5.4.1 Atmel JTAGICE3 Main Board

Power is supplied to the Atmel JTAGICE3 from the USB bus, regulated to 3.3V by a step-down switch-mode regulator. A small amount of power (less than 1mA) is also drawn from the target application by the VTG pin, and is used to power the variable-voltage side of the on-board level converters. At the heart of the JTAGICE3 main board is the Atmel AVR UC3 microcontroller AT32UC3A3256, which runs at between 1MHz and 60MHz depending on the tasks being processed. The microcontroller includes an on-chip USB 2.0 high-speed module, allowing high data throughput to and from the debugger.

Communication between the JTAGICE3 and the target device is done through a bank of level converters that shift signals between the target's operating voltage and the internal voltage level on the JTAGICE3. Also in the signal path are series termination resistors and ESD protection diodes. All signal channels can be operated in the range 1.65V to 5.5V. Maximum operating frequency varies according to the target interface in use.