研究了用于检验硅后芯片的硅后调试技术,考虑到现有的硅后调试技术缺乏实时监测芯片内部运行状态的能力,导致故障诊断的结果很不准确,提出一种基于扫描链的新的可编程片上调试系统。该系统充分利用芯片的片上传输总线,通过添加极少的硬件电路,使芯片能够实时监测自身的运行状态,并在满足程序设定的条件后,自动触发故障诊断模式。该系统充分利用芯片内建扫描链,通过控制扫描链实现对芯片内部状态精确配置和观测。此外,该系统通过片上时钟电路对调试时钟进行精确控制,保证各模式时钟切换的正确性,同时还支持实速测试,为时序分析和调试提供新途径。该系统已在最新一款龙芯高性能通用处理器芯片上得到成功应用。
The post-silicon debug for testing of post-silicon chips was studied, and a novel programmable on-chip debug system based on scan chain was put forward to change the present situation that current debug techniques are inaccurate in fault diagnosis because they lack the ability to perform the real-time monitoring of a chip' s internal operation state. The new debug system makes full use of the on-chip transmission bus and adds a few hardware circuits, so it can make a chip realize the real-time test of its operation state. Meanwhile, it automatically triggers the fault diagnosis mode when the programmable conditions are met. By making full use of scan chains, it can accurately configure and observe the internal state of the chip. Moreover, the system uses the on-chip clock circuit to ensure accurate clock switching and support the at-speed test for providing a powerful function for timing analysis and debugging. The system is successfully applied to the development of the latest Loongson high performance micropro- cessor.