Research On On-Chip Debug For Embeded System

In the process of developing embedded systems and designing chips, a novel debug scheme can help developers detect and correct design bugs faster to shorten the development cycle. This paper focuses on on-chip debug (OCD) scheme for embedded system in three ways, a general precise debug exception model, a software debugger and debug strategy for multiprocessor embedded systems.A general precise debug exception model based on pipeline is established with portability, which provides a strategy for on-chip debug by adding a precise debug exception generate and process mechanism, a segment of off-board debug memory and a fast transfer method through JTAG port. The implementation of this model on embedded processor RISC32E shows that it meets the requirement on observability, controllability, non-incursion and great efficiency of debug.With good compatibility, RISC32E can use a variety of third-party debuggers. However, the poor extendibility of these debuggers limits their applications. A debugger named as RDView is proposed to meet the need. RDview is divided into three layers: application layer, control layer and communication layer. Meanwhile, a module in RDView is employed to manage the debug memory efficiently according to RISC32's requirement. The experimental results show that RDView possesses better scalability and practicability.In great detail, this paper presents a debug strategy for Multiprocessor Embedded Systems (MESD) in two ways, computation and communication part. In detail, system-level TAP and trace monitor are added to exploit the debug characteristics for computation and communication part respectively. At last, a case study with one RISC32E core and two MD32 cores is demonstrated to validate the practicability of the MESD debug strategy and the reusability of RDView. The result shows that this debug strategy is reusable.