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Digital Timing Diagram
A digital timing diagram represents a set of signals in the time domain. A timing diagram can contain many rows, usually one of them being the clock. It is a tool commonly used in digital electronics, hardware debugging, and digital communications. Besides providing an overall description of the timing relationships, the digital timing diagram can help find and diagnose digital logic hazards. Diagram convention Most timing diagrams use the following conventions: * Higher value is a logic one * Lower value is a logic zero * A slot showing a high and low is an either-or (such as on a data line) * A Z indicates high impedance * A greyed out slot is a don't-care or indeterminate. Example: SPI bus timing The timing diagram example on the right describes the Serial Peripheral Interface (SPI) Bus. Most SPI master nodes can set the clock polarity (CPOL) and clock phase (CPHA) with respect to the data. This timing diagram shows the clock for both values of CPOL and the values for the tw ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hazard (logic)
In digital logic, a hazard is an undesirable effect caused by either a deficiency in the system or external influences in both synchronous and asynchronous circuits. Logic hazards are manifestations of a problem in which changes in the input variables do not change the output correctly due to some form of delay caused by logic elements ( NOT, AND, OR gates, etc.) This results in the logic not performing its function properly. The three different most common kinds of hazards are usually referred to as static, dynamic and function hazards. Hazards are a temporary problem, as the logic circuit will eventually settle to the desired function. Therefore, in synchronous designs, it is standard practice to register the output of a circuit before it is being used in a different clock domain or routed out of the system, so that hazards do not cause any problems. If that is not the case, however, it is imperative that hazards be eliminated as they can have an effect on other connected s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
High Impedance
In electronics, high impedance means that a point in a circuit (a node) allows a relatively small amount of current through, per unit of applied voltage at that point. High impedance circuits are low current and potentially high voltage, whereas low impedance circuits are the opposite (low voltage and potentially high current). Numerical definitions of "high impedance" vary by application. High impedance inputs are preferred on measuring instruments such as voltmeters or oscilloscopes. In audio systems, a high-impedance input may be required for use with devices such as crystal microphones or other devices with high internal impedance. Analog electronics In analog circuits a high impedance node is one that does not have any low impedance paths to any other nodes ''in the frequency range being considered''. Since the terms low and high depend on context to some extent, it is possible in principle for some high impedance nodes to be described as low impedance in one context, and hi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Don't-care (logic)
In digital logic, a don't-care term (abbreviated DC, historically also known as ''redundancies'', ''irrelevancies'', ''optional entries'', ''invalid combinations'', ''vacuous combinations'', ''forbidden combinations'', ''unused states'' or ''logical remainders'') for a function is an input-sequence (a series of bits) for which the function output does not matter. An input that is known never to occur is a can't-happen term. Both these types of conditions are treated the same way in logic design and may be referred to collectively as ''don't-care conditions'' for brevity. The designer of a logic circuit to implement the function need not care about such inputs, but can choose the circuit's output arbitrarily, usually such that the simplest circuit results ( minimization). Don't-care terms are important to consider in minimizing logic circuit design, including graphical methods like Karnaugh–Veitch maps and algebraic methods such as the Quine–McCluskey algorithm. In 1958, S ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
SPI Timing Diagram2
SPI may refer to: Organizations * Indian Protection Service (''Serviço de Proteção ao Índio''), Brazil * Shotmed Paper Industries, an Egyptian paper manufacturers * Simulations Publications, Inc., a former US board game publisher * Sony Pictures Imageworks * Stream Processors, Inc, a semiconductor company * Sisters of Perpetual Indulgence, an LGBT group * Society for Philosophical Inquiry * Society of the Plastics Industry, a U.S. trade association * Software in the Public Interest * Software Patent Institute, US * St. Pascual Institution, Philippines school * St. Paul's Institution, a school in Malaysia * Sustainable Preservation Initiative, of cultural heritage * Sveriges Pensionärers Intresseparti, or Swedish Senior Citizen Interest Party * Social Progress Imperative, a US-based nonprofit created in 2012 Computing * SCSI Parallel Interface * Serial Peripheral Interface * Security Parameter Index in IPSec tunneling * Service provider interface, an API * Softwa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serial Peripheral Interface Bus
The Serial Peripheral Interface (SPI) is a synchronous serial communication interface specification used for short-distance communication, primarily in embedded systems. The interface was developed by Motorola in the mid-1980s and has become a ''de facto'' standard. Typical applications include Secure Digital cards and liquid crystal displays. SPI devices communicate in full duplex mode using a master-slave architecture usually with a single master (though some Atmel and Silabs devices support changing roles on the fly depending on an external (SS) pin). The master (controller) device originates the frame for reading and writing. Multiple slave-devices may be supported through selection with individual chip select (CS), sometimes called slave select (SS) lines. Sometimes SPI is called a ''four-wire'' serial bus, contrasting with three-, two-, and one-wire serial buses. The SPI may be accurately described as a synchronous serial interface, but it is different from the Sy ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Slave Select
