A frequency dividing circuit and its control method is described. In this circuit, the frequency dividing input circuit is connected with a first counting circuit and a counting and setting circuit. The first counting circuit is connected with a second counting circuit, a first comparing circuit, a first threshold input circuit and the counting and setting circuit. The second counting circuit is connected with the counting and setting circuit, a second threshold input circuit and a second comparing circuit. The first comparing circuit is connected with the first threshold input circuit and the second comparing circuit. The second threshold input circuit is connected with the second comparing circuit. The second comparing circuit is connected with the counting and setting circuit. This method achieves frequency division by setting two thresholds and combining the output and input characteristics of comparator and counter by changing the dial switch without any circuit modification.
