When a mobile device receives an incoming call from a telephone number: it identifies a number of digits associated with the telephone number and determines whether the number of digits exceeds a threshold. In particular, the method generally comprises steps of detecting a hardware library when compiling a software program for the programmable logic device; and accessing hardware module information stored in the hardware library; inserting the hardware module information of the hardware library into a reference platform. It likewise has a voltage level detector which operates at the second supply voltage and is coupled to the voltage level shifting unit and which can be supplied with the first supply voltage, and which is set up such that it outputs a first control signal if the voltage level of the first supply voltage is below a threshold value.