SNLA437A December 2023 – October 2025 DP83822H , DP83822HF , DP83822I , DP83822IF , DP83826I
In the default configuration, Auto-negotiation and Auto-MDIX can be enabled. A link pulse needs to be visible on the channel transmit (TD_P, TD_M) and will occasionally toggle to the receive pair (RD_P, RD_M). If set to MDI, this pulse is only available on the transmit pair while if set in MDI-X, this will only be available on the receive pair.
A short Ethernet cable with 100Ω terminations can be used for measuring the MDI signals. A terminated cable is shown in Figure 2-9. A connection diagram for making measurements with the terminated cable is shown in Figure 2-10.
Figure 2-9 100 Ω Terminated Cable for MDI Signal Measurement
Figure 2-10 Connection Diagram for 100 M Terminated CableLink pulses are nominally 100 ns wide and occur every 16 ms. Figure 2-11 shows a correct link pulse.