Figure 1. MDIO Register 0: SGMII Control Channels/Modules 1-3
| Bits | Name | Description | Attributes | Default Value |
|---|---|---|---|---|
| 0.15 | Reset |
1 = SGMII module 1-3 Reset 0 = Normal Operation |
read/write self clearing | 0 |
| 0.14 | Reserved | Returns what is written | read/write | 0 |
| 0.13 | Speed Selection (LSB) | Always returns a 0 for this bit. Together with bit 0.6, speed selection of 1000 Mb/s is identified. | returns 0 | 0 |
| 0.12 | Auto-Negotiation Enable |
1 = Enable SGMII Auto-Negotiation Process 0 = Disable SGMII Auto-Negotiation Process |
read/write | 1 |
| 0.11 | Reserved | Returns what is written | read/ write | 0 |
| 0.10 | Isolate |
1 = Electrically Isolate SGMII logic from GMII 0 = Normal operation |
read/write | 1 |
| 0.9 | Restart Auto- Negotiation |
1 = Restart Auto-Negotiation Process across SGMII link 0 = Normal Operation |
read/write self clearing | 0 |
| 0.8 | Duplex Mode | Always returns a 1 for this bit to signal Full-Duplex Mode | returns 1 | 1 |
| 0.7 | Collision Test | Always returns a 0 for this bit to disable COL test | returns 0 | 0 |
| 0.6 | Speed Selection (MSB) | Always returns a 1 for this bit. Together with bit 0.13, speed selection of 1000 Mb/s is identified. | returns 1 | 1 |
| 0.5 | Unidirectional Enable | Enable transmit regardless of whether a valid link has been established provided AN is disabled. | read/ write | 0 |
| 0.4:0.0 | Reserved | Always return 0s, writes ignored | returns 0s | 00000 |