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Macrocell Array
Macrocell arrays in PLDs Programmable logic devices, such as programmable array logic and complex programmable logic devices, typically have a macrocell on every output pin. Macrocell arrays in ASICs A macrocell array is an approach to the design and manufacture of ASICs. Essentially, it is a small step up from the otherwise similar gate array, but rather than being a prefabricated array of simple logic gates, the macrocell array is a prefabricated array of higher-level logic functions such as flip-flops, ALU functions, registers, and the like. These logic functions are simply placed at regular predefined positions and manufactured on a wafer, usually called master slice. Creation of a circuit with a specified function is accomplished by adding metal interconnects to the chips on the master slice late in the manufacturing process, allowing the function of the chip to be customised as desired. Macrocell array master slices are usually prefabricated and stockpiled in lar ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Macrocell
A macrocell or macrosite is a cell in a mobile phone network that provides radio coverage served by a high power cell site (tower, antenna or mast). Generally, macrocells provide coverage larger than microcell. The antennas for macrocells are mounted on ground-based masts, rooftops and other existing structures, at a height that provides a clear view over the surrounding buildings and terrain. Macrocell base stations have power outputs of typically tens of watts. Macrocell performance can be increased by increasing the efficiency of the transceiver. Scale The term macrocell is used to describe the widest range of cell sizes. Macrocells are found in rural areas or along highways. Over a smaller cell area, a microcell is used in a densely populated urban area. Picocells are used for areas smaller than microcells, such as a large office, a mall, or train station. Currently the smallest area of coverage that can be implemented with a femtocell is a home or small office. See also * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
MacroCell
A macrocell or macrosite is a cell in a mobile phone network that provides radio coverage served by a high power cell site (tower, antenna or mast). Generally, macrocells provide coverage larger than microcell. The antennas for macrocells are mounted on ground-based masts, rooftops and other existing structures, at a height that provides a clear view over the surrounding buildings and terrain. Macrocell base stations have power outputs of typically tens of watts. Macrocell performance can be increased by increasing the efficiency of the transceiver. Scale The term macrocell is used to describe the widest range of cell sizes. Macrocells are found in rural areas or along highways. Over a smaller cell area, a microcell is used in a densely populated urban area. Picocells are used for areas smaller than microcells, such as a large office, a mall, or train station. Currently the smallest area of coverage that can be implemented with a femtocell is a home or small office. See also * ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programmable Logic Device
A programmable logic device (PLD) is an electronic component used to build reconfigurable digital circuits. Unlike digital logic constructed using discrete logic gates with fixed functions, a PLD has an undefined function at the time of manufacture. Before the PLD can be used in a circuit it must be programmed to implement the desired function. Compared to fixed logic devices, programmable logic devices simplify the design of complex logic and may offer superior performance. Unlike for microprocessors, programming a PLD changes the connections made between the gates in the device. PLDs can broadly be categorised into, in increasing order of complexity, Simple Programmable Logic Devices (SPLDs), comprising programmable array logic, programmable logic array and generic array logic; Complex Programmable Logic Devices (CPLDs) and Field-Programmable Gate Arrays (FPGAs). History In 1969, Motorola offered the XC157, a mask-programmed gate array with 12 gates and 30 uncommitted ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Programmable Array Logic
Programmable Array Logic (PAL) is a family of programmable logic device semiconductors used to implement logic functions in digital circuits introduced by Monolithic Memories, Inc. (MMI) in March 1978. Introductory advertisement on PAL (Programmable Array Logic). MMI obtained a registered trademark on the term PAL for use in "Programmable Semiconductor Logic Circuits". The trademark is currently held by Lattice Semiconductor.Monolithic Memories, Inc (MMI) filed for a work mark on the term "PAL" for use in "Programmable Semiconductor Logic Circuits" on April 13, 1978. A registered trademark was granted on April 29, 1980, registration number 1134025. MMI's first use of the term PAL in commerce was on February 21, 1978. The trademark is currently held by Lattice Semiconductor Corporation of Hillsboro, Oregon. Source: United States Patent and Trademark Office online database. PAL devices consisted of a small PROM (programmable read-only memory) core and additional output logic used ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Application-specific Integrated Circuit
An application-specific integrated circuit (ASIC ) is an integrated circuit (IC) chip customized for a particular use, rather than intended for general-purpose use, such as a chip designed to run in a digital voice recorder or a high-efficiency video codec. Application-specific standard product (ASSP) chips are intermediate between ASICs and industry standard integrated circuits like the 7400 series or the 4000 series. ASIC chips are typically fabricated using metal-oxide-semiconductor (MOS) technology, as MOS integrated circuit chips. As feature sizes have shrunk and design tools improved over the years, the maximum complexity (and hence functionality) possible in an ASIC has grown from 5,000 logic gates to over 100 million. Modern ASICs often include entire microprocessors, memory blocks including ROM, RAM, EEPROM, flash memory and other large building blocks. Such an ASIC is often termed a SoC (system-on-chip). Designers of digital ASICs often use a hardware descrip ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gate Array
A gate array is an approach to the design and manufacture of application-specific integrated circuits (ASICs) using a prefabricated chip with components that are later interconnected into logic devices (e.g. NAND gates, flip-flops, etc.) according to a custom order by adding metal interconnect layers in the factory. It was popular during upheaval in semiconductor industry in 80s and its usage declined by end of 90s. Similar technologies have also been employed to design and manufacture analog, analog-digital, and structured arrays, but, in general, these are not called gate arrays. Gate arrays have also been known as ''uncommitted logic arrays'' (''ULAs''), which also offered linear circuit functions, and ''semi-custom chips''. History Development Gate arrays had several concurrent development paths. Ferranti in the UK pioneered commercializing bipolar ULA technology, offering circuits of "100 to 10,000 gates and above" by 1983. The company's early lead in semi-custom chips, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flip-flop (electronics)
In electronics, a flip-flop or latch is a circuit that has two stable states and can be used to store state information – a bistable multivibrator. The circuit can be made to change state by signals applied to one or more control inputs and will have one or two outputs. It is the basic storage element in sequential logic. Flip-flops and latches are fundamental building blocks of digital electronics systems used in computers, communications, and many other types of systems. Flip-flops and latches are used as data storage elements. A flip-flop is a device which stores a single ''bit'' (binary digit) of data; one of its two states represents a "one" and the other represents a "zero". Such data storage can be used for storage of ''state'', and such a circuit is described as sequential logic in electronics. When used in a finite-state machine, the output and next state depend not only on its current input, but also on its current state (and hence, previous inputs). It can also b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arithmetic Logic Unit
In computing, an arithmetic logic unit (ALU) is a Combinational logic, combinational digital circuit that performs arithmetic and bitwise operations on integer binary numbers. This is in contrast to a floating-point unit (FPU), which operates on floating point numbers. It is a fundamental building block of many types of computing circuits, including the central processing unit (CPU) of computers, FPUs, and graphics processing units (GPUs). The inputs to an ALU are the data to be operated on, called operands, and a code indicating the operation to be performed; the ALU's output is the result of the performed operation. In many designs, the ALU also has status inputs or outputs, or both, which convey information about a previous operation or the current operation, respectively, between the ALU and external status registers. Signals An ALU has a variety of input and output net (electronics), nets, which are the electrical conductors used to convey Digital signal (electronics), digi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hardware Register
In digital electronics, especially computing, hardware registers are circuits typically composed of flip flops, often with many characteristics similar to memory, such as: * The ability to read or write multiple bits at a time, and * Using an address to select a particular register in a manner similar to a memory address. Their distinguishing characteristic, however, is that they also have special hardware-related functions beyond those of ordinary memory. So, depending on the point of view, hardware registers are like memory with additional hardware-related functions; or, memory circuits are like hardware registers that just store data. Hardware registers are used in the interface between software and peripherals. Software writes them to send information to the device, and reads them to get information from the device. Some hardware devices also include registers that are not visible to software, for their internal use. Depending on their complexity, modern hardware devices c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wafer (electronics)
In electronics, a wafer (also called a slice or substrate) is a thin slice of semiconductor, such as a crystalline silicon Crystalline silicon or (c-Si) Is the crystalline forms of silicon, either polycrystalline silicon (poly-Si, consisting of small crystals), or monocrystalline silicon (mono-Si, a continuous crystal). Crystalline silicon is the dominant semiconduc ... (c-Si), used for the fabrication of integrated circuits and, in photovoltaics, to manufacture solar cells. The wafer serves as the substrate (materials science), substrate for microelectronic devices built in and upon the wafer. It undergoes many microfabrication processes, such as doping (semiconductor), doping, ion implantation, Etching (microfabrication), etching, thin-film deposition of various materials, and Photolithography, photolithographic patterning. Finally, the individual microcircuits are separated by wafer dicing and Integrated circuit packaging, packaged as an integrated circuit. History I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Full Custom
Full-custom design is a methodology for designing integrated circuits by specifying the layout of each individual transistor and the interconnections between them. Alternatives to full-custom design include various forms of semi-custom design, such as the repetition of small transistor subcircuits;{{cite book , title = The VLSI handbook , author = Rajneesh kaswan , publisher = CRC Press , year = 1999 , isbn = 0-8493-8593-8 , url = https://books.google.com/books?id=0r5LihlMogkC&q=%22full+custom+design%22&pg=PT853 one such methodology is the use of standard cell libraries (standard cell libraries are themselves designed using full-custom design techniques). Full-custom design potentially maximizes the performance of the chip, and minimizes its area, but is extremely labor-intensive to implement. Full-custom design is limited to ICs that are to be fabricated in extremely high volumes, notably certain microprocessors and a small number of ASICs. As of 2008 the main facto ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
