This paper is based on instrumentation concepts and technologies, with emphasis on OCITM approaches developed by FS2 address embedded System-on-Chip debug. Strategically instrumentation based tools supplement In-Circuit Emulator (ICE), BDM, and JTAG based debug approaches and provide a number of advantages in larger multiprocessor embedded systems. On-Chip Instrumentation technology features including trace capabilities, and hardware event recognizers as will as methods of trace module integration and source-level debugger integration are discussed. Case studies are given for OCI integration with processor cores and in monitoring on-chip (AMBA) buses. Several examples of instrumentation applications using Function Tracing and Performance Analysis are presented. The paper concludes by discussing Emerging Trends in instrumentation, including Real-Time Data Exchange, Multi Chip debug, and NEXUS standards.