DP83822IF: LED_1 / SD option

Part Number: DP83822IF

HI ,

In the DP83822 , The LED_1 and SD pins are multiplexed and in the data sheet TI recommends to use it in the SD function for Fiber mode . We need to have two LED indications 1: Link Quality and 2 : Tx/RX activity .

If we use the SD pin as signal detect how can we get the Activity LED function .

Regrads

Eby

  • Hi Eby,

    Thanks for getting in touch with us.

    You can play around the registers 0x0462, 0x463, 0x0025 to get what you need. The descriptions are available in the datasheet.

    In summary,
    You can use COL pin as another LED and use it to show activity.
    If COL is used, you can mux both link ok and activity onto the LED_0 pin (LED is high when link is OK, LED blinks when activity is present).

    Please let me know if you need more details.

    --
    Regards,
    Gokul.

  • Hi,

    If we use COL pin to drive TX/RX activity LED. Can you please clarify if there is  any issues/impact in software if we are not using COL pin for collision detection while in Half duplex operation ?Is the communication standard allowed this?

    Regards

    Eby

  • Hi Eby,

    COL is used by some of the MACs in MII mode. Some of them need it and some of them don't. 
    RGMII MAC doesn't need COL. 

    Can you please check with the MAC team on the necessity of COL?

    --
    Regards,
    Gokul.