With the default connections on the tn416 xplained nano board, the USB connection powers both the debug and target sections of the board. I will use this board in a one-off application but it will of course take power from the host appl machine. But I still want to be able to debug and update the appl in the tn416 target. The documentation implies that you can choose ONLY one of the other: power from USB or external power. So, if I use a local (external) power supply for the target section, how can I then use USB to connect to Atmel Studio? The power requirements, as I understand them, seem unreasonable.
"If other voltages are required, the kit must be disconnected from the USB to avoid damage or contention
to the USB power. The mEDBG must also be disconnected from the target section of the board. The
board can be powered by applying a voltage to one of the power connections on the board, according to
the table below. To avoid any power leakage through the mEDBG, this should also be disconnected by
removing the resistors shown in Figure 3-3."
I don't know what is meant by "other voltages". Other voltage sources, perhaps?
Looking at the schematics for the xplained board, it seems sufficient (and safe) to remove R100, supply the target end of the board with the local external 5v supply at VCC (pin 1 on the target section of the board), and then power the debugger when needed by plugging in the USB cable. The schematics pdf is attached.
Trial and error with power supplies is risky, so I am trying to make certain of my strategy first.
My question then is: Can I power the target section of the tn416 xplained board from a local machine power supply at the VCC pin, with R100 removed, and still connect USB for in-service maintenance?