I2C Bus Data Rate Doubling via Clock Line Encoding
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Solution Overview
Problem
The Inter-Integrated Circuit (I2C) data communications interface struggles to achieve its theoretical bandwidth due to the use of passive drivers that often fail to meet rise time requirements, resulting in bus frequencies lower than the maximum possible speed.
Innovation Solution
The method involves transmitting an SDL data signal and an SCL data signal in parallel, where the SCL signal is encoded with bits having rise times less than or not less than a predefined threshold to represent different binary values, effectively doubling the data rate by utilizing the clock line as a data line.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If passive drivers are used in I2C interface, then device complexity is reduced, but data transmission rate decreases below theoretical bandwidth
Solution Approach 1:
The patent changes the parameter being used for data encoding from amplitude/voltage level alone to include rise time characteristics. By encoding data in the rise time parameter of clock transitions (fast rise time for one binary value, slow rise time for another), the system achieves higher data transmission rates without changing the fundamental passive driver architecture or increasing bus frequency.
2Productivity
If bus frequency is increased to achieve higher bandwidth, then data transmission rate improves, but compatibility with I2C standard decreases
Solution Approach 1:
Instead of increasing data transmission rate by moving to a higher dimension (increasing bus frequency), the patent exploits an underutilized dimension within the existing clock signal - the rise time characteristic of clock transitions. This allows encoding additional data bits in the temporal characteristic of the same frequency signal, effectively doubling the data rate while maintaining I2C standard compatibility.
3Ease of manufacture
If passive drivers are used, then ease of manufacture is improved, but rise time requirements are not met
Solution Approach 1:
The patent changes which parameter is used for data encoding - from relying on precise voltage rise times to utilizing rise time as an encoding dimension itself. This approach works well with passive drivers because it doesn't require them to meet stringent rise time specifications; instead, the rise time characteristics become part of the data encoding scheme, maintaining ease of manufacture while achieving higher data rates.
Data Source
AI summary
Increasing data transmission rate in an I2C system that includes an I2C source device and an destination device, the source device coupled to the destination device through an SDL and SCL, including: receiving in parallel, by the destination device, an SDL data signal and an SCL data signal, the SCL data signal encoded with bits; and, for each bit of the SCL data signal: detecting rise time of the bit and determining, in dependence upon the detected rise time, whether the bit represents a first binary value or a second binary value including: determining that the bit represents a first binary value when the detected rise time is less than a predefined threshold; and determining that the bit represents a second binary value when the detected rise time is not less than the predefined threshold.