DSP系统的增强型JTAG接口.pdfVIP

第36 卷 第8 期 计 算 机 工 程 2010 年4 月 Vol.36 No.8 Computer Engineering April 2010 ·工程应用技术与实现· 文章编号：1000—3428(2010)08—0242—03 文献标识码：A 中图分类号：TN911.72 基于DSP 系统的增强型JTAG 接口 董大明，方勇华，熊 伟 (中国科学院安徽光学精密机械研究所通用光学定标与表征技术重点实验室，合肥 230031) 摘 要：针对通用 JTAG 端口不能在远距离对高速处理器进行仿真的问题，提出增强型 JTAG 接口方案。通过讨论高速处理器的 JTAG 端 口信号的特征和时序，定性分析 JTAG 接口不能用于远距离仿真的原因。对通用 JTAG 接口进行信号驱动以及信号完整性补偿，给出接口 的电路图和测试结果。实验结果表明，增强型 JTAG 接口可在 120 cm 外对高速处理器进行仿真。 关键词：数字信号处理器；高速处理器；仿真；JTAG 接口 Enhanced JTAG Interface Based on DSP Systems DONG Da-ming, FANG Yong-hua, XIONG Wei (Key Laboratory of Optical Calibration and Characterization, Anhui Institute of Optics and Fine Mechanics, Chinese Academy of Sciences, Hefei 230031) 【Abstract 】According to the problem that high-speed processors can not be emulated through common JTAG-interface in a long distance, enhanced JTAG interface is proposed. Several factors are analyzed quantitatively that relate to the failure of emulating the high-speed processors in a long distance, through the discussion of character and timing of JTAG-interface-signals. According to the conclusion, drivers and compensation of signal integrity are given to the signals of common JTAG interface. The circuit and test result of the design is also discussed. The results show high-speed processors can be emulated through enhanced JTAG-interface over 120 cm. 【Key words 】Digital Signal Processor(DSP); high-speed processor; emulation; JTAG interface 1 概述 2 JTAG 接口信号特性分析 JTAG 是 IEEE1149.1 规定的一种边界扫描协议，用于对 2.1 JTAG 接口信号的功能和状态分析 IC 器件的外部接口总线状态进行扫描。