On-chip clock generator allowing rapid changes of on-chip clock frequency

摘要

A method and apparatus are provided, the method and apparatus comprising sending an output of a free-running counter to a comparator for a clock shaper logic unit, the free-running counter incremented every time a double-speed clock rises for an on-chip system and sending at least one input from a central processing unit (CPU) to the comparator for the clock shaper logic unit, the at least one input specifying a desired frequency. The method and apparatus also comprises producing a central processing unit (CPU) clock in the clock shaper logic unit based on the output of the free-running counter and the at least one input specifying the desired frequency by comparing a bit-reversed version of the output of the free-running counter with the at least one input specifying the desired frequency.