I've got a new board I'm trying to program. Running Studio 7, ICE firmware up to date, programming a ATmega 2560. The ICE shows up in the Device Programming window until I plug in the connector to the JTAG header, which disconnects the ICE.
The design is copied from a different board I made that works fine. The connections look the same: Gerbers show JTAG connected to same places on boath board, the voltages on the JTAG hearders are the same on both boards. There is a little difference in the noise (Noise on 5V and GND much lower on new board, but higher on the signal lines).
Center light is read on the ICE when JTAG cable disconnected. Green and red lights with Jtag cable. Same behavior on old working board and new non-working board.
Same thing happens with a second ICE (and a second new board), so It appears there is something wrong with the board, but I can't figure out what. Thinking it must have something to do with the noise. Suggestions for what to try?