December 1, 2006 -- Ddebugging today refers to the process of understanding a program failure and removing the defective code. A failure includes any small deviation from the original intention, and removing the defective code is much better than adding correction code. In an ideal situation, all characteristics, such as bus and register values of a system, would be accessible at any time for monitoring and modification. But with ICs moving toward SOCs (systems on chips), accessibility becomes more difficult.

Debugging hardware is about providing as much access as possible to the internal resources of an embedded system, either through observing characteristics of the system, such as CPU states and PC values, or by changing system parameters. You can debug embedded systems in the early stages of design with simple techniques, such as logging and monitors, or you can use more recently developed methods for multicore SOCs, such as tracing, cache debugging, and cross-triggering. This article focuses not on how to write or debug the code, but on which embedded hardware IP (intellectual property) is available and which aspects of debugging this IP addresses.

By Bertrand Déléris. (Déléris is a systems-architect engineer at Freescale Semiconductor, Inc.)