8.2.155 GMAC MMSL Control Register
This register contains the control bits for the 802.3br MAC Merge Sublayer (MMSL).
| Name: | GMAC_MMSL_CR |
| Offset: | 0xF00 |
| Reset: | 0x00000020 |
| Property: | Read/Write |
| Bit | 31 | 30 | 29 | 28 | 27 | 26 | 25 | 24 | |
| Access | |||||||||
| Reset |
| Bit | 23 | 22 | 21 | 20 | 19 | 18 | 17 | 16 | |
| Access | |||||||||
| Reset |
| Bit | 15 | 14 | 13 | 12 | 11 | 10 | 9 | 8 | |
| Access | |||||||||
| Reset |
| Bit | 7 | 6 | 5 | 4 | 3 | 2 | 1 | 0 | |
| ROUTE_RX_TO_PMAC | RESTART_VER | PRE_ENABLE | VERIFY_DISABLE | ADD_FRAG_SIZE[1:0] | |||||
| Access | R/W | W | R/W | R/W | R/W | R/W | |||
| Reset | 1 | 0 | 0 | 0 | 0 | 0 | |||
Bit 5 – ROUTE_RX_TO_PMAC Route Received Frames to Preemptive MAC
| Value | Description |
|---|---|
| 0 | Routes all received frames to express MAC (eMAC). |
| 1 | Routes all received frames to preemptive MAC (pMAC). |
Bit 4 – RESTART_VER Restart the Verification Procedure (Write-only)
| Value | Description |
|---|---|
| 0 | No effect. |
| 1 | Restarts the verification procedure. Writing a one to this bit has no effect if any of the following are true: PRE_ENABLE=0, VERIFY_DISABLE=1 or the verification procedure is already in progress. When preemption is active, ROUTE_RX_TO_PMAC must be set to zero before writing to the RESTART_VER bit. This bit always returns zero when read. |
Bit 3 – PRE_ENABLE Preemption Operation Enable
| Value | Description |
|---|---|
| 0 | Disables the preemption operation and verifies mpackets will not be responded to or sent. If a preemption is in progress, the current preemption will complete and no further preemption will occur. |
| 1 | Enables the preemption by starting the verification procedure when VERIFY_DISABLE=0. Preemption can occur only once the verification process completes. If VERIFY_DISABLE=1, preemption can occur immediately. |
Bit 2 – VERIFY_DISABLE 802.3br Support Check for the Link Partner
| Value | Description |
|---|---|
| 0 | Enables the 802.3br support check for the link partner. |
| 1 | Disables the 802.3br support check for the link partner and preemption is enabled as soon as PRE_ENABLE=1. |
Bits 1:0 – ADD_FRAG_SIZE[1:0] PMAC Minimum Number of Bytes before Preemption
| Value | Name | Description |
|---|---|---|
| 0 | 64_BYTES | A minimum of 64 bytes can be sent by pMAC before any preemption. The value can be changed only when PRE_ENABLE is cleared. |
| 1 | 128_BYTES | A minimum of 128 bytes can be sent by pMAC before any preemption. The value can be changed only when PRE_ENABLE is cleared. |
| 2 | 192_BYTES | A minimum of 192 bytes can be sent by pMAC before any preemption. The value can be changed only when PRE_ENABLE is cleared. |
| 3 | 256_BYTES | A minimum of 256 bytes can be sent by pMAC before any preemption. The value can be changed only when PRE_ENABLE is cleared. |