4.5.1 Operation at Other Voltages

The ATmega4809 Xplained Pro board is operated at 3.3V or 5.0V by default but it also has the possibility of running at other voltages from an external supply.

All signals between the EDBG and the ATmega4809 are level-shifted through level shifters compatible with supply voltages from 1.65V to 5.5V.

To supply an external voltage:

  1. Remove the voltage selection jumper from the power select header J105.
  2. Check that the external voltage is within the specification of on-board and connected peripherals.
  3. Supply the external voltage to the center pin (pin 2) of J105 (do not forget ground).
  4. Plug in the EDBG USB cable.
Info: The ATmega4809 can be powered from 1.8V to 5.5V, remember to check the voltage range of any parts soldered on the CryptoAuthentication footprint.
Info: The EDBG checks the voltage at J105 pin 2 when USB power is applied. If the voltage is between 1.6V to 5.5V, and not higher than the maximum supported voltage of any connected Xplained Pro extension power is applied to the ATmega4809, Xplained Pro extension headers, and the CryptoAuthentication footprint. To bypass this voltage, check connect the external voltage to J100 pin 4, instead of J105 pin 2.
CAUTION: Applying power directly to J100 pin 4, which is outside the limits of the board may cause permanent damage.
CAUTION: 3.3V and 5.0V is connected directly to the mikroBUS socket on the board. These voltages will not follow the externally supplied voltage.