See the blog post at : http://blog.arduino.cc/2014/05/15/meet-arduino-zero/
Support for debugging a running microcontroller has been available for competing developer kits for a while now :
- NXP has it for the many LPCXpresso boards,
- some developer boards have a Segger J-Link on board.
- The TI evaluation kits like the Tiva Launchpad have and “On-board In-Circuit Debug Interface (ICDI)” which is more or less open.
- Some Freescale boards have OpenSDA.
- The ST NUCLEO-F401RE uses ST-LINK
I’m curious how Arduino.cc will integrate the debugger in the Arduino IDE.