I have a custom PCB using an Atmega16U2 and i'm connecting it to my PC directly via USB. When I program the uC I do so via Atmel FLIP over the USB port I designed into my PCB.
The problem: I have the below pinout on board for debugging via debugWire.
Since I don't have the MOSI, SCK, and MISO pins needed for SPI comms over this interface it seems that my Atmel ICE is unable to program the DWEN fuse to enter debugging mode. I see the following dialogs when I try to Start Debugging and Break from Atmel Studio:
Is it impossible to debug given my pinout that doesn't have SPI pins? If not, how do I program the DWEN fuse?