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LAUNCHXL2-RM57L: Ethernet Signals CRO Measurement

Saravanakumar S93
Expert 1300 points
Part Number: LAUNCHXL2-RM57L
Other Parts Discussed in Thread: DP83630

Hi All,
Currently, we are trying for the TI example program using Launchpad XL2 RM57 <=> Launchpad XL2 RM57.
This board consists of DP83630 Ethernet PHY Transceiver IC. We are able to establish the physical & Link Layer.

Below are the configurations,
    # MII Mode with 100 Mbps with Internal reference Clock
    # ACT & LINK LEDS are ON
    # VCLK4=40MHz(or)75 MHz=> We are getting the same behaviour for the both the clock
    # Channel 0
    # BROADCAST addressing
    # MAC ADDRESS(Point to Point.There is no IP address configured as of now. Sending the packets in Broadcast MAC address)
    # Phy address=0x01 for the both the launchpad XL2-RM57

https://e2e.ti.com/support/interface/f/138/t/835939

As per Aniruddha feedback given in the above link,
             RX_ER high indicated that there was some invalid symbols received during the data transfer. 
             False Carrier and RX_ER can indicate towards a reference clock issue. 
Hence, we have taken the measurements in CRO. Does this captured signal behaviours are OK? Herewith I have attached my Transmit Code/Receive for the reference.

Regards,
S.Saravanakumar

ethernet.zip

  • 0
    TI__Guru**** 197126 points

    Do you connect 2 boards with crossover cable? How do you measure the speed?

  • 0 in reply to QJ Wang
    Expert 1300 points

    We have connected the 2 boards standard LAN cable(1:1). There is no cross over cable.

    We have taken the measurements in DP83630 IC pins directly.

    Regards,

    S.Saravanakumar

  • 0 in reply to Saravanakumar S93
    TI__Guru**** 197126 points

    Hello,

    If standard cable is used, MCU1 TX signals are connected to MCU2 TX signals. How do MCU2 receive the data from MCU1? 

    If you use external loopback, a ethernet loopback plug is needed to loop TX back to RX pins. I don't know how to measure the speed on PHY IC pins. Please check with interface team.

  • 0 in reply to QJ Wang
    Expert 1300 points

    Hi QJ Wang,

    Since, both the boards are same category. For the board to board communication, we have used the crossed Ethernet cable between 2nos of Launchpad XL2 RM57L. Also, we are not checking the EMAC Loopback functionality.

                 Launchpad XL2 RM57L is loaded with EMAC Transmit program(VCLK=40 MHz)

                 Launchpad XL2 RM57L is loaded with EMAC Receive program(VCLK=40 MHz)

    When we are reading the PHYSTS register(0x10) = 0x2915. This indicates that False carrier sense and Receive error latch problem even after crossed cable. Kindly let me know, your valuable feedback.

    Note: For crossed cable, we have TX+, TX-, RX+,RX- pins are available. Other pins are not connected.

    Regards,

    S.Saravanakumar

  • 0 in reply to Saravanakumar S93
    TI__Guru**** 197126 points

    If you use PHY loopback mode to loop TX packet back to RX, what is the value of PHYSTS register?

    Was the crossover cable make by your self? Please double check if TX+ <--> RX+, TX- <--> RX-