The JTAG interface consists of a four-wire Test Access Port (TAP) controller that is compliant with the IEEE® 1149.1 standard. The IEEE standard was developed to provide an industry-standard way to efficiently test circuit board connectivity (Boundary Scan). Microchip AVR and SAM devices have extended this functionality to include full Programming and On-chip Debugging support.
To use this target interface with MPLAB X IDE, open the Project Properties window, “ICE 4” category, “Communications” option category, and select either “2-wire JTAG” or “4-wire JTAG”. See Emulator Options Selection.
Figure 1. JTAG Interface Basics
