A debug port is a chip-level diagnostic interface (akin to a computer port) included in an integrated circuit to aid design, fabrication, development, bootstrapping, configuration, debugging, and post-sale in-system programming. In general terms, a debug port is not necessary for end-use function and is often hidden or disabled in finished products. Due to their high complexity, debug ports are nearly universal in microprocessors (CPUs) and microcontrollers (MCUs). These are discussed below.