This is an IO view bug for UC3C in Atmel Studio 6.0 (SP2 as well). This is because of an error in the Part description file(s) for the UC3C devices.
A workaround for this issue is to update the XML file by hand, and replace this line:
<memory-segment rw=”RW” type=”io” size=”0x20000″ start=”0xfffe0000″ name=”IO”/>
<memory-segment rw=”RW” type=”io” size=”0x20000″ start=”0xFFFD0000″ name=”IO”/>
And delete these lines:
<memory-segment name=”HTOP0″ start=”0xFFFF0000″ size=”0x00007000″ type=”other”/>
<memory-segment name=”HTOP1″ start=”0xFFFE0000″ size=”0x00002400″ type=”other”/>
<memory-segment name=”HTOP2″ start=”0xFFFD0000″ size=”0x00002000″ type=”other”/>
(The XML files are located typically in c:\Program Files (x86)\Atmel\Atmel Studio 6.0\devices). If you have changed the installation path during installation then use that path and find for the folder devices.
After these changes, restart Atmel Studio 6.0 and try debugging.