Abstract: A control unit is controlled by a computer having a reset input. A circuit configuration protects the operation of the control unit by placing a signal at the reset input for restarting the computer in the event of a malfunction. The circuit configuration includes a first register into which a predetermined bit pattern is written in read-only fashion; a second check register in which a single defined bit is set at a time after individual program routines have been executed; a counter timer; and a comparator connected to the first register, to the second check register and to the counter timer, for comparing contents of the second check register with contents of the first register and outputting a reload signal for reloading the counter timer if the contents match.