PCI Express Byte Skew Compensation Using Skip Symbols
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Solution Overview
Problem
Conventional PCI Express bus systems face challenges in compensating for byte skew at high-speed data transmission, as existing methods relying solely on comma symbols are inadequate due to variations in alignment caused by skip symbols during data transmission.
Innovation Solution
A method and device for a PCI Express physical layer receiver that adjusts the alignment point by reflecting the addition or removal of skip symbols, using a serializer/deserializer and Physical Layer Device (PHY) Interface to effectively compensate for byte skew between lanes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional byte skew compensation using only comma symbols is used, then the alignment process is simple, but the compensation accuracy deteriorates due to variations caused by skip symbols
Solution Approach 1:
The invention changes the parameter used for alignment from solely comma symbols to a combination of comma symbols and skip symbols. By detecting both types of symbols and calculating alignment points based on their combined positions, the system achieves more accurate byte skew compensation while maintaining a manageable alignment process.
2Productivity
If high-speed data transmission is implemented, then transmission efficiency is improved, but byte skew between lanes increases beyond 8-bit range
Solution Approach 1:
The invention extends the alignment approach from bit-level (within 8-bit range) to byte-level (beyond 8-bit range). By detecting skip symbols that span multiple bytes and calculating alignment points across the byte dimension, the system can compensate for larger byte skew variations that occur at high transmission speeds.
3Adaptability or versatility
If skip symbols are added or removed during data transmission, then data flow control is improved, but alignment point accuracy deteriorates
Solution Approach 1:
The invention introduces feedback by continuously detecting both comma symbols and skip symbols, monitoring their positions, and dynamically adjusting alignment point calculations based on the detected symbol patterns. This feedback mechanism allows the system to maintain accurate alignment despite the dynamic addition or removal of skip symbols for data flow control.
Data Source
AI summary
A method of compensating for a byte skew of a PCI Express bus, the method including determining whether received data are in a training sequence or not, setting an alignment point corresponding to each of the lanes based on a comma symbol included in the training sequence when the received data are in the training sequence, and shifting the alignment point by reflecting an addition or a removal of a skip symbol on the received data through each of the four lanes when the received data are not in the training sequence. Therefore, the byte skew of the PCI Express bus may be effectively compensated for despite the addition or the removal of the skip symbol.