Asynchronous Serial Communications Programmer's Reference Manual (32022-90052)

122 Chapter6
Typeahead Mode
Working in Typeahead Mode
Typeahead Mode and Subsystem Break
When typeahead mode is active, the subsystem break character has
additional functionality when typeahead is used, regardless of whether
or not subsystem break is enabled. Receipt of the subsystem break
character causes all data in the typeahead buffer to be discarded. This
provides the user with a final chance to erase a previously typed
command. But this feature should be used with caution; subsystem
break does, after all, have its own function. Users who depend on this
method to flush the typeahead buffer may find themselves processing
undesired subsystem breaks if subsystem break is enabled.