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AM5718: DP83848M 10Base-T on autonego

Part Number: AM5718
Other Parts Discussed in Thread: DP83848M, DP83848C


I'm using SDK-LINUX-AM57X 06_03_00_106 on our custom board.

It has DP83848M PHY. The setting is as below.


root@am57xx-evm:~# ethtool eth0

Settings for eth0:
Supported ports: [ TP MII ]
Supported link modes: 100baseT/Full
Supported pause frame use: No
Supports auto-negotiation: Yes
Supported FEC modes: Not reported
Advertised link modes: 100baseT/Full
Advertised pause frame use: No
Advertised auto-negotiation: Yes
Advertised FEC modes: Not reported
Link partner advertised link modes: 10baseT/Half 10baseT/Full
100baseT/Half 100baseT/Full
Link partner advertised pause frame use: Symmetric
Link partner advertised auto-negotiation: Yes
Link partner advertised FEC modes: Not reported
Speed: 100Mb/s
Duplex: Full
Port: MII
Transceiver: internal
Auto-negotiation: on
Link detected: yes


Auto-negotiation is ON, and It is  linked up when connected to 100Base-TX hub.

But 10Base-T hub, linked down.(Both MDI and  MDI-X)

Please give me any advice.


Toshio Masuchi

  • Toshio, 

    Can you use the mdio-tool from:

    to read the PHY registers, see if you can:

    1. read the PHY registers

    2. if do, what is the link status. 


  • Hi Jian,

    Thanks for your reply.

    But I can't use the mdio-tool.

    'dmesg' shows as below.(pick up 'eth0','pruss1','DP83848')

    [ 8.090555] davinci_mdio 4b232400.mdio: phy[1]: device 4b232400.mdio:01, driver NS DP83848C 10/100 Mbps PHY
    [ 8.353360] prueth pruss1_eth: pruss_fw_drop_untagged_vlan 0
    [ 8.353368] prueth pruss1_eth: pruss MC Mask (Port 1) ff:ff:ff:ff:ff:ff
    [ 8.353865] prueth pruss1_eth: TI PRU ethernet (type 0) driver initialized
    [ 10.733389] remoteproc remoteproc4: Booting fw image ti-pruss/am57xx-pru1-prueth-fw.elf, size 7256
    [ 10.733520] pruss 4b200000.pruss: configured system_events[63-0] = 00600000,08a00000
    [ 10.733526] pruss 4b200000.pruss: configured intr_channels = 0x0000032a host_intr = 0x000002aa
    [ 10.740527] net eth0: started
    [ 12.802892] prueth pruss1_eth eth0: Link is Up - 100Mbps/Full - flow control off

    Please let me knoe if you notice anything.


    Toshio Masuchi


  • Toshio, 

    is there anyway you can test the the following:

    1. test if eth0 works with the 100Base-T hub in half-duplex mode

    2. read the actual status of the MDIO register on the PHY to understand what mode the PHY is in. The ethtool report may not be correct - it shows linked at 100Mbit/s yet you connected a 10Base-T hub. 

    We found an issue with half-duplex support for PRU software, on a different device that uses a later PRUSS. So likely the issue exists on AM57.