External Supply; Disconnecting The Onboard Debugger - Microchip Technology ATmega4809 Curiosity Nano User Manual

Figure 3-3. Target Regulator Safe Operation Area
3.3.2

External Supply

ATmega4809 Curiosity Nano can be powered by an external voltage instead of the onboard target
regulator. When the Voltage Off (VOFF) pin is shorted to ground (GND) the onboard debugger firmware
disables the target regulator and it is safe to apply an external voltage to the VTG pin.
Applying an external voltage to the VTG pin without shorting VOFF to GND may cause
WARNING
permanent damage to the kit.
Absolute maximum external voltage is 5.5V for the level shifters onboard. Applying a higher
WARNING
voltage may cause permanent damage to the kit.
Programming, debugging, and data streaming is still possible while using external power: the debugger
and signal level shifters will be powered from the USB cable. Both regulators, the debugger, and the level
shifters are powered down when the USB cable is removed.
3.4

Disconnecting the Onboard Debugger

The block diagram below shows all connections between the debugger and the ATmega4809
microcontroller. The rounded boxes represent connections to the board edge on ATmega4809 Curiosity
Nano. The signal names are shown in
board.
©
2018 Microchip Technology Inc.
ATmega4809 Curiosity Nano
Figure 3-1 and printed in silkscreen on the bottom side of the
User Guide
Curiosity Nano
DS50002804A-page 11