Using the Embedded Debugger on the ATmega328P Xplained Mini board to debug the ATmega328P via debugWIRE.
If debug mode is not exited by selecting “Disable debugWIRE and Close” in the Debug menu, the DWEN fuse will be enabled, and the target will still be in debug mode, i.e., it will not be possible to program the target using ISP.
If any other CPU CLK than the external CLK supplied by the mEDBG is used, the debugWIRE is not guaranteed to work.
Applying a signal to J202/RESET (the RESET_SENSE signal) while debugging may result in unexpected behavior. This signal is NOT available during a debugging session because the RESET line is actively used by the debugWIRE interface.