Semiconductor_intellectual_property_core

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Semiconductor intellectual property core

In electronic design a semiconductor intellectual property core, IP block, IP core, or logic core is a reusable unit of logic, cell, or chip layout design and is also the intellectual property of one party. IP cores may be licensed to another party or can also be owned and used by a single party alone. The term is derived from the licensing of the patent and source code copyright intellectual property rights that subsist in the design. IP cores can be used as building blocks within ASIC chip designs or FPGA logic designs.

In digital-logic applications, IP cores are typically offered as generic gate netlists. The netlist is a boolean-algebra representation (gates, standard cells) of the IP's logical-function, analogous to an assembly-code listing for a high-level program application. The netlist protects the vendor against reverse-engineering, while maintaining portability to multiple foundry targets. Some vendors also offer synthesizable versions of their IP cores. Synthesizable cores are delivered in a hardware description language such as Verilog or VHDL, permitting customer modification (at the functional level). Both netlist and synthesizable cores are called 'soft cores', as both follow the SPR design-flow (synthesis, placement and route.)

Analog and mixed-signal logic generally require a lower-level, physical description. Hence, analog IP (SERDES, PLLs, DAC, ADC, etc.) are distributed in transistor-layout format (such as GDSII.) Digital IP-cores are sometimes offered in layout format, as well. Such cores, whether analog or digital, are called 'hard cores' (or hard macros), because the core's application function cannot be meaningfully modified by the customer. Transistor layouts must obey the target foundry's process design rules, and hence, hard cores delivered for one foundry's process cannot be easily ported to a different process or foundry. Merchant foundry operators (such as IBM, Fujitsu, Samsung, TI, etc.) offer a variety of hard-macro IP functions built for their own foundry process, helping to ensure customer lock-in.

For digital applications, soft cores and hard cores serve different roles. Soft-cores offer greater customer flexibility, while hard-cores, by the nature of their low-level representation, offer better predictability in terms of timing-performance and area.

IP cores in the electronic design industry have had a profound impact on the design of SoCs. The IP core can be described as being for chip design what a library is for computer programming or a discrete integrated circuit component is for printed circuit board design.

Vendors

There are vendors of IP hardware cores that solve a variety of problems faced by device designers. In practice, hardware designs are integrated into customer designs using standardized interconnect schemes. The value that these companies offer their customers is that they can save considerable design and testing time, reducing the time to market of end user appliances. For example, an MP3 player may use a previously designed MP3 codec as a drop in hardware module, freeing the MP3 player designers from having to implement the complex MPEG standards themselves.

Common IP cores such as soft microprocessors are available in a range from small 8-bit processors, such as the Intel 8051, to larger 32-bit processors such as the ARM7TDMI and MIPS32. Such processors form the brains of many embedded systems. Along with processors, IP cores are also available for a variety of controllers for peripherals such as LCD panels, AC97, network layers, and sensors.

Open source

There are open source providers of hardware cores. OpenCores.org offers a wide variety of designs, mostly written in VHDL and Verilog. All these cores are provided under the GPL or BSD-like licenses (see OpenCores licenses for details).