ATmega4809 Xplained Pro has a 10-pin 50-mil AVR Debug Connector (J202) with UPDI that can be used to attach external debuggers to the ATmega4809. Microchip debugging tools like the Atmel-ICE and Power Debugger can connect directly to this connector.
| AVR® 10-Pin Debugger Connector Pin | Pin/Net | Function | Shared Functionality |
|---|---|---|---|
| 1 [TCK] | - | - | |
| 2 [GND] | GND | Ground | |
| 3 [TDO/UPDI] | UPDI | UPDI programming/debug | EDBG |
| 4 [VTG] | VCC_TARGET | ATmega4809 voltage | |
| 5 [TMS] | - | - | |
| 6 [nSRST] | PF6 | ATmega4809 reset signal | SW1, EXT1, EDBG |
| 7 [NC] | - | - | |
| 8 [nTRST] | - | - | |
| 9 [TDI] | - | - | |
| 10 [GND] | GND | Ground |