JTAG, or Joint Test Action Group, is a standardized boundary-scan testing technique used in the field of electronics. It is a hardware interface employed to debug and test digital circuit boards or integrated circuits. JTAG is governed by the IEEE 1149.1 standard, which defines the behavior and functionality of the JTAG interface.
The primary purpose of JTAG is to provide a means to test electronic devices during the manufacturing process, ensuring their quality and reliability. It enables the testing of individual components and system interconnections by accessing the device's test access ports. JTAG is widely used in the development, production, and servicing of electronic devices, including embedded systems, microcontrollers, FPGAs (Field-Programmable Gate Arrays), and printed circuit boards.
JTAG utilizes a scan chain that connects multiple devices in a chain-like manner, allowing them to share a common test bus. This scan chain can be used to control and observe the internal states of each connected device, thereby enabling functional testing, boundary scan testing, and in-system programming. JTAG supports several modes of operation, such as instruction register, data register, bypass, and boundary scan modes, providing flexibility in testing and debugging electronic systems.
Apart from its testing capabilities, JTAG can also be utilized for programming and debugging purposes, enabling firmware updates and troubleshooting of hardware-related issues. Overall, JTAG plays a significant role in ensuring the quality and reliability of electronic devices by facilitating comprehensive testing and verification.
