11.3.2 Hardware Related

Always switch off the target application power before switching off the Atmel AVR JTAGICE mkII. Never leave a powered-down JTAGICE mkII connected to a powered application as current may leak from the application and result in damage to the emulator.

If the target application uses the JTAG pins for general purpose I/O, the JTAGICE mkII can still be used to program the target via the JTAG pins (provided that the JTAG enable fuse is set.) However, be sure to connect the RESET pin of the target device to the nSRST pin of the emulator. Without this connection, the target application cannot be prevented from running after programming. If the application drives the JTAG pins as outputs, there will be signal contention with the emulator, which may result in damage to the emulator and/or target.