| 摘要 |
PURPOSE:To drastically reduce load imposed on a CPU for performing communication and to make autofocusing speed higher by detecting the change of the state of accessory and changing the state of a communication line from the accessory to a camera. CONSTITUTION:Data communication between a lens control microcomputer 12 and a camera control microcomputer 31 is detected by the lens microcomputer 12 when a zoom signal 20 is changed, and the communication line DATA 2 is lowered to Lo. The camera microcomputer 31 detects this effect and respectively transmits a serial clock and a command for transmitting the change of the state to a lens through terminals CK and DATA 1. When the serial communication clock is transmitted specified number of times, the interruption of communication occurs in the lens microcomputer 12, which lowers the CK and transmits to the camera micocomputer 31 that communication analysis processing is being performed(BUSY). While the CK is Lo(in the middle of BUSY), the communication is not performed by the camera microcomputer 31. |
