A Retargetable Embedded In-Circuit Emulation Module for Microprocessors

This article presents an in-circuit emulation (ICE) module that can be embedded with a microprocessr core. The ICE module, based on the IEEE 1149.1 JTAG architecture, supports typical debugging and testing mechanisms, including boundary scan paths, partial scan paths, single stepping, internal resource monitoring and modification, breakpoint detection, and mode switching between debugging and normal modes. The architecture of the ICE module is parameterized and retargetable to different microprocessors. It has been successfully integrated with two microprocessors with significantly different architectures: one 8-bit industrial embedded microcontroller HT48x00 and one 32-bit ARM7-like embedded microprocessors. Both FPGA prototypes and chip implementation have been accomplished. Experiments show that real-time (on-line) debugging at full speed is possible with the embedded ICE at a minor gate count overhead.