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DP83822I: Question Related to PHY Link Status Pin

Rohidas Sawant76
Intellectual 370 points
Part Number: DP83822I


Hi,

I am using TI make PHY chip DP83822I in one of my design.

I want to read "PHY Link Status" in Microcontroller via firmware.

Question -> Whether this PHY has any Output Pin (GPIO or Interrupt Pin) to give "Link Status" ?

  • 0
    TI__Genius 16030 points

    Hello,

    LED_0 carries the link status. Kindly refer to datasheet for further programmability options on LED_0 pin.

    --

    Regards,

    Vikram

  • 0 in reply to Vikram Sharma
    Intellectual 370 points

    Thank you Vikram for the reply !

    I have one more Question ->

    We are using LED_0 port pin of PHY to drive the "LED" for Showing "Link Activity".

    Whether we can use this same pin to read PHY Link status also as you mentioned ? If yes. How ?

    Secondly, to read PHY control register bits via MDC and MDO interface may require some time to read PHY Link status.

    So, I am more interested in to provide the input port pin (Interrupt or GPIO pin) at microcontroller for reading PHY link status. And from the PHY side, it will be output pin (would be PHY interrupt pin) for PHY link status. 

    whether, above feature is there in this PHY ?

    Regards.

  • 0 in reply to Rohidas Sawant76
    Intellectual 370 points

    Hi  !

    Can anybody help me to resolve above issue ?

    Additional information ->

    we are using RMII mode. Whether the register "MII Interrupt Status Register #1 (MISR1)" is applicable for RMII mode ?

    In this register, they have 'Link Status Changed Enable' bit interrupt

    Can we use this for RMII mode and for Link down status?

  • 0 in reply to Rohidas Sawant76
    TI__Genius 16030 points

    Hello Rohidas,

    LED_0 should be sufficient to indicate the link status. Moreover by reading register 0x0001[2], you can get to know if link was down at any point of time before reading this bit. It is a latch low bit and if link would have gone down it would hold its bit value to be low till you read it. Only on second time read the bit will restore to one if link is active.

    Yes you can use MISR1 register also to check for the link going low during the run.

    After initial reply to the query, it is better to open a new query thread for new topics so that it can be tracked better.

    --

    Regards,

    Vikram