavior is provided by having a single null value. NULL is frequently used to represent a missing value or invalid value, such as from a function that failed to return or a missing field in a database, as in NULL in SQL. In other words, NULL is undefined. Primitive types such as integers and Booleans cannot generally be null, but the corresponding nullable types (nullable integer and nullable Boolean, respectively) can also assume the NULL value. This can be represented in ternary logic as FALSE, NULL, TRUE as in three-valued logic. Example An integer variable may represent integers, but 0 (zero) is a special case because 0 in many programming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |
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Multi-valued Logic
Many-valued logic (also multi- or multiple-valued logic) is a propositional calculus in which there are more than two truth values. Traditionally, in Aristotle's logical calculus, there were only two possible values (i.e., "true" and "false") for any proposition. Classical two-valued logic may be extended to ''n''-valued logic for ''n'' greater than 2. Those most popular in the literature are three-valued (e.g., Łukasiewicz's and Kleene's, which accept the values "true", "false", and "unknown"), four-valued, nine-valued, the finite-valued (finitely-many valued) with more than three values, and the infinite-valued (infinitely-many-valued), such as fuzzy logic and probability logic. History It is ''wrong'' that the first known classical logician who did not fully accept the law of excluded middle was Aristotle (who, ironically, is also generally considered to be the first classical logician and the "father of wo-valuedlogic"). In fact, Aristotle did ''not'' contest ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] [Amazon] |