CCIe Bus Master Encoding Symbols on SCL and SDA Lines
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Solution Overview
Problem
The I2C bus, commonly used for connecting low-speed peripherals to processors, faces limitations in achieving higher bandwidths required for modern devices like mobile communications, where conventional protocols struggle to maintain compatibility with legacy devices and support enhanced data transfer rates.
Innovation Solution
The implementation of a Camera Control Interface (CCI) extension (CCIe) that operates on a two-wire, bi-directional, half-duplex serial interface, compatible with I2C bus operations, allowing for enhanced data transfer rates by encoding data as symbols on both the SCL and SDA lines, enabling CCIe devices to coexist with I2C devices and support multiple slaves with a single master, while embedding timing information in symbol transitions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If conventional I2C protocols are used to maintain compatibility with legacy devices, then device compatibility is improved, but data transfer rate is limited to 100 kbps or higher
Solution Approach 1:
The system dynamically switches between I2C mode and CCIe mode based on the communication partner. The CCIe master detects whether a slave device supports I2C or CCIe protocols and automatically selects the appropriate communication mode, enabling the same physical bus to operate at different speeds and protocols depending on the connected device's capabilities
Solution Approach 2:
The patent changes the operational parameters of the I2C bus by introducing CCIe mode with different signaling characteristics. In CCIe mode, the bus operates at higher data rates (up to 16.7 Mbps) with embedded clock signals and modified protocol parameters, while maintaining backward compatibility with legacy I2C devices that operate at lower rates
2Productivity
If data transfer rate is increased beyond conventional I2C limits, then bandwidth is improved, but protocol complexity increases
Solution Approach 1:
The CCIe master device is designed with multi-functionality, supporting both I2C and CCIe protocols on the same physical bus. This universal design allows a single master to communicate with both legacy I2C slaves and newer CCIe slaves without requiring separate hardware systems, thereby increasing productivity without proportionally increasing complexity
Solution Approach 2:
The CCIe master acts as an intermediary between legacy I2C devices and high-speed CCIe devices. It translates and adapts communication signals between the two protocols, enabling high-speed data transfer with CCIe devices while maintaining compatibility with legacy I2C devices, thus increasing bandwidth without requiring every device to support the complex CCIe protocol
3Productivity
If CCIe mode is implemented on existing I2C bus, then data transfer rate is improved, but device complexity increases
Solution Approach 1:
The communication system is segmented into two distinct modes (I2C mode and CCIe mode) that can be independently activated. The CCIe master and CCIe slave devices form a separate high-speed communication subsystem within the broader I2C bus architecture, allowing high-speed operations without affecting the simplicity of legacy I2C communications when CCIe devices are not involved
Data Source
AI summary
System, methods and apparatus are described that offer improved performance of a serial bus used for Inter-Integrated Circuit (I2C) and/or camera control interface (CCI) operations. CCI extension (CCIe) devices are described. CCIe devices may be configured as a bus master or as a slave. In one method, a CCIe transmitter may generate a transition number from a set of bits, convert the transition number into a sequence of symbols, and transmit the sequence of symbols in the signaling state of a two-wire serial bus. Timing information may be encoded in the transitions between symbols of consecutive pairs of symbols in the sequence of symbols. For example, each transition may cause a change in the signaling state of at least one wire of the two-wire serial bus. A CCIe receiver may derive a receive clock from the transitions in order to receive and decode the sequence of symbols.