Chip select (CS) or slave select (SS) is the name of a control line in digital electronics used to select one (or a set) of integrated circuits (commonly called "chips") out of several connected to the same computer bus, usually utilizing the three-state logic. One bus that uses the chip/slave select is the Serial Peripheral Interface Bus (SPI bus). When an engineer needs to connect several devices to the same set of input wires (e.g., a computer bus), but retain the ability to send and receive data or commands to each device independently of the others on the bus, they can use a chip select. The chip select is a command pin on many integrated circuits which connects the I/O pins on the device to the internal circuitry of that device. When the chip select pin is held in the inactive state, the chip or device is "deaf", and pays no heed to changes in the state of its other input pins; it holds its outputs in the high impedance state, so other chips can drive those signals. Wh ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Full Duplex
A duplex communication system is a point-to-point system composed of two or more connected parties or devices that can communicate with one another in both directions. Duplex systems are employed in many communications networks, either to allow for simultaneous communication in both directions between two connected parties or to provide a reverse path for the monitoring and remote adjustment of equipment in the field. There are two types of duplex communication systems: full-duplex (FDX) and half-duplex (HDX). In a full-duplex system, both parties can communicate with each other simultaneously. An example of a full-duplex device is plain old telephone service; the parties at both ends of a call can speak and be heard by the other party simultaneously. The earphone reproduces the speech of the remote party as the microphone transmits the speech of the local party. There is a two-way communication channel between them, or more strictly speaking, there are two communication channel ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Byte
The byte is a unit of digital information that most commonly consists of eight bits. Historically, the byte was the number of bits used to encode a single character of text in a computer and for this reason it is the smallest addressable unit of memory in many computer architectures. To disambiguate arbitrarily sized bytes from the common 8-bit definition, network protocol documents such as The Internet Protocol () refer to an 8-bit byte as an octet. Those bits in an octet are usually counted with numbering from 0 to 7 or 7 to 0 depending on the bit endianness. The first bit is number 0, making the eighth bit number 7. The size of the byte has historically been hardware-dependent and no definitive standards existed that mandated the size. Sizes from 1 to 48 bits have been used. The six-bit character code was an often-used implementation in early encoding systems, and computers using six-bit and nine-bit bytes were common in the 1960s. These systems often had memory wo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PlantUML
PlantUML is an open-source tool allowing users to create diagrams from a plain text language. Besides various UML diagrams, PlantUML has support for various other software development related formats (such as Archimate, Block diagram, BPMN, C4, Computer network diagram, ERD, Gantt chart, Mind map, and WBD), as well as visualisation of JSON and YAML files. The language of PlantUML is an example of a domain-specific language. Besides its own DSL, PlantUML also understands AsciiMath, Creole, DOT, and LaTeX. It uses Graphviz software to lay out its diagrams and Tikz for LaTeX support. Images can be output as PNG, SVG, LaTeX and even ASCII art. PlantUML has also been used to allow blind people to design and read UML diagrams. Applications that use PlantUML There are various extensions or add-ons that incorporate PlantUML. * Atom has a community maintained PlantUML syntax highlighter and viewer. * Confluence wiki has a PlantUML plug-in for Confluence Server, which ren ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diagrams
A diagram is a symbolic representation of information using visualization techniques. Diagrams have been used since prehistoric times on walls of caves, but became more prevalent during the Enlightenment. Sometimes, the technique uses a three-dimensional visualization which is then projected onto a two-dimensional surface. The word '' graph'' is sometimes used as a synonym for diagram. Overview The term "diagram" in its commonly used sense can have a general or specific meaning: * ''visual information device'' : Like the term "illustration", "diagram" is used as a collective term standing for the whole class of technical genres, including graphs, technical drawings and tables. * ''specific kind of visual display'' : This is the genre that shows qualitative data with shapes that are connected by lines, arrows, or other visual links. In science the term is used in both ways. For example, Anderson (1997) stated more generally: "diagrams are pictorial, yet abstract, represent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Digital Systems
Digital electronics is a field of electronics involving the study of digital signals and the engineering of devices that use or produce them. This is in contrast to analog electronics and analog signals. Digital electronic circuits are usually made from large assemblies of logic gates, often packaged in integrated circuits. Complex devices may have simple electronic representations of Boolean logic functions. History The binary number system was refined by Gottfried Wilhelm Leibniz (published in 1705) and he also established that by using the binary system, the principles of arithmetic and logic could be joined. Digital logic as we know it was the brain-child of George Boole in the mid 19th century. In an 1886 letter, Charles Sanders Peirce described how logical operations could be carried out by electrical switching circuits.Peirce, C. S., "Letter, Peirce to A. Marquand", dated 1886, '' Writings of Charles S. Peirce'', v. 5, 1993, pp. 541–3. GooglPreview See Burks, Arthur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premises in a topic-neutral way. When used as a countable noun, the term "a logic" refers to a logical formal system that articulates a proof system. Formal logic contrasts with informal logic, which is associated with informal fallacies, critical thinking, and argumentation theory. While there is no general agreement on how formal and informal logic are to be distinguished, one prominent approach associates their difference with whether the studied arguments are expressed in formal or informal languages. Logic plays a central role in multiple fields, such as philosophy, mathematics, computer science, and linguistics. Logic studies arguments, which consist of a set of premises together with a conclusion. Premises and conclusions are usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
