1. About the 25G Ethernet Intel FPGA IP
2. Getting Started
3. 25G Ethernet Intel FPGA IP Parameters
4. Functional Description
5. Reset
6. Interfaces and Signal Descriptions
7. Control, Status, and Statistics Register Descriptions
8. Debugging the Link
9. 25G Ethernet Stratix® 10 Intel® FPGA IP User Guide Archives
10. Document Revision History for the 25G Ethernet Stratix® 10 Intel® FPGA IP User Guide
6.1. TX MAC Interface to User Logic
6.2. RX MAC Interface to User Logic
6.3. Transceivers
6.4. Transceiver Reconfiguration Signals
6.5. Avalon® Memory-Mapped Management Interface
6.6. PHY Interface Signals
6.7. 1588 PTP Interface Signals
6.8. Miscellaneous Status and Debug Signals
6.9. Reset Signals
4.1.1. 25G Ethernet Intel FPGA IP Core TX MAC Datapath
The TX MAC module receives the client payload data with the destination and source addresses. It then adds, appends, or updates various header fields in accordance with the configuration specified. The MAC does not modify the destination address, the source address, or the payload received from the client. However, the TX MAC module adds a preamble, if the IP core is not configured to receive the preamble from user logic. It pads the payload of frames greater than eight bytes to satisfy the minimum Ethernet frame payload of 46 bytes. By default, the MAC inserts the CRC bytes. The TX MAC module inserts IDLE bytes to maintain an average IPG of 12.
Figure 13. Typical Client Frame at the Transmit InterfaceIllustrates the changes that the TX MAC makes to the client frame. This figure uses the following notational conventions:
- <p> = payload size, which is arbitrarily large
- <s> = number of padding bytes (0–46)
- <g> = number of IPG bytes
Figure 14. TX MAC Functions