System Power Management Interface
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System Power Management Interface
The System Power Management Interface (SPMI) is a high-speed, low- latency, bi-directional, two-wire serial bus suitable for real-time control of voltage and frequency scaled multi-core application processors and its power management of auxiliary components. SPMI obsoletes a number of legacy, custom point-to-point interfaces and provides a low pin count, high-speed control bus for up to 4 master and 16 slave devices. SPMI is specified by the MIPI Alliance MIPI Alliance is a global business alliance that develops technical specifications for the mobile ecosystem, particularly smart phones but including mobile-influenced industries. MIPI was founded in 2003 by ARM, Intel, Nokia, Samsung, STMicroele ... (Mobile Industry Process Interface Alliance). References Serial buses Computer standards MIPI Alliance standards {{Comp-hardware-stub ...
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Latency (engineering)
Latency, from a general point of view, is a time delay between the cause and the effect of some physical change in the system being observed. Lag, as it is known in gaming circles, refers to the latency between the input to a simulation and the visual or auditory response, often occurring because of network delay in online games. Latency is physically a consequence of the limited velocity at which any physical interaction can propagate. The magnitude of this velocity is always less than or equal to the speed of light. Therefore, every physical system with any physical separation (distance) between cause and effect will experience some sort of latency, regardless of the nature of the stimulation at which it has been exposed to. The precise definition of latency depends on the system being observed or the nature of the simulation. In communications, the lower limit of latency is determined by the medium being used to transfer information. In reliable two-way communication syst ...
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Duplex (telecommunications)
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 ...
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Serial Communication
In telecommunication and data transmission, serial communication is the process of sending data one bit at a time, sequentially, over a communication channel or computer bus. This is in contrast to parallel communication, where several bits are sent as a whole, on a link with several parallel channels. Serial communication is used for all long-haul communication and most computer networks, where the cost of cable and synchronization difficulties make parallel communication impractical. Serial computer buses are becoming more common even at shorter distances, as improved signal integrity and transmission speeds in newer serial technologies have begun to outweigh the parallel bus's advantage of simplicity (no need for serializer and deserializer, or SerDes) and to outstrip its disadvantages (clock skew, interconnect density). The migration from PCI to PCI Express is an example. Cables Many serial communication systems were originally designed to transfer data over relatively ...
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Bus (computing)
In computer architecture, a bus (shortened form of the Latin '' omnibus'', and historically also called data highway or databus) is a communication system that transfers data between components inside a computer, or between computers. This expression covers all related hardware components (wire, optical fiber, etc.) and software, including communication protocols. Early computer buses were parallel electrical wires with multiple hardware connections, but the term is now used for any physical arrangement that provides the same logical function as a parallel electrical busbar. Modern computer buses can use both parallel and bit serial connections, and can be wired in either a multidrop (electrical parallel) or daisy chain topology, or connected by switched hubs, as in the case of Universal Serial Bus (USB). Background and nomenclature Computer systems generally consist of three main parts: * The central processing unit (CPU) that processes data, * The memory that holds the p ...
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Real-time Computing
Real-time computing (RTC) is the computer science term for hardware and software systems subject to a "real-time constraint", for example from event to system response. Real-time programs must guarantee response within specified time constraints, often referred to as "deadlines". Ben-Ari, Mordechai; "Principles of Concurrent and Distributed Programming", ch. 16, Prentice Hall, 1990, , page 164 Real-time responses are often understood to be in the order of milliseconds, and sometimes microseconds. A system not specified as operating in real time cannot usually ''guarantee'' a response within any timeframe, although ''typical'' or ''expected'' response times may be given. Real-time processing ''fails'' if not completed within a specified deadline relative to an event; deadlines must always be met, regardless of system load. A real-time system has been described as one which "controls an environment by receiving data, processing them, and returning the results sufficiently quic ...
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Voltage Scaling
Dynamic voltage scaling is a power management technique in computer architecture, where the voltage used in a component is increased or decreased, depending upon circumstances. Dynamic voltage scaling to increase voltage is known as overvolting; dynamic voltage scaling to decrease voltage is known as undervolting. Undervolting is done in order to conserve power, particularly in laptops and other mobile devices, where energy comes from a battery and thus is limited, or in rare cases, to increase reliability. Overvolting is done in order to support higher frequencies for performance. The term "overvolting" is also used to refer to increasing static operating voltage of computer components to allow operation at higher speed (overclocking). Background MOSFET-based digital circuits operate using voltages at circuit nodes to represent logical state. The voltage at these nodes switches between a high voltage and a low voltage during normal operation—when the inputs to a logic gat ...
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Frequency Scaling
In computer architecture, frequency scaling (also known as frequency ramping) is the technique of increasing a processor's frequency so as to enhance the performance of the system containing the processor in question. Frequency ramping was the dominant force in commodity processor performance increases from the mid-1980s until roughly the end of 2004. The effect of processor frequency on computer speed can be seen by looking at the equation for computer program runtime: : \mathrm = \frac \times \frac \times \frac , where instructions per program is the total instructions being executed in a given program, cycles per instruction is a program-dependent, architecture-dependent average value, and time per cycle is by definition the inverse of processor frequency. An increase in frequency thus decreases runtime. However, power consumption in a chip is given by the equation : P = C \times V^2 \times F, where ''P'' is power consumption, ''C'' is the capacitance being switched per cl ...
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Point-to-point (telecommunications)
In telecommunications, a point-to-point connection refers to a communications connection between two communication endpoints or nodes. An example is a telephone call, in which one telephone is connected with one other, and what is said by one caller can only be heard by the other. This is contrasted with a ''point-to-multipoint'' or ''broadcast'' connection, in which many nodes can receive information transmitted by one node. Other examples of point-to-point communications links are leased lines and microwave radio relay. The term is also used in computer networking and computer architecture to refer to a wire or other connection that links only two computers or circuits, as opposed to other network topologies such as buses or crossbar switches which can connect many communications devices. ''Point-to-point'' is sometimes abbreviated as ''P2P''. This usage of ''P2P'' is distinct from ''P2P'' meaning ''peer-to-peer'' in the context of file sharing networks or other data-sh ...
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Master (technology)
Master or masters may refer to: Ranks or titles * Ascended master, a term used in the Theosophical religious tradition to refer to spiritually enlightened beings who in past incarnations were ordinary humans *Grandmaster (chess), National Master, International Master, FIDE Master, Candidate Master, all ranks of chess player * Grandmaster (martial arts) or Master, an honorary title * Grand master (order), a title denoting the head of an order or knighthood * Grand Master (Freemasonry), the head of a Grand Lodge and the highest rank of a Masonic organization * Maestro, an orchestral conductor, or the master within some other musical discipline *Master, a title of Jesus in the New Testament *Master or shipmaster, the sea captain of a merchant vessel *Master (college), head of a college *Master (form of address), an English honorific for boys and young men * Master (judiciary), a judicial official in the courts of common law jurisdictions * Master mariner, a licensed mariner who is q ...
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Slave (technology)
Master/slave is a model of asymmetric communication or control where one device or process (the "master") controls one or more other devices or processes (the "slaves") and serves as their communication hub. In some systems, a master is selected from a group of eligible devices, with the other devices acting in the role of slaves. The ''master/slave'' terminology was first used in 1904. Since the early 21st century, the terms have become a subject of controversy from their association with slavery and some organizations have opted to replace them with alternative terms. Examples * In electronics, master/slave relationships are used to describe some of the following scenarios: ** In parallel ATA hard drive arrangements, the terms master and slave are used to describe drives on the same cable, but neither drive has control or priority over the other. ** A master clock that provides time signals used to synchronize one or more slave clocks as part of a clock network. ** In AXI, ...
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MIPI Alliance
MIPI Alliance is a global business alliance that develops technical specifications for the mobile ecosystem, particularly smart phones but including mobile-influenced industries. MIPI was founded in 2003 by ARM, Intel, Nokia, Samsung, STMicroelectronics and Texas Instruments Texas Instruments Incorporated (TI) is an American technology company headquartered in Dallas, Texas, that designs and manufactures semiconductors and various integrated circuits, which it sells to electronics designers and manufacturers globall .... Non-member organizations have limited access to MIPI standards, with some exceptions. The exceptions generally take the form of a ''public'' version of the standard. An example of one of these exceptions is the ''I3C (bus), I3C Basic standard'' which requires no license from MIPI to implement. The organization comprises about 330 member companies worldwide, 15 active working groups and has delivered more than 45 specifications within the mobile ecosystem ...
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Serial Buses
Serial may refer to: Arts, entertainment, and media The presentation of works in sequential segments * Serial (literature), serialised literature in print * Serial (publishing), periodical publications and newspapers * Serial (radio and television), series of radio and television programs that rely on a continuing plot * Serial film, a series of short subjects, with a continuing story, originally shown in theaters, in conjunction with feature films, particularly in the 1930s and 1940s * Indian serial, a type of Indian television program Other uses in arts, entertainment, and media * ''Serial'' (1980 film), based on McFadden's novel, starring Martin Mull and Tuesday Weld * ''Serial'' (podcast), a podcast spinoff of the radio series ''This American Life'' * ''The Serial: A Year in the Life of Marin County'', a 1977 novel by Cyra McFadden Computing and technology * SerDes, a Serializer/Deserializer (pronounced sir-deez) * Serial ATA * Serial attached SCSI * Serial bus, e.g., **IĀ ...
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