High resolution timer using low resolution counter

摘要

Accurate measurement results can be obtained without increasing the number of bits of a timer. A timer 1 performs counting with low-speed clocks immediately after input pulse is inputted. When the value counted by the timer with the low-speed clock coincides with the set value of a switching set value register 4, high-speed clocks are inputted to the timer 1 by a clock switching circuit 6 which is switched by the output of a comparison circuit 5.