What do the next sentences mean?
"Monitor mode entry can be achieved without use of the higher test voltage, VTST, as long as vector addresses $FFFE and $FFFF are blank, thus reducing the hardware requirements for in-circuit programming."
"Monitor mode entry without high voltage, VTST, if reset vector is blank ($FFFE and $FFFF contain
I understand that there's no need to put a high voltage VTST if those vector addresses are blank, but how do I know if they are blank? When do these addresses change? How do I check their state while my code is running?
The text belongs to "MC68HC908AP Family Data Sheet, Rev. 4"