说明：  这篇文章主要介绍ARM JTAG调试的基本原理。基本的内容包括了TAP (TEST ACCESS PORT) 和BOUNDARY-SCAN ARCHITECTURE的介绍，在此基础上，结合ARM7TDMI详细介绍了的JTAG调试原理。
(This article introduces the ARM JTAG debugging basic tenets. The basic elements include the TAP (TEST PORT ACCESS) and BOUNDARY- SCAN ARCHITECTURE presentation on this basis, the combined ARM7TDMI details of the principles of JTAG debugging.)