Communication between the Atmel AVR ONE! main-board and the probe is done by LVDS signalling over the probe cable. The LVDS transceivers are connected to level translators that shift signals between the target's operating voltage and the internal voltage level on the AVR ONE!. The 'external' side of the level translators is connected physically to the target connector. The level translators are not powered directly from VTref, but from a buffered power source, which matches the VTref voltage. The JTAG channels can be operated in the range 1.65V to 5.5V up to 33MHz, while the AUX channels are capable of operating at up to 200MHz at 3.6V.
For best results it is recommended to correctly terminate the high-speed AUX signals on the target application PCB.
For further information on how to connect the probe to the target application, see section Connecting the AVR ONE!.