The frequency of a clock signal is compared to a predetermined range. If the measured frequency is outside the range, a system controller determines if a current operating state of the overall system allows for the internal clock to be adjusted back into compliance. If the controller determines that the current system state allows for the change, then a control signal to the internal clock signal source is changed by the smallest increment available, either to increase or decrease the frequency. If the internal clock signal is out of the desired range, and the system controller does not decide to modify the frequency, the controller may increase the size of the range by decreasing the lower bound and/or increasing the upper bound.