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DS125DF111: Consult DS125DF111

Part Number: DS125DF111

Dear Team,

We have to enable SFP10G & SFP1G connection for our product.

Here are all the configs we applied, the SFP 10G link up with a good eye diagram. However, the SFP 1G link up failed.

Could you provide any comments?

 

i2cset -y 0 0x19 0xff 0xC;
i2cset -y 0 0x19 0x0 0x4
i2cset -y 0 0x19 0x9 0x24
i2cset -y 0 0x19 0x18 0x0
i2cset -y 0 0x19 0x1e 0x21
i2cset -y 0 0x19 0x60 0x0
i2cset -y 0 0x19 0x61 0xb2
i2cset -y 0 0x19 0x62 0x90
i2cset -y 0 0x19 0x63 0xb3
i2cset -y 0 0x19 0x64 0xcd
i2cset -y 0 0x19 0x2d 0x82
i2cset -y 0 0x19 0x15 0x13
i2cset -y 0 0x19 0xa 0x1c
sleep 1
i2cset -y 0 0x19 0xa 0x10

Enable Raw data could get both 1G and 10G link up. Clear bit[5] of 0x9 and clear bit[7:5] of 0x1e.

Why does the link fail with retimed data? Please help to clarify this case.

 

i2cset -y 0 0x19 0xff 0xC;
i2cset -y 0 0x19 0x0 0x4
i2cset -y 0 0x19 0x9 0x1
i2cset -y 0 0x19 0x18 0x0
i2cset -y 0 0x19 0x1e 0x1
i2cset -y 0 0x19 0x60 0x0
i2cset -y 0 0x19 0x61 0xb2
i2cset -y 0 0x19 0x62 0x90
i2cset -y 0 0x19 0x63 0xb3
i2cset -y 0 0x19 0x64 0xcd
i2cset -y 0 0x19 0x2d 0x82
i2cset -y 0 0x19 0x15 0x13
i2cset -y 0 0x19 0xa 0x1c
sleep 1
i2cset -y 0 0x19 0xa 0x10

Many Thanks,

Jimmy

  • Hi Jimmy,

    Just taking a couple notes on these commands to better keep track of them.

    Register Address Register Write Data Description
    0xFF 0x0C Select channel registers
    0x00 0x04 Reset channel registers
    0x09 0x24 Enable override output mux; enable override divider select
    0x18 0x00 Selects full rate divider ratio
    0x1E 0x21 Select retimed data output
    0x60 0x00 Set VCO for 10 Gbps, 10.3125 Gbps according to table 12 in datasheet.
    0x61 0xB2 Set VCO for 10 Gbps, 10.3125 Gbps according to table 12 in datasheet.
    0x62 0x90 Set VCO for 10 Gbps, 10.3125 Gbps according to table 12 in datasheet.
    0x63 0xB3 Set VCO for 10 Gbps, 10.3125 Gbps according to table 12 in datasheet.
    0x64 0xCD Set VCO for 10 Gbps, 10.3125 Gbps according to table 12 in datasheet.
    0x2D 0x82 Set VOD to 800 mV
    0x15 0x13 Set de-emphasis to -5 dB
    0x0A 0x1C Assert CDR reset
    - - Wait 1 second
    0x0A 0x10 Release CDR reset

    Looking over this configuration, I think there are two issues.

    1) Manually overriding divider select

    • I believe this is the primary issue causing the inability for 1G link up.  Forcing a divide ratio of 1 means that the acceptable data rates for this configuration are 10 Gbps and 10.3125 Gbps.  For 1.25 Gbps, you need 10 Gbps / 8.

    2) Overriding output mux

    • It  is best to leave output mux to mute so that it will not output data without CDR lock.  For more details on this, see section 7.5.1.13 in the datasheet.

    Recommended configuration:

    Remove writes to 0x09, 0x18, 0x1E.  Set divide ratio via 0x2F.

    Register Address Register Write Data Description
    0xFF 0x0C Select channel registers
    0x00 0x04 Reset channel registers
    0x2F 0x06 Select divide ratios of 8 and 1 (see Table 9 in datasheet)
    0x60 0x00 Set VCO for 10 Gbps, 10.3125 Gbps according to table 12 in datasheet.
    0x61 0xB2 Set VCO for 10 Gbps, 10.3125 Gbps according to table 12 in datasheet.
    0x62 0x90 Set VCO for 10 Gbps, 10.3125 Gbps according to table 12 in datasheet.
    0x63 0xB3 Set VCO for 10 Gbps, 10.3125 Gbps according to table 12 in datasheet.
    0x64 0xCD Set VCO for 10 Gbps, 10.3125 Gbps according to table 12 in datasheet.
    0x2D 0x82 Set VOD to 800 mV
    0x15 0x13 Set de-emphasis to -5 dB
    0x0A 0x1C Assert CDR reset
    - - Wait 1 second
    0x0A 0x10 Release CDR reset

    Please let me know if this resolves the issue.

    Thanks,

    Drew