Debugging Embedded and Real-Time Systems

7: On-chip debugging resources

Abstract

This chapter looks at the history and background for on-chip debugging resources. It examines the current protocols, such as background debug mode, or BDM, JTAG, Extended JTAG, and the IEEE 5001 Nexus standard.

Keywords

BDM; NEXUS; JTAG; On-chip debug; Bed-of-nails; ColdFire; Extended JTAG; MIPS; Ashling; SPEA

Introduction

It is hard to imagine debugging an embedded application without resources built into the processor core. Today, we take that for granted. In the early days of embedded applications, that wasn’t the case. Every transistor was precious, as was every I/O pin on a package. The thought of adding extra transistors to support the development process and then shipping these processors to ...