3.4.6.5 WHAT IS THE DEFAULT INTERRUPT, WHERE IS IT DEFINED, AND
HOW DO I USE IT?
The “default interrupt” fills in the vector table when no other named vector exists. If it is
not defined, the compiler will create one that will halt in a debugging environment or
Reset in a normal execution (non-debug) environment.
You can define your own handler by simply defining an ISR named:
_DefaultInterrupt.