Low Latency E-Tile 40G Ethernet Intel® FPGA IP User Guide
Visible to Intel only — GUID: ljw1473709807227
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Visible to Intel only — GUID: ljw1473709807227
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4.1.2.2. IP Core Strict SFD Checking
The Low Latency E-Tile 40G Ethernet core RX MAC checks all incoming packets for a correct Start byte (0xFB). If you turn on Enable Strict SFD check in the Low Latency E-Tile 40G Ethernet parameter editor, you enable the RX MAC to check the incoming preamble and SFD for the following values:
- SFD = 0xD5
- Preamble = 0x555555555555
The RX MAC checks one or both of these values depending on the values in bits [4:3] of the RXMAC_CONTROL register at offset 0x50A.
Enable Strict SFD check | 0x50A[4]: Preamble Check | 0x50A[3]: SFD Check | Fields Checked | Behavior if Check Fails |
---|---|---|---|---|
Off | Don't Care | Don't Care | Start byte | IP core does not recognize a malformed Start byte as a Start byte |
On | 0 | 0 | Start byte | |
0 | 1 | Start byte and SFD | IP Core drops the packet | |
1 | 0 | Start byte and preamble | ||
1 | 1 | Start byte and preamble and SFD |