Camera Controller Communication Channel Signal Level Switching
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Solution Overview
Problem
Existing camera systems face communication errors due to misidentification of interchangeable lenses compatible with conventional communication methods, leading to incorrect switching between communication methods, which disrupts data transmission between the camera body and lenses.
Innovation Solution
The implementation of a three-channel communication system with a clock/communication request channel, a first data communication channel, and a second data communication channel, allowing the camera controller to switch between communication methods and transmit specific signals for error restoration, ensuring reliable communication by maintaining the clock/communication request channel at a specific level.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the camera body switches to asynchronous communication method based on initial communication results, then communication speed is improved, but communication errors occur due to misidentification of lens compatibility
Solution Approach 1:
The camera body performs preliminary communication in the clock synchronous communication method before switching to asynchronous communication. This preliminary action allows the system to verify lens compatibility and establish proper communication parameters before transitioning to the faster asynchronous mode, preventing misidentification errors.
Solution Approach 2:
The system uses feedback from the initial clock synchronous communication to determine whether to switch to asynchronous communication. The communication control unit monitors communication results and adjusts the communication method accordingly, ensuring reliable operation while maximizing speed when appropriate.
2Device complexity
If the clock signal channel is used for multiple purposes including communication requests, then device complexity is reduced, but signal interpretation becomes ambiguous when communication errors occur
Solution Approach 1:
The communication protocol is segmented into distinct phases: initialization phase using clock synchronous communication, and data transmission phase using asynchronous communication. This segmentation allows the clock signal channel to have different meanings in different phases, resolving ambiguity while maintaining multi-functionality.
Solution Approach 2:
The function of the clock signal channel is dynamic rather than static. During initialization, it serves as both clock and communication channel; during data transmission, it serves only as clock signal while communication requests use separate data channels. This dynamic reassignment reduces complexity while preventing signal confusion.
Data Source
AI summary
The image-capturing apparatus communicates with an accessory apparatus using a clock/communication request channel and first and second data communication channels. The camera controller switches its communication method between a first communication method in which data communication is performed while a clock signal is alternately switched between first and second levels and a second communication method in which data communication is performed in response to a communication request from the camera controller to the accessory apparatus, which is output by switching a signal level of the clock/communication request channel from the first level to the second level. The camera controller, in response to detecting a communication error in the first and second communication methods, transmits to the accessory apparatus through the second data communication channel a specific signal for restoring the communication while keeping the signal level of the clock/communication request channel at the first level.