| Bits | Description |
|---|---|
| 31:8 | Reserved |
| 7:0 | Preferred Protocol Version At speeds of 3,072.0 Mb/s and under and at 8,110.08, 10,137.6, 12,165.12, and 24,330.24 Mb/s, protocol version 1 is supported. At other speeds protocol versions 1 and 2 are supported. Default is protocol version 2. At line rates of 4,915.2, 6,144.0, and 9,830.4 Mb/s data scrambling is enabled when the protocol version on the link has been negotiated to version 2 and there is a non-zero value programmed into the Scrambler Seed register at address 0x12. To ensure correct operation it should be set before link initialization. Typically this is achieved by disabling the core through the line speed capability register. |
Recommended: It is strongly recommended that
scrambling is enabled at line rates of 4,915.2 Mb/s and over. At 8,110.08, 10,137.6,
12,165.12, and 24,330.24 Mb/s, scrambling is always enabled as part of the 64b/66b protocol.