Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See page_maxonapi_getting_started_foundations_cinema_parameters.
Parameter: Mode
GV_MONOFLOP_MODE
Parameter: Trigger
GV_MONOFLOP_TRIGGER
Parameter: Time
GV_MONOFLOP_TIME
Parameter: Duration
GV_MONOFLOP_DURATION
Parameter: Reset
GV_MONOFLOP_RESET
Parameter: Out
GV_MONOFLOP_OUT
Parameter: Count
GV_MONOFLOP_COUNT
Parameter: State
GV_MONOFLOP_STATE