Microprocessor programmable clock calibration system and method

A microprocessor programmable clock calibration device compares, in response to a calibration command from a programmable processor, turns on a normally off reference oscillator clock, compares the frequency of the reference oscillator clock with the frequency of a calibratable oscillator clock, turns off the reference oscillator clock and adjusts, in response to a difference in those frequencies, the frequency of the calibratable oscillator clock towards that of the reference oscillator clock.