Control device and diagnosis-information recording/displaying device

A control device with a first general-purpose interface comprising a power-supply pin, a ground pin, and a data pin to be connected with an external device, the control device comprising:

• a diagnosis-information output circuit that includes
• a condition monitoring circuit that receives and holds diagnostic signals required for diagnosis of an operation condition of the control device,
• a condition determining circuit that determines a condition of the control device based on the diagnostic signals held by the condition monitoring circuit,
• a condition-controlling-signal monitoring circuit that outputs a control signal for controlling the control device in response to an external signal required for controlling the control device from outside of the control device,
• an output-information generating circuit that generates diagnosis information indicating the condition of the control device based on a condition determination result by the condition determining circuit and the control signal received from the condition-controlling-signal monitoring circuit,
• a first output circuit that converts the diagnosis information generated by the output-information generating circuit into an electrical signal representing the diagnosis information and outputs the electrical signal, and
• a condition controlling circuit that changes a signal in the control device in response to the control signal, wherein
• the control device outputs the electrical signal output from the first output circuit to outside of the control device via the power-supply pin and/or the ground pin included in the first general-purpose interface, and receives the external signal from outside of the control device via the power-supply pin and/or the ground pin included in the first general-purpose interface to change the control signal in the control device.