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A complex programmable logic device (CPLD) is a programmable logic device with complexity between that of PALs and FPGAs, and architectural features of both. The main building block of the CPLD is a macrocell, which contains logic implementing disjunctive normal form expressions and more specialized logic operations.
Some of the CPLD features are in common with PALs:
Other features are in common with FPGAs:
The most noticeable difference between a large CPLD and a small FPGA is the presence of on-chip non-volatile memory in the CPLD, which allows CPLDs to be used for "boot loader" functions, before handing over control to other devices not having their own permanent program storage. A good example is where a CPLD is used to load configuration data for an FPGA from non-volatile memory. [1]
CPLDs were an evolutionary step from even smaller devices that preceded them: PLAs (first shipped by Signetics) and PALs. These in turn were preceded by standard logic products, which offered no programmability and were used to build logic functions by physically wiring several standard logic chips (or hundreds of them) together (usually with wiring on a printed circuit board or boards, but sometimes, especially for prototyping, using wire wrap wiring).
The main distinction between FPGA and CPLD device architectures is that CPLDs are internally based on a collection of PLDs accompanied by a programmable interconnection structure, while FPGAs use logic blocks.
A field-programmable gate array (FPGA) is a type of configurable integrated circuit that can be programmed or reprogrammed after manufacturing. FPGAs are part of a broader set of logic devices referred to as programmable logic devices (PLDs). They consist of an array of programmable logic blocks and interconnects that can be configured to perform various digital functions. FPGAs are commonly used in applications where flexibility, speed, and parallel processing capabilities are required, such as in telecommunications, automotive, aerospace, and industrial sectors.
A logic gate is a device that performs a Boolean function, a logical operation performed on one or more binary inputs that produces a single binary output. Depending on the context, the term may refer to an ideal logic gate, one that has, for instance, zero rise time and unlimited fan-out, or it may refer to a non-ideal physical 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, the function of a PLD is undefined 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.
An application-specific integrated circuit 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 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.
Altera Corporation was a manufacturer of programmable logic devices (PLDs) headquartered in San Jose, California. It was founded in 1983 and acquired by Intel in 2015.
A programmable logic array (PLA) is a kind of programmable logic device used to implement combinational logic circuits. The PLA has a set of programmable AND gate planes, which link to a set of programmable OR gate planes, which can then be conditionally complemented to produce an output. It has 2N AND gates for N input variables, and for M outputs from the PLA, there should be M OR gates, each with programmable inputs from all of the AND gates. This layout allows for many logic functions to be synthesized in the sum of products canonical forms.
Programmable Array Logic (PAL) is a family of programmable logic device semiconductors used to implement logic functions in digital circuits that was introduced by Monolithic Memories, Inc. (MMI) in March 1978. MMI obtained a registered trademark on the term PAL for use in "Programmable Semiconductor Logic Circuits". The trademark is currently held by Lattice Semiconductor.
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 according to custom order by adding metal interconnect layers in the factory. It was popular during the upheaval in the semiconductor industry in the 1980s, and its usage declined by the end of the 1990s.
A programmer, device programmer, chip programmer, device burner, or PROM writer is a piece of electronic equipment that arranges written software or firmware to configure programmable non-volatile integrated circuits, called programmable devices. The target devices include PROM, EPROM, EEPROM, Flash memory, eMMC, MRAM, FeRAM, NVRAM, PLDs, PLAs, PALs, GALs, CPLDs, FPGAs, and microcontrollers.
The Generic Array Logic device was an innovation of the PAL and was invented by Lattice Semiconductor. The GAL was an improvement on the PAL because one device type was able to take the place of many PAL device types or could even have functionality not covered by the original range of PAL devices. Its primary benefit, however, was that it was erasable and re-programmable, making prototyping and design changes easier for engineers.
Altera Hardware Description Language (AHDL) is a proprietary hardware description language (HDL) developed by Altera Corporation. AHDL is used for digital logic design entry for Altera's complex programmable logic devices (CPLDs) and field-programmable gate arrays (FPGAs). It is supported by Altera's MAX-PLUS and Quartus series of design software. AHDL has an Ada-like syntax and its feature set is comparable to the synthesizable portions of the Verilog and VHDL hardware description languages. In contrast to HDLs such as Verilog and VHDL, AHDL is a design-entry language only; all of its language constructs are synthesizable. By default, Altera software expects AHDL source files to have a .tdf extension.
An electronic device or embedded system is said to be field-programmable or in-place programmable if its firmware can be modified "in the field", without disassembling the device or returning it to its manufacturer.
A simple programmable logic device (SPLD) is a programmable logic device with complexity below that of a complex programmable logic device (CPLD).
Computing with Memory refers to computing platforms where function response is stored in memory array, either one or two-dimensional, in the form of lookup tables (LUTs) and functions are evaluated by retrieving the values from the LUTs. These computing platforms can follow either a purely spatial computing model, as in field-programmable gate array (FPGA), or a temporal computing model, where a function is evaluated across multiple clock cycles. The latter approach aims at reducing the overhead of programmable interconnect in FPGA by folding interconnect resources inside a computing element. It uses dense two-dimensional memory arrays to store large multiple-input multiple-output LUTs. Computing with Memory differs from Computing in Memory or processor-in-memory (PIM) concepts, widely investigated in the context of integrating a processor and memory on the same chip to reduce memory latency and increase bandwidth. These architectures seek to reduce the distance the data travels between the processor and the memory. The Berkeley IRAM project is one notable contribution in the area of PIM architectures.
Xilinx ISE is a discontinued software tool from Xilinx for synthesis and analysis of HDL designs, which primarily targets development of embedded firmware for Xilinx FPGA and CPLD integrated circuit (IC) product families. It was succeeded by Xilinx Vivado. Use of the last released edition from October 2013 continues for in-system programming of legacy hardware designs containing older FPGAs and CPLDs otherwise orphaned by the replacement design tool, Vivado Design Suite.
The following outline is provided as an overview of and topical guide to electronics:
The GAL22V10 is a series of programmable-logic devices from Lattice Semiconductor, implemented as CMOS-based generic array logic ICs, and available in dual inline packages or plastic leaded chip carriers. It is an example of a standard production GAL device that is often used in educational settings as a basic programmable-logic device. In combinatorial mode, it is conceptually a group of programmable AND-OR-invert (AOI) (AND-NOR) gates or AND-OR gates.
Circuit underutilization also chip underutilization, programmable circuit underutilization, gate underutilization, logic block underutilization refers to a physical incomplete utility of semiconductor grade silicon on a standardized mass-produced circuit programmable chip, such as a gate array type ASIC, an FPGA, or a CPLD.
In computing, a logic block or configurable logic block (CLB) is a fundamental building block of field-programmable gate array (FPGA) technology. Logic blocks can be configured by the engineer to provide reconfigurable logic gates.
iCE is the brand name used for a family of low-power field-programmable gate arrays (FPGAs) produced by Lattice Semiconductor. Parts in the family are marketed with the "world's smallest FPGA" tagline, and are intended for use in portable and battery-powered devices, where they would be used to offload tasks from the device's main processor or system on chip. By doing so, the main processor and its peripherals can enter a low-power state or be powered off entirely, potentially increasing battery life.
