• State Resolved
  • Locked Locked
  • Replies 1 reply
  • Subscribers 32 subscribers
  • Views 478 views
  • Users 0 members are here
Support feedback
Options
Options
Similar topics

This thread has been locked.

If you have a related question, please click the "Ask a related question" button in the top right corner. The newly created question will be automatically linked to this question.

DS250DF810: Using 25G retimer with 1G Ethernet

Vitaly And
Prodigy 180 points
Part Number: DS250DF810
Other Parts Discussed in Thread: DS280DF810

Hello,

according to the datasheet table 5 the device supports 1.25 Gpbs rate.

We connect them to SFP cage, our MAC is also multi-rate with 1G/10G/25G.

In 1G mode our MAC is in SGMII mode, it seems to be OK to connect to the retimer.

But what should be done in software? I haven't  found any explicit guide for this case...

Thank you.

  • +1
    TI__Mastermind 19135 points

    Hi,

    The TI DS250DF810 retimer supports 25.78125G and 10.3125Gbps in retimed mode. For 1.25Gbps operation the retimer channel needs to be set to CDR bypass mode. My recommendation would be to set the retimer to the mode where it automatically switches to CDR bypass mode whenever the CDR is unlocked. Then, you may set the retimer to either 10G or 25G Ethernet rates via channel register 0x2F. See details below from the retimer programming guide. This doc can be requested via the TI.com DS250DF810 product page

    Standard Data Rate Settings

    The DS2x0DFx10 channels must each be preprogrammed for the expected data rate(s) to ensure CDR lock. Users can program the rate/sub-rate to one of a set of pre-defined standard values to quickly configure the DS2x0DFx10. The rate/sub-rate settings are programmed by writing to channel Reg_0x2F[7:4].

    Table. Standard Rate Modes Configurable from Reg_0x2F

    STANDARD RATE SETTING

    REG_0x2F VALUE [HEX]

    REG_0x2F WRITE MASK [HEX]

    10.3125 Gbps

    00

    F0

    10.9375 Gbps

    10

    12.5 Gbps

    20

    RESERVED

    30

    25.0 Gbps

    40

    25.78125 Gbps (default)

    50

    RESERVED

    60

    28.125 Gbps

    70 (DS280DF810 only)

      

    Select Output Mode when CDR is Not Locked

    By default, the DS2x0DFx10 output is muted when the CDR is not locked. The DS2x0DFx10 can optionally be configured to output raw, un-retimed data when the CDR is not in lock.

    Table. Select output mode when CDR is not locked

    STEP

    SHARED/ CHANNEL REGISTER SET

    OPERATION

    REGISTER ADDRESS [HEX]

    REGISTER VALUE [HEX]

    WRITE MASK [HEX]

    COMMENT

    1

    Channel

    Write

    1E

    E0

    E0

    PFD_SEL_DATA_PRELCK=3' b111: Mute (default)

    Note: Reg_0x09[5] must be 0, which is the default.

    00

    E0

    PFD_SEL_DATA_PRELCK=3' b000: Raw, un-retimed data Note: Reg_0x09[5] must be 0, which is the default.

    Regards,

    Rodrigo