An IP core is a complex functional block of electronic circuitry, the use of which is licensed to other companies by the original designer. It is generally a portion of a complete processor or other very complex integrated circuit. The design has usually been proven in a fully-tested product before it is licensed. IP cores are used by electronics engineers to quickly implement components of unique logic and chip designs. A memory controller, a three-dimensional graphics unit or even an entire processor may be an IP core.
When a company purchases a license for an IP core, it usually receives everything needed to design, test and utilize that core in its own product. The core design is often provided in a hardware description language, analogous to a computer software program. Logic and test patterns, as well as signal specifications, may also be provided. Any software needed, as well as design notes and documentation about known bugs, is usually included.
The rights purchased with an IP core often include the ability to alter it as needed for use in the purchaser's design. Modifiable cores are also known as soft cores because they are provided in Register Transfer Language (RTL) or as logic netlists. IP cores are sometimes provided in a low-level transistor layout format instead. These are called hard cores because they cannot be significantly modified by licensees. Many mixed-signal and analog designs are provided as hard cores to guarantee specific signal timing and physical layouts.
Some companies build their entire business around designing and licensing IP cores. For example, ARM Holdings processors appear in many mobile phones, Global Positioning System devices and Personal Digital Assistants. The company does not actually manufacture any chips; it simply licenses them as IP cores to many other chip makers. For other companies, IP cores are a final means of extracting profit from designs they no longer use in their own products. An IP core is also known as an intellectual property core because the owner can license the copyrights and patents of the core design to others.
An example of an IP core is the PowerPC® processor designed by a group of semiconductor manufacturers in 1991. This chip was heavily used as a stand-alone processor in Apple® Incorporated Macintosh® systems until 2005. It was also frequently used in servers and some video game systems. By 2006, Apple® had switched to Intel® Corporation chips and the PowerPC® was becoming more of a niche processor. Rather than abandon the architecture, the owners license it as an IP core to many other companies for use in their designs.
