With a software-timed generation, software controls the rate at which data is generated. Software sends a separate command to the hardware to initiate each digital generation. In NI-DAQmx, software-timed generations are referred to as on-demand timing. Software-timed generations are also referred to as immediate or static operations. They are typically used for writing out a single value.
For software-timed generations, if any DO channel on a serial digital module is used in a hardware-timed task, no channels on that module can be used in a software-timed task.