Increased integration has resulted in the creation of so called System-onChip (SoC) devices. They ~embed all the essential parts of an advanced computer into a single silicon chip in order to achieve compactness, reduced material cost, higher performance and lower power consumption. An adverse consequence of this integration is that the external interfaces once observed dUring debugging are now inaccessible within the chip, no longer aiding development. Debug support brings back this otherwise lost visibility by providing an observation window into the SoC, the heart of the overall system. Integration now enables SoCs to contain more than one processor core. which has made existing debug support strategies ineffective at supporting application development. Moreover. these existing single processor oriented debugging strategies fail to align with the circuit reuse based methodologies necessary to rapidly_ create new SoCs.This thesis presents a novel debugging strategy that fully encompasses the requirements of SoC creation and application development. The strategy enables realisation of advanced embedded systems that incorporate complex SoCs; devices containing multiple processor cores and other active cores. It achieves these advantages through a package of novel contributions.