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4.1.1. MAC Synchronous Clock Connections to Single Instance
4.1.2. MAC Synchronous Clock Connections to Multiple Instances
4.1.3. Clock Connections to MAC Asynchronous Operation
4.1.4. Clock Connections in PTP-Based Synchronous Operation
4.1.5. Clock Connections in Synchronous Ethernet Operation (Sync-E)
4.1.6. I/O PLL as System PLL
4.3.1.2. TX MAC Avalon Streaming Client Interface with Enabled Preamble Passthrough
When you turn on Preamble Passthrough in the parameter editor, you must provide 8 preamble bytes to the TX MAC interface.
The following table describes TX MAC field positions with enabled Preamble Passthrough parameter.
- MII Start of Packet control byte always replaces the first preamble byte.
- Bits [55:8] are the preamble bits, typically set to the 0x55 value.
- Bits [7:0] is the last preamble byte. In a standard preamble, it is set to the Start Frame Delimiter 0xD5 value.
i_tx_data | MAC Field | Description |
---|---|---|
[63:56]'' | Custom Preamble [63:56] | MII SOP control channel replaces it. |
[55:48]'' | Custom Preamble [55:48] | 0x55 |
[47:40]'' | Custom Preamble [47:40] | 0x55 |
[39:32]'' | Custom Preamble [39:32] | 0x55 |
[31:24]'' | Custom Preamble [31:24] | 0x55 |
[23:16]'' | Custom Preamble [23:16] | 0x55 |
[15:8]'' | Custom Preamble [15:8] | 0x55 |
[7:0]'' | Custom Preamble [7:0] | 0xD5 (SFD) |
[63:56]' | Dest Addr[47:40] | - |
[55:48]' | Dest Addr[39:32] | - |
[47:40]' | Dest Addr[31:24] | - |
[39:32]' | Dest Addr[23:16] | - |
[31:24]' | Dest Addr[15:8] | - |
[23:16]' | Dest Addr[7:0] | - |
[15:8]' | Src Addr[47:40] | When you turn on Source Address Insertion, contents are replaced by txmac_saddr unless i_tx_skip_crc is high. |
[7:0]' | Src Addr[39:32] | |
[63:56] | Src Addr[31:24] | |
[55:48] | Src Addr[23:16] | |
[47:40] | Src Addr[15:8] | |
[39:32] | Src Addr[7:0] | |
[31:24] | Length/Type[15:8] | - |
[23:16] | Length/Type[7:0] | - |
[15:0] | … | - |