A system for delivering pulses of a desired mass of gas to a tool, comprising: a mass flow controller including flow sensor, a control valve and a dedicated controller configured and arranged to receive a recipe of a sequence of steps for opening and closing the control valve so as to deliver as sequence of gas pulses as a function of the recipe. The mass flow controller is configured and arranged so as to operate in either one of at least two modes: as a traditional mass flow controller (MFC) mode or in a pulse gas delivery (PGD) mode. Further, the mass flow controller includes an input configured to receive an input signal; an output configured to provide an output signal; a communication port configured to receive program instructions; memory configured and arranged to receive programming data determining the programmed configuration of the mass flow controller as either a digital or analog configuration; and a processor/controller for operating the mass flow controller in accordance with the programmed configuration.