Research And Implementation Of On-Chip Debugging Solution Based On EJTAG

With the continuous development of China’s integrated circuit technology, moreand more SoC chips,which are researched and developed independently by China,areappearing in the marketplace. The SoC CPU in this paper is one of such chips,and it ismainly used for digital TV,Set-top box equipment,network equipment,storage devicesand consumer electronic products market.The successful research and development ofthis SoC CPU Core indicates that China has a big breakthrough in microprocessordesign fields,and China no longer depends on foreign processors.However, for thisSoC CPU,there are only few manufacturers who choose to use it in their products.If aCPU wishes to be widely used, the development tools of it must be enough powerful.It means that CPU vendor must provide a stable toolchain.In the toolchain,thedebugger plays an especially important role. Because in the design and developmentprocess of the Embedded System, using a highly efficient and stable debugger canhelp to reduce the difficulty of the chip’s development and help programmers toquickly trace the bug,which greatly helps to shorten the development cycle of thechip.However, the research of the On-Chip Debugging technology is still in itsinfancy, at this point, this topic is of the significance.Firstly, this paper descripes the concept of the remote debugging in embeddeddevelopment environment.And secondly, this paper introduces the different kind ofdebugging solutions in current field of Embedded System, for example, there aresoftware simulation debugging solution、software stub debugging solution、ICEdebugging solution and On-Chip Debugging solution.This paper is mainly on theresearch of On-Chip Debugging technology about SoC CPU, so a depth study is madeon this SoC CPU’s architecture, the handling of the debug exception and thememory-mapped when processor is in debug mode. Besides that, this paper alsocarries out a detailed description about the principle of the EJTAG, because this SoCCPU supports the On-Chip Debugging by using the EJTAG in its internal.After studying the hardware knowledge about the On-Chip Debugging, GDB is choosed todo the source-level debugging on the host side. On the basis of research on the GDBremote debugging protocol RSP, this paper implements a debugging agent whichnames gdb server to support the On-Chip Debugging. Accordingly, this paperachieves a low-cost On-Chip Debugging solution which supports the source-leveldebugging.