Abstract: An electrical stepper motor comprises a magnetical rotor and at least two electromagnetical driving coils for causing rotation of the rotator. A method of detecting an operating condition of the as e.g. a stall state of the electrical stepper motor comprises the steps of connecting one contact pin (P, M) of at least one of the electromagnetical driving coils via a high-impedance resistor (R1, R2) to a defined voltage source during a non-activated state of the driving coil, detecting a voltage induced at the driving coil during the non-activated state and converting the detected voltage into a digital signal, and digitally analyzing the digital signal and deriving an operating condition of the rotor by evaluation of the signal waveform including positive and negative components of the signal.

Abstract: A method of calibrating a module whose operation is dependent upon a module clock signal, the method comprising: over each calibration period of a plurality of such periods, obtaining a measure of the frequency of an observed signal, the observed signal being the module clock signal or a clock signal generated based upon the module clock signal; influencing operation of the module in dependence upon the obtained measures so as to calibrate the module; and for each said calibration period, taking account of a position in time of the end of that calibration period relative to a particular feature of the observed signal and delaying the start of the following calibration period relative to a subsequent said particular feature of the observed signal in dependence upon that position.

Abstract: An electrical stepper motor comprises a magnetical rotor and at least two electromagnetical driving coils for causing rotation of the rotator. A method of detecting an operating condition of the as e.g. a stall state of the electrical stepper motor comprises the steps of connecting one contact pin (P, M) of at least one of the electromagnetical driving coils via a high-impedance resistor (R1, R2) to a defined voltage source during a non-activated state of the driving coil, detecting a voltage induced at the driving coil during the non-activated state and converting the detected voltage into a digital signal, and digitally analyzing the digital signal and deriving an operating condition of the rotor by evaluation of the signal waveform including positive and negative components of the signal.

Abstract: A method of calibrating a module whose operation is dependent upon a module clock signal, the method comprising: over each calibration period of a plurality of such periods, obtaining a measure of the frequency of an observed signal, the observed signal being the module clock signal or a clock signal generated based upon the module clock signal; influencing operation of the module in dependence upon the obtained measures so as to calibrate the module; and for each said calibration period, taking account of a position in time of the end of that calibration period relative to a particular feature of the observed signal and delaying the start of the following calibration period relative to a subsequent said particular feature of the observed signal in dependence upon that position.