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EMAC mac and phy address questions

yong zhang2
Expert 1305 points

Hi,guys:

I'm using the TMS570 board to communicate with the ETH, while I don't know why the MAC address  is 00:08:EE:03:A6:6C and the PHY address is 1 in the example, are there any rules to set the addresses?

I set the MAC address to 00:08:EE:03:A6:6D and the PHY address is 2, then a strange phenomenon happens, it seems that the packets loss rate(my program is just using the UDP send/receive functions) is higher than using the example addresses, how does it happen?

Another question about the Ethernet is that when I use two boards of the TMS570 connected to the same hub to send and receive packets each other, both boards have selected the CCM check function using the HCG like the picture ,  

while one board's mac and phy address using the example settings,the other's is the above, while at this time the phenomenon is when the two boards are powered(the same power), one of the two boards cannot entered the main function, only one of the boards can work properly and the one is random(first maybe the A board stops while when you powered again, maybe the second stops)(All these happens in the normal situation, without the emulator plugged in),the stopped program enters the while cycle of the CCMCheck function of the startup.c(plug the emulator and trace the program in th debug mode). When I do not select the CCM Self test, the two boards can enters to the main() functions properly, I do not know why the safety functions cannot pass as normal?

Hope you can help.

Regards,

yong

  • 0
    TI__Genius 13810 points

    Yong,

    I think MAC address is arbitary, you can put whatever you want.

    The PHY address, by default, should be '1' based on the default pull up and pull downs. If you want to use some value other than 1, you can:

    1. change the external pull resistors to automatically set it to other value during power up. or,

    2 use PHY address '1' at beginning, after modifying the PHY address, you should use the new PHY address to access the PHY from MCU MDIO.

    The CCM self test question is confusing. I don't think it is MAC related. If you only run the code on one board, do you still have the problem?

    Regards,

    Haixiao

  • 0 in reply to Haixiao Weng
    Expert 1305 points

    Thanks for your replying, you mean if the hardware design is the same with the HDK board, then the PHY address should be 1 no matter how many board were connected with the ETH?

    As for the CCM selftest, I'll confirm that whether it will still happen in one board, then come to you again.

    Regards,

    yong

  • 0 in reply to yong zhang2
    TI__Genius 13810 points

    Yes.

    PHy address specifies how/which address the MCU access the phy registers. You should not change it unless you use one MDIO to control several PHYs.

    Regards,

    Haixiao