• State TI Thinks Resolved
  • Locked Locked
  • Replies 6 replies
  • Answers 3 answers
  • Subscribers 33 subscribers
  • Views 811 views
  • Users 0 members are here
Support feedback
Options
Options
Related

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.

DS125DF410: CoaXPress

ttd
Mastermind 8600 points
Part Number: DS125DF410
Other Parts Discussed in Thread: DS125DF1610

Dear Technical Support Team,

My application uses CoaXPress with DS125DF410.

The data rate is 6.25Gbps. