Two-Wire Interface Synchronization Using Short Preamble and Weak Pull-Up
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Solution Overview
Problem
Conventional two-wire interfaces, such as the MDIO interface, have a lengthy preamble that hinders synchronization recovery and consumes excessive power, making them inefficient for data transfer and error handling.
Innovation Solution
A two-wire interface system where the master component monitors the data wire for a predetermined sequence of consecutive bits to detect a shorter preamble, allowing synchronization recovery while reducing power consumption by using a weak pull-up resistor to maintain the data wire in a high impedance state during the preamble phase.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional two-wire interface uses a lengthy preamble for synchronization, then synchronization reliability is improved, but power consumption increases and data transfer efficiency deteriorates
Solution Approach 1:
The patent changes the parameter of preamble length from conventional lengthy sequences to a shortened sequence of only 5-15 bits. This parameter change reduces power consumption during the preamble phase while maintaining synchronization reliability through the use of a weak pull-up resistor that keeps the data line in a high-impedance state, allowing for efficient detection of the shortened preamble sequence.
2Reliability
If a conventional two-wire interface uses a lengthy preamble, then synchronization recovery is improved, but data transfer speed deteriorates
Solution Approach 1:
The patent changes the preamble length parameter to 5-15 bits, significantly reducing the time required for synchronization recovery. The weak pull-up resistor mechanism ensures that even with this shortened preamble, the system can reliably detect synchronization points and recover from loss of synchronization, thereby improving data transfer speed without sacrificing recovery capability.
3Measurement precision
If a conventional two-wire interface asserts the data line actively during preamble, then detection reliability is improved, but power consumption increases
Solution Approach 1:
The patent applies the self-service principle by using a weak pull-up resistor that automatically maintains the data line in a high-impedance state during the preamble phase without requiring active driving from the master component. This passive mechanism reduces power consumption while still enabling reliable detection of the shortened preamble sequence through the natural electrical characteristics of the resistor.
Data Source
AI summary
A two-wire interface in which upon determining that an operation is to be performed on a slave component, the master component monitors the data wire for a predetermined number of consecutive bits having a particular binary value. Upon detection such a sequence, the master component asserts a frame of a two-wire interface on the data wire. This detected predetermined number of consecutive bits will be considered to be the preamble. During at least some of the preamble phase, the master component is not asserting anything on the data wire. Instead, the data wire is pulled high (or low) by a weak pull-up (or pull-down) resistor. Furthermore, the frame is designed so that there are bits having a guaranteed binary value that is opposite what would be expected in the preamble, to thereby facilitate synchronization.