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TDA4VM: about QSGMII PHY out of reset via U-boot commands on evm board

jie nic
Prodigy 151 points
Part Number: TDA4VM

Hi：

I checked Enable8PortEth_J7EVM_SDK7p1_public.pdf，this document and found that QSGMII PHY out of reset via U-boot commands needs to set two GPIOs,

gpio set gpio@22_17;

gpio clear gpio@22_16,

what is the function of setting these two GPIOs? Combined with which two GPIOs are controlled on the schematic diagram of the TI EVM board?

Thanks,

Regards,

Jie

  • 0
    TI__Mastermind 23125 points

    Jie, 

    These GPIO controls in the u-boot are toggling the ENET_EXP_RESETz signal on the I2C GPIO EXPANDER2. You can find the schematics in the Common Processor Board diagram, then to the GSGMII daughter card schematics. The uboot driver comprehend I2C expander as a GPIO operation, that is why you see it as a GPIO command. 

    You can also manually execute these two lines in the uboot prompt, and see the LED lights up on the QSGMII daughter card, on the Ethernet jack. 

    regards

    Jian

  • 0 in reply to jian35385
    Prodigy 151 points

    Hi Jian，

    As you said above these GPIO operations are what control this ENET_EXP_RESETz signal ，

    but here are two gpio operations，how does it correspond？

    gpio set gpio@22_17;  ---->  ?

    gpio clear gpio@22_16, ----> ENET_EXP_RESETz low ?

    regards

    Jie