Traditionally, the ISP is considered to be the final phase of BS test session and builds the foundation for the following functional tests [3]. The fundamental JTAG-based ISP solutions are proposed in [4], [5] and [6], that describe processorcontrolled test and processor-centric board test (PCBT). These methods are based on the use of functionality of microprocessor (uP) or microcontroller (uC) to access peripheral components outside the uP or uC at normal operational speed of the board. The attractiveness of PCBT-based solutions are very high due to the usage of existing DfT structures
without any modifications. Later in this paper, the formal characterization of ISP will be given in the terms from JTAG and PCBT methodology.