WATCH DOG TIMER DEVICE

PROBLEM TO BE SOLVED: To provide a watch dog timer device capable of utilizing an inexpensive watch dog timer IC without a stop function. SOLUTION: A clock generating part 4 for generating clock signals is connected to the watch dog timer IC 2 through a tri-state output buffer 5. The tri-state output buffer 5 is controlled by a CPU 1. Normally, the tri-state output buffer 5 does not allow the clock signals to pass therethrough, and only watch dog monitoring pulses outputted from the CPU 1 are inputted into the watch dog timer IC 2. While the CPU 1 performs a processing in which the watch dog monitoring pulses cannot be outputted, the clock signals outputted from the clock generating part 4 are passed through the tri-state output buffer 5 and inputted into the watch dog timer IC 2.