Semiconductor data processing apparatus and engine control apparatus

The reliability in detection of toothless part is improved. A first counter (102) counts a clock signal from an initial value for each of pulse intervals of a predetermined event pulse train and the count value of the first counter (102) is held in a register (105) for each of pulse intervals. Further, the second counter (103) counts the clock signal from an initial value so that the count value thereof is equal to plural times of the count value of the first counter (102) for each of the pulse intervals. A timer function which can detect any of a first state in which the count value of the first counter (102) is equal to or larger than a first reference value and a second state in which the count value of the second counter (103) is equal to or smaller than the value held in the register (105) for each of the pulse intervals is adopted.