Visible to Intel only — GUID: nik1409872178867
Ixiasoft
Visible to Intel only — GUID: nik1409872178867
Ixiasoft
1.2.2.1. Word Aligner
Parallel data at the input of the receiver PCS loses the word boundary of the upstream transmitter from the serial-to-parallel conversion in the deserializer. The word aligner provides word boundary restoration during link synchronization with the following four modes:
- Manual alignment mode
- Bit-slip mode
- Automatic synchronization state machine mode
- Deterministic latency state machine mode
The word aligner searches for a predefined alignment pattern in the deserialized data to identify the correct boundary and restores the word boundary during link synchronization. The alignment pattern is predefined for standard serial protocols according to the respective protocol specifications to achieve synchronization or you can specify the settings with a custom word alignment pattern for proprietary protocol implementations. Except for bit-slip mode, after completing word alignment, the deserialized data is synchronized to have the word alignment pattern at the LSB portion of the aligned data.
In addition to restoring the word boundary, the word aligner also supports optional features.
Feature | Availability |
---|---|
Programmable Run-Length Violation Detection | All transceiver configurations |
Receiver Polarity Inversion | All transceiver configurations except PCIe |
Receiver Bit Reversal | Custom single- and double-width configurations only |
Receiver Byte Reversal | Custom double-width configuration only |
The operation mode and alignment pattern length support varies depending on the word aligner configurations.
PCS Mode | PMA–PCS Interface Width | Word Aligner Mode | Alignment Pattern Length |
---|---|---|---|
Single Width | 8 bits | Manual alignment | 8 bits or 16 bits |
Bit-slip | – | ||
10 bits | Manual alignment | 7 or 10 bits | |
Bit-slip | – | ||
Automatic synchronization state machine | 7 or 10 bits 6 | ||
Deterministic latency state machine | 10 bits 7 | ||
Double Width | 16 bits | Manual alignment | 8, 16, or 32 bits |
Bit-slip | – | ||
20 bits | Manual alignment | 7, 10, 20, or 40 bits | |
Bit-slip | – | ||
Deterministic latency state machine | 10 bits 7 |
When the 8B/10B encoder/decoder is enabled, the word aligner detects both positive and negative disparities of the alignment pattern. For example, if you specify a /K28.5/ (b’0011111010) pattern as the comma, rx_patterndetect is asserted if b’0011111010 or b’1100000101 is detected in the incoming data.
Section Content
Word Aligner in Manual Alignment Mode
Bit-Slip Mode
Word Aligner in Automatic Synchronization State Machine Mode
Word Aligner in Deterministic Latency State Machine Mode
Programmable Run-Length Violation Detection
Receiver Polarity Inversion
Bit Reversal
Receiver Byte Reversal