Table 5-40 Switching Characteristics Over Recommended Operating Conditions for EMAC RGMII Transmit - RGMII_TXD[3:0], and RGMII_TXCTL - RGMII ID Mode(1)
NO. |
PARAMETER |
MIN |
MAX |
UNIT |
RGMII5 |
td(TXD-TXC) |
Delay time, TXD to TXC |
(0.25 × tc(TXC)) - 0.24 |
(0.25 × tc(TXC)) + 0.60 |
ns |
RGMII6 |
td(TXCTL-TXC) |
Delay time, TXCTL to TXC |
(0.25 × tc(TXC)) - 0.24 |
(0.25 × tc(TXC)) + 0.60 |
ns |
RGMII7 |
tt(TXD) |
Transition time, TXD |
|
0.75 |
|
RGMII8 |
tt(TXCTL) |
Transition time, TXCTL |
|
0.75 |
|
- PCB traces for RGMII_TXD[3:0] and RGMII_TXCTL should insert an additional 150ps of delay relative to the PCB trace delay of RGMII_TXC. This provides the expected output timing as defined by the RGMII specification for a transmitter operating in RGMII-ID timing mode. Timing analysis should be performed on this interface using actual timing requirements/characteristics of the attached RGMII PHY. In some cases, additional PCB delays may be required to provide proper timing margins.
For more information, see section Networking Subsystem (NSS) in chapter Peripherals of the Device TRM.