MAC Configuration Register
| RE | Receiver Enable |
| TE | Transmitter Enable |
| DC | Deferral Check |
| BL | Back-off Limit |
| ACS | Automatic Pad/CRC Stripping |
| LUD | Link Up/Down in RGMII |
| DR | Disable Retry |
| IPC | Checksum Offload |
| DM | Duplex mode |
| LM | Loop-back Mode |
| DO | Disable Receive Own |
| FES | Speed |
| PS | Port Select |
| DCRS | Disable Carrier Sense During Transaction |
| IFG | Inter-Frame GAP |
| JE | Jumbo Frame Enable |
| BE | Frame Burst Enable |
| JD | Jabber Disable |
| WD | Watchdog Disable |
| TC | Transmit Configuration in RGMII |
| CST | CRC stripping for Type frames |