A reference clock signal of at least one module clock signal associated with each module is delivered. A measurement period is generated and a module whose consumption is to be determined is selected. The frequency of the at least one module clock signal associated with the selected module reduced during the measurement period. A measurement of a first consumption of the device is made in the measurement period. A measurement of a second consumption of the device is made outside the measurement period. The consumption of the selected module is determined from the first and measured first and second consumptions.