Remote Debugging of Raspberry Pi with JTAG interface

This paper discusses the JTAG (Join Test Action Group) standard and its use to obtain debug information from circuits and chips. This standard describes a protocol that gives the access to a very low-level outputs from the chips where this technology is enabled. The main described scenario is using this protocol on a Raspberry Pi (RPi) board. In particular, it comes with an ARM (Acorn RISC Machine, RISC reduced instruction set computing) processor, and the ARM processor family has become dominant in the modern computing, especially with the wide usage of smartphones. Thus, understanding how a low-level debugging can be performed on this machine gives an important experience for anyone interested in embedded systems development. Another significant part of the paper is designated to debugging Linux kernel on RPi . It is not possible to run Windows natively on ARM processors, so Linux is the most popular general purpose OS (Operating System) for RPi. The Linux kernel real-time debugging is of a great interest as well. JTAG debugging is not enabled by default on RPi. Providing a way to enable JTAG on RPi in order to debug a Linux kernel is the main goal of the paper.