A method of programming a ring oscillator for use as a temperature sensor comprises selecting an initial number of delay elements for use in a ring oscillator. The method further comprise starting a system clock counter and counting pulses of the ring oscillator until the system clock counter reaches a programmed value. The method also comprises determining whether a number of counted ring oscillator pulses is between lower and upper count thresholds and changing the number of delay elements for the ring oscillator as a result of the number of counted ring oscillator pulses being less than the lower count threshold or greater than the upper count threshold.