Management controller and control method thereof

A management controller is coupled to a plurality of external devices. The management controller includes a control circuit and a transmission circuit. The control circuit generates a control signal according to a first counting value and a second counting value. The transmission circuit is coupled to the external devices. In response to the first counting value not being equal to a first target value, the transmission circuit enters a circulating mode according to the control signal. In the circulating mode, the transmission circuit triggers the external devices in order. In response to the second counting value not being equal to a second target value, the transmission circuit continues to operate in the circulating mode. In response to the second counting value being equal to the second target value, the transmission circuit exits the circulating mode.