IXF1104
7.3RGMII AC Timing Specification
Figure 37 and Table 48 provide RGMII interface timing parameters.
Figure 37. RGMII Interface Timing
TXC |
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(at Transmitter) |
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| TSkewT |
TD[3:0] | TD[3:0] | TD[7:4] |
TX_CTL[n] | TXEN | TXERR |
TXC
(at Receiver)
RXC
(at Transmitter)
TSkewT
RD[3:0] | RD[3:0] | RD[7:4] |
RX_CTL | RXDV | RXERR |
RXC
(at Receiver)
TSkewR
TSkewR
Table 48. RGMII Interface Timing Parameters
Symbol | Parameter | Min | Typ | Max | Unit | |
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TskewT | 0 | 500 | ps | |||
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TskewR | 1 | – | 2.8 | ns | ||
Tcyc | Clock Cycle Duration2 | 7.2 | 8 | 8.8 | ns | |
Duty_T | Duty Cycle for Gigabit2 | 45 | 50 | 55 | % | |
Duty_G | Duty Cycle for 10/100T3 | 40 | 50 | 60 | % | |
Tr/Tf | Rise/Fall Time | – | – | .75 | ns | |
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1. | This implies that PC board design requires clocks to be routed so that an additional trace delay of greater | |||||
| than 1.5 ns is added to the associated clock signal. |
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2. | For 10 Mbps and 100 Mbps Tcyc scales to 400 ns +/– 40 ns and 40 ns +/– 4 ns respectively. |
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3. | Duty cycle may be stretched/shrunk during speed changes or while transitioning to a received packet’s | |||||
| clock domain, as long as minimum duty cycle is not violated and stretching occurs for no more than three | |||||
| Tcyc of the lowest speed transitioned between. |
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140 | Datasheet |
Document Number: 278757
Revision Number: 007
Revision Date: March 25, 2004