A method for monitoring a frequency signal provided within a unit is disclosed. The method comprises a step of receiving one or more binary signal levels of a cycle signal (CLK) or a control signal (CS) from a communication interface (CLK, CS, MOSI, MISO), wherein the communication interface (CLK, CS, MOSI, MISO) is designed to transfer information according to a communication protocol. The method further comprises a step of providing the frequency signal in the unit and comparing the frequency signal to a temporal sequence of signal levels of the cycle signal (CLK) received by the communication interface (CLK, CS, MOSI, MISO) in order to obtain a comparison result or controlling a counter by the control signal (CS) and the frequency signal in order to obtain a counter status. Finally, the method according to the disclosure comprises a step of recognizing a predetermined quality of the frequency signal if the comparison result fulfills a predetermined criterion or if the counter status lies within a predetermined value range in order to monitor by the recognized quality of the frequency signal.