SNLA473 November 2024 DP83867CS , DP83867E , DP83867IS , DP83869HM , DP83TC811S-Q1 , DP83TC812S-Q1 , DP83TC813S-Q1 , DP83TC814S-Q1 , DP83TC817S-Q1 , DP83TC818S-Q1 , DP83TG720S-Q1 , DP83TG721S-Q1
For Single Pair Ethernet devices released after 2018, there are RX/TX packet counter and error counter registers that can be found in the data sheet. For example, in the DP83TG720S-Q1 these registers are 0x639-0x63E. Follow these steps to check communication in RX and TX direction:
Figure 1-7 shows an example of using DP83TC812's packet counter registers to check the RX and TX communication. The script ./packetcounters.sh prints out registers 0x639-0x63E in order. The register values indicate 10 packets are sent and 10 packets are received in the PHY and there are no errors. Therefore, RX and TX communication are working.
If an Ethernet PHY without packet counter registers is being used or the background packets cannot be disabled in the system, Wireshark or Tcpdump can be used to sniff the packets. Follow these steps to check communication in TX direction:
The steps for testing the RX direction are similar except the role of the link partner and DUT are reversed.