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EMAC Port Registers
5.40 Transmit Pacing Algorithm Test Register (TPACETEST)
The Transmit Pacing Algorithm Test Register (TPACETEST) is shown in Figure 68 and described in Table 68.
Figure 68. Transmit Pacing Algorithm Test Register (TPACETEST)
31 |
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| 16 |
| Reserved |
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15 | 5 | 4 | 0 |
Reserved |
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| PACEVAL |
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LEGEND: R = Read only;
Table 68. Transmit Pacing Algorithm Test Register (TPACETEST) Field Descriptions
Bit | Field | Value | Description |
Reserved | 0 | Reserved | |
PACEVAL |
| Pacing register current value. A nonzero value in this field indicates that transmit pacing is active. A | |
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| transmit frame collision or deferral causes PACEVAL to be loaded with 1Fh (31); good frame |
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| transmissions (with no collisions or deferrals) cause PACEVAL to be decremented down to 0. |
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| When PACEVAL is nonzero, the transmitter delays four Inter Packet Gaps between new frame |
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| transmissions after each successfully transmitted frame that had no deferrals or collisions. If a |
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| transmit frame is deferred or suffers a collision, the IPG time is not stretched to four times the |
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| normal value. Transmit pacing helps reduce capture effects, which improves overall network |
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| bandwidth. |
126 | Ethernet Media Access Controller (EMAC)/Management Data Input/Output (MDIO) | SPRU975B |