JTAG是一种通过ARM芯片的JTAG边界扫描进行调试的仿真设备。它采用TMS、TDI、TCK与ARM内核通信，不占用MCU的其他资源，比在线实时仿真器要[便宜、简单，便于自制。-JTAG is an ARM chip through the JTAG boundary scan debug the simulation equipment. It uses TMS, TDI, TCK and the ARM core communications, the MCU is not occupied by other resources than the online real-time simulator to [cheap, simple, easy home-made.