Lens detection method and lens detection system used for detecting type of externally connected lens

A lens detection system comprising:

• a system chip comprising a first lens selection pin and a protocol path pin;
• a connector configured to connect an external lens and comprising a first connection port, a second connection port, a third connection port and a fourth connection port;
• and
• a first switch comprising a first terminal coupled to the second connection port of the connector, a second terminal coupled to the fourth connection port of the connector, a third terminal coupled to the first lens selection pin of the system chip, and a fourth terminal coupled to the protocol path pin of the system chip;
• wherein:
• the system chip is configured to enable the first lens selection pin and determine whether the protocol path pin receives a first lens identification code, and the first lens identification code is generated and sent to the system chip from the fourth terminal of the first switch when a loop is formed by the external lens and the second connection port and the fourth connection port of the connector;
• when system chip receives the first lens identification code, the system chip loads first lens data and enters a first lens operation mode for controlling a first lens;
• and
• when the system chip fails to receive the first lens identification code, the system chip disables the first lens selection pin.