5.4.1 Atmel-ICE Main Board

Power is supplied to the Atmel-ICE from the USB bus, regulated to 3.3V by a step-down switch-mode regulator. The VTG pin is used as a reference input only, and a separate power supply feeds the variable-voltage side of the on-board level converters. At the heart of the Atmel-ICE main board is the Microchip AVR UC3 microcontroller AT32UC3A4256, which runs at between 1 MHz and 60 MHz 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 Atmel-ICE 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 Atmel-ICE. Also in the signal path are Zener overvoltage protection diodes, series termination resistors, inductive filters, and ESD protection diodes. All signal channels can be operated in the range 1.62V to 5.5V, although the Atmel-ICE hardware can not drive out a higher voltage than 5.0V. The maximum operating frequency varies according to the target interface in use.