Device, operation-mode control method, and recording medium

An operation-mode control method implemented by a device having a plurality of power states, the operation-mode control method comprising:

• by a communication processing circuit, communicating with a communication destination device connected via a cable;
• by a confirmation-signal receiving circuit, receiving link pulses as a connection confirmation signal that is transmitted if being connected to the communication destination device via the cable;
• by a controller circuit, determining a power state of at least three power states depending on whether the confirmation-signal receiving circuit receives the connection confirmation signal;
• and
• by a power circuit, controlling supply of electric power to at least one of the communication processing circuit and the controller circuit in accordance with the power state determined by the controller circuit and a current power state of the device, wherein
• if the connection confirmation signal are not received in a first power state where electric power is supplied to the communication processing circuit and the controller circuit, a transition is made to a fourth power state where electric power is supplied to the communication processing circuit but no electric power is supplied to the controller circuit, and
• if a start-up request signal for starting up the device is received, via the cable while in the fourth power state, a transition is made to a power state where electric power is supplied to the controller circuit.

A non-transitory computer readable recording medium including a computer program that when executed by a controller circuit of an information processing device having a plurality of power states, causes the controller circuit to perform a method comprising:

• communicating, by a communication processing circuit of the information processing device, with a communication destination device connected via a cable;
• receiving, by a confirmation-signal receiving circuit of the information processing device, link pulses as a connection confirmation signal that is transmitted if being connected to the communication destination device via the cable;
• determining a power state states depending on whether the connection confirmation signal is received;
• and
• supplying electric power to at least one of a communication processing circuit and a controller circuit of the information processing device in accordance with the power state determined, wherein
• if the connection confirmation signal are not received in a first power state where electric power is supplied to the communication processing circuit and the controller circuit, a transition is made to a fourth power state where electric power is supplied to the communication processing circuit but no electric power is supplied to the controller circuit, and
• if a start-up request signal for starting up the information processing device is received, via the cable while in the fourth power state, a transition is made to a power state where electric power is supplied to the controller circuit.