Visible to Intel only — GUID: vgo1461030998512
Ixiasoft
2.8.1. Link Consistency
2.8.2. Data Rate
2.8.3. Reference Clock Frequency
2.8.4. Port Type
2.8.5. Self Synchronized Link Up
2.8.6. Scramble
2.8.7. Broadcast Mode
2.8.8. Lane Polarity and Order Reversal
2.8.9. Data Type
2.8.10. Packet Type
2.8.11. Flow Control Operation
2.8.12. Transmit/Receive FIFO Buffers
2.8.13. Data Integrity Protection: CRC
2.8.14. Transceiver Configuration
2.8.15. Error Handling
2.8.16. Optimizing the Implementation
Visible to Intel only — GUID: vgo1461030998512
Ixiasoft
2.8.6. Scramble
Scrambling the data eliminates repeating characters, which affect the EMI substantially at high data rates.
A linear feedback shift register (LSFR) is used as a pseudo-random number generator to scramble the data, using the following polynomial equation:
G(x) = X16 + X5 + X4 + X3 + 1
The transmitted bits are XORed with the output of the LFSR in the data stream. At the receiver, the data stream is again XORed with an identical scrambler to recover the original bits. To synchronize the transmitter to the receiver, the COM character initializes the LFSR with the initial seed of 0×FFFF XORed with the lane number (LN).