DP83869HM: Configuring DP83869HM without controller

Hi,

Thanks for the information. If we use these strapping options can we still achieve the required functionality(SGMII to 1000Base-T) without MDC/MDIO control. Are there any other things to be taken care while eliminating MDC/MDIO interface

Hi Sneha, 

The PHY will work if the strappings are properly done, and the PHY is being used within our recommendation per datasheet.
Note that for LED strapping there is a special configuration of strapping to be done to ensure that the PHY straps to the desired configuration and the LED properly works. Below is the reference:
 

In addition, we recommend to have MDC and MDIO line available as a test point in case there are unexpected modes of failure of the PHY and we may need to access MDIO in order to get register dump and such. 

Please let me know if you have any other questions. 

Best,

J

Hi J,

1. In our design, we have three DP83869HM devices sharing the same MDC/MDIO interface. I believe each DP83869HM has to be configured with a different PHY address.
Below is the attached PHY strapping circuit for configuring three different addresses. Please confirm on the correctness of the below strapping.

2. What should be the strapping method and resistor values for the below pins on the PHY to support SGMII(or 1000Base-KX) to 1000Base-T conversion, LEDs to indicated 1000Mbps link and activity.

1. RX_D2(pin 35)

2. RX_D3(pin 36)

3. LED_0(pin 47)

4. LED_1(pin 46)

5. LED_2(pin 45)

3. If RGMII and JTAG interfaces are not used, can these pins be left floated?

Thanks & Regards,

Sneha

Hi Sneha, 

Sneha R said:

1. In our design, we have three DP83869HM devices sharing the same MDC/MDIO interface. I believe each DP83869HM has to be configured with a different PHY address.
Below is the attached PHY strapping circuit for configuring three different addresses. Please confirm on the correctness of the below strapping.

Your setup is correct. 

Sneha R said:

2. What should be the strapping method and resistor values for the below pins on the PHY to support SGMII(or 1000Base-KX) to 1000Base-T conversion, LEDs to indicated 1000Mbps link and activity.

For SGMII to copper, 
The following pins are needed and will be in two level strapping so mode 1 corresponds to this: 

1. RX_D2(pin 35) - mode 1

2. RX_D3(pin 36) - mode 1

    JTAG_TDO/GPIO_1 - mode 0

For fiber to copper media conversion, the following pins are needed in strapping options as such:

1. RX_D2(pin 35) - mode 1

2. RX_D3(pin 36) - mode 0

    JTAG_TDO/GPIO_1 - mode 1

For 1000Mbps link and activity, sgmii to copper defaults LED to the highlighted:

Please note that LED strapping configurations are for auto-negotiation, not LED settings itself. To modify from the default LED setting, you will need register access. 

Sneha R said:

3. If RGMII and JTAG interfaces are not used, can these pins be left floated?

Yes, they will be in JTAG signals will be in Hi-Z/pull-up state and RGMII signals will be in pulldown states. So, they can be left floating. 

Best,
J