Embedded-Clock Single-Line Communication With Dynamic Data Thresholds
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Solution Overview
Problem
Existing communication systems between master and slave communication apparatuses are limited by the characteristics of the communication line, requiring a flexible solution to accommodate various line characteristics and ensure reliable data and clock recovery.
Innovation Solution
A slave communication apparatus with a clock recovering section and a data recovering section that dynamically sets threshold values based on signal levels, and a master communication apparatus with a signal generating section that embeds a clock in data signals using distinct signal levels, allowing for adaptable communication over a single communication line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single communication line is used for bidirectional communication between master and slave apparatuses, then the communication system structure is simplified, but the reliability of data and clock recovery deteriorates due to varying communication line characteristics
Solution Approach 1:
The slave communication apparatus dynamically adjusts the data threshold value based on the recovered data value. When the recovered data indicates a first data value, the data threshold is set to a first threshold value; when it indicates a second data value, the data threshold is set to a second threshold value. This dynamic adjustment compensates for signal level variations caused by different communication line characteristics, thereby maintaining reliable data recovery while using a simplified single-line structure.
Solution Approach 2:
The system changes the parameter (data threshold value) according to the state of the recovered data. The data recovering section sets different threshold values (first threshold value or second threshold value) based on whether the recovered data corresponds to a first or second data value. This parameter change enables the system to adapt to different signal levels caused by varying communication line characteristics without requiring multiple communication lines.
2Device complexity
If fixed threshold values are used for data recovery, then the device complexity is reduced, but the adaptability to different communication line characteristics deteriorates
Solution Approach 1:
Instead of using fixed threshold values, the data recovering section implements dynamic threshold selection based on the recovered data value. The system switches between a first data threshold value and a second data threshold value depending on whether the recovered data corresponds to a first or second data value. This dynamic approach enables adaptation to different communication line characteristics while maintaining relatively simple device architecture.
Solution Approach 2:
The data recovering section uses feedback from the clock recovering section's output (the recovered data value) to determine which data threshold value to apply. When the recovered data indicates a first data value, the system feeds back the selection of a first data threshold value; when it indicates a second data value, it feeds back the selection of a second data threshold value. This feedback mechanism enables automatic adaptation to different communication line characteristics.
Data Source
AI summary
A slave communication apparatus including a clock recovering section that recovers a clock signal from a transmission signal having a first signal value when the clock is a first level, a second signal value when the clock is a second level and data has a first data value, and a third signal value between the first and second signal values when the clock is the second level and the data has a second data value; and a data recovering section that recovers the data, wherein the data recovering section sets the data threshold value to be a first setting value between the second and third signal values in response to the recovered data having the second data value, and sets the data threshold value to be a second setting value between the first and third signal values in response to the recovered data having the first data value.