Even though there is an on-board debugger, external debuggers can be
connected directly to the ATmega4809 Curiosity Nano to program/debug the ATmega4809. The on-board debugger keeps all the pins
connected to the ATmega4809 and board edge in tri-state
when not actively used. Therefore, the on-board debugger will not interfere with any
external debug tools.
Figure 1. Connecting the MPLAB®PICkit™ 4 In-Circuit Debugger/Programmer to ATmega4809 Curiosity Nano![](GUID-D9EA1CA2-7F93-4AAF-9518-EFAF35EB3E6A-low.png)
Figure 2. Connecting the Atmel-ICE to ATmega4809 Curiosity Nano![](GUID-93F776B8-55DE-420A-ABFC-7AF9E7E26AB8-low.png)
CAUTION: To avoid contention
between the external debugger and the on-board debugger, do not start any
programming/debug operation with the on-board debugger through MPLAB® X IDE or Atmel Studio 7 or mass storage programming
while the external tool is active.