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MCIMX6ULL-EVK custom with LAN8720A: can not interface with PHY addr=0

Question asked by nguyen hung on Apr 20, 2018
Latest reply on Apr 24, 2018 by nguyen hung

Hello guys,

I am building my own custom board based on MCIMX6ULL-EVK (MCIMX6ULL-EVK|i.MX6ULL Evaluation Kit|NXP)

As we knew that i.MX6ULL SoC used KSZ8081MNX/RNB (which come from Microchip Technology Inc) for physical layer.

In my custom board, I changed KSZ8081MNX/RNB to LAN8720A (which is from SMSC Inc)

one of the difference between KSZ8081MNX/RNB and LAN8720A is KSZ8081MNX/RNB has 3bits address(PHY[0:2]), but LAN8720A only has 1bit (PHY[0])

In my board,

            +ENET1 connected to LAN8720A' PHYAD0 pin connected to GND ==> PHY address=0

                  And then, I edited reg in imx6ull-14x14-evk.dts file (from reg = <2> to reg = <0>)

            +ENET2 connected to LAN8720A' PHYAD0 pin connected to VCC ==> PHY address=1

                  And then, I remained reg = <1> in imx6ull-14x14-evk.dts file

I briefed my hardware connection, PHY hardware-address, PHY software-address of both MCIMX6ULL-EVK from NXP and from me as following:

Result:

- MCIMX6ULL-EVK from NXP: working on both Ethernet (eth0 & eth1)

- But my board: ENET2 (addr=1) working on, but ENET1(addr=0) is not working

   + I configure them via "ifup" command, output looked as following:

         with ENET2 (eth0): interface eth0 already configured

         but with ENET1 (eth1): SIOCSIFFLAGS: No such device

Please give me good ideal for fixing it.

Thank very much. Good luck for you!

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