面向车身控制应用的8位MCU JTAG片上调试模块设计

基于IEEE 1149.1标准,设计了面向车身控制的8位MCU的JTAG片上调试系统。该系统很好地支持断点与观察点设置、外部调试请求、内存和存储器访问等基本调试功能。在几乎不改动内核的基础上,解决了内核中编码长度和执行周期不同的指令,给片上调试带来的困难和挑战,实现了单步调试、指令插入等功能。通过提出的方法,只需保护现场PC值,避免了一系列现场保护措施,减小了硬件实现代价。

Design of On-chip JTAG Debug Module of an 8 bit MCU for Body Control Module Applications

According to IEEE Standard 1149.1, this paper designs an on-chip JTAG debugging system for an 8 bit Body Control Module (BCM) MCU. The system supports basic debugging functions, including breakpoint and watches point setting, debug request, and access to registers and memory, etc. With hardly modifying the core, this paper resolves the challenge, which results from different instruction coding length and different running cycle, and achieves the functions of single-step and instruction-insertion. With the proposed method, the system does not need reserve any value but pc, reducing the hardware implementation cost.