JTAG ICE User Guide

　　Congratulations on purchasing Atmel’s AVR? JTAG ICE. The JTAG ICE is a complete

　　tool for On-chip Debugging on all AVR 8-bit microcontrollers with the JTAG interface.

　　The JTAG interface is a 4-wire Test Access Port （TAP） controller that is compliant with

　　the IEEE 1149.1 standard. The IEEE standard was developed to enable a standard way

　　to efficiently test circuit board connectivity （Boundary Scan）。 Atmel AVR devices have

　　extended this functionality to include full Programming and On-chip Debugging support.

　　The JTAG ICE uses the standard JTAG interface to enable the user to do real-time

　　emulation of the microcontroller while it is running in the target system.

　　The AVR On-chip Debug protocol （AVROCD） gives the user complete control of the

　　internal resources of the AVR microcontroller. The JTAG ICE provides emulation capability at a fraction of the cost of traditional emulators.