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DP83869HM: Understanding DP 83869 HM 1000 BASE-T Operations

user6150189
Intellectual 460 points
Part Number: DP83869HM


I have a question about the STRAP PIN setting on the DP 83869 HM.
Referring to the data sheet "9.5 Programming", by attaching an external resistor to the STRAP PIN, it is set to [SGMII to Copper Mode] + [Auto-negotiation, 1000/100 advertised], but the speed of 1000 BASE is not available and it is limited to 100 BASE.
Are there any possible factors?
The IC's internal register settings remain at default values.
■STRAP PIN settings
・Functional Mode Strap: SGMII to Copper
・Copper Ethernet Strap: Auto-negotiation, 1000/100 advertised, Auto MDI-X
■Evaluation environment
PC - (Ehternet cable) - DP83869HM - SGMII (coaxial) - DP83869HM - (Ethernet cable) - PC
Incidentally, the Copper Ethernet Strap settings were different between the datasheet and the application report [SNLA 318], so we checked both settings, but both were limited to 100 BASE.
  • 0
    TI__Expert 7040 points

    Hello,

    Thanks for your question. Can you please provide the schematic of the strap settings on the three Function Mode strap pins, as well as three Copper Ethernet strap pins? Please also provide the register information for register 0x0000-0x001F. I am particularly interested if register 0x0009 shows 1000Base-X capabilities advertised.

    Regards,
    Justin 

  • 0 in reply to Justin Lazaruk
    Intellectual 460 points
    Hello.Answer below.
    ■three Function Mode strap: SGMII to Copper
    　JTAG _ TDO/GPI O _ 1 = 0 (Rhi = open, Rlo = 2.49 k)
    　RX _ D3 = 1 (Rhi = 2.49 k, Rlo = open)
    　RX _ D2 = 1 (Rhi = 2.49 k, Rlo = open)
    ■three Copper Ethernet Strap: Auto-negotiation, 1000/100
    patturn1 (Datasheet Reference)
    　LED _ 0 = 0 (Rhi = open, Rlo = 2.49 k)
    　LED _ 1 = 1 (Rhi = 2.49 k, Rlo = open)
    　LED _ 2 = 0 (Rhi = open, Rlo = 2.49 k)
    patturn2 (Application Report Reference)
    　LED _ 0 = 0 (Rhi = open, Rlo = 2.49 k)
    　LED _ 1 = 0 (Rhi = open, Rlo = 2.49 k)
    　LED _ 2 = 1 (Rhi = 2.49 k, Rlo = open)
    ※Both patturn1 and patturn2 are limited to 100 BASE.
    ■register 0x0000 - 0x001F
    　Default value (factory default value). I am not writing to the register.
  • 0 in reply to user6150189
    TI__Expert 7040 points

    Hello,

    Thank you for your response. I will look into the difference between the datasheet and the application note. 

    While you are not programming any registers, the strap configuration will load values into the registers based on the settings you have designed. Please include what the register values are for 0x00-0x1F to review if they match the expected strap settings.

    Regards,
    Justin