A method for performing data access via software according to communication protocol handling includes: calculating a time slot period and an upper limit of a processing time for performing a predetermined data processing according to time slot information defined in a communication protocol, a critical period and a time slot number; defining a clock frequency of a processor according to the upper limit of the processing time; and performing data access according to the slot time by the processor operating at the clock frequency. Accordingly, design inflexibility arising from performing data access via hardware is addressed, and a non-real-time issue caused by performing data access via software is also prevented.