Parameters are accessed with C4DAtom::GetParameter()/ C4DAtom::SetParameter(). See Parameter IDs.
Parameter: Enabled
FP_EMITTER_EMISSION_ENABLEDParameter: Start Frame
FP_EMITTER_EMISSION_STARTParameter: Emission Mode
FP_EMITTER_EMISSION_MODEParameter: Count
FP_EMITTER_EMISSION_SHOT_COUNTParameter: Rate
FP_EMITTER_EMISSION_CONSTANT_RATEParameter: Range
FP_EMITTER_EMISSION_CONSTANT_RANGEParameter: Duration
FP_EMITTER_EMISSION_CONSTANT_RANGE_DURATIONParameter: Pulse
FP_EMITTER_EMISSION_PULSE_COUNTParameter: Duration
FP_EMITTER_EMISSION_PULSE_DURATIONParameter: Gap
FP_EMITTER_EMISSION_PULSE_GAPParameter: Distribution
FP_EMITTER_EMISSION_PULSE_DISTRIBUTIONParameter: Continuous
FP_EMITTER_EMISSION_CONTINUOUSParameter: Seed
FP_EMITTER_EMISSION_SEED