Question: Can I attach a MiniProg3 programmer to a target board that will supply 9V on the MiniProg3 VTARG line?
The MiniProg3 includes over-voltage protection on all header connections. When connecting the MiniProg3 to external target boards, please do not connect to a voltage of over 9V, because this may damage the TVS protection diode on the VTARG line in the MiniProg3.
It is critical that you ensure a proper return path for the current through your board connection. You must ensure that both power and ground are connected through the MiniProg3 to your board, and the MiniProg3 VTARG connection is not left to float in an over- voltage situation.
The resistance to an over-voltage situation can be increased by ensuring that the VTARG line does not float above 9V, and that the MiniProg3 is connected to the PC during this time. If you follow these two guidelines, it will help ensure that the MiniProg3 is not damaged by accidently supplying more than 9V on the VTARG line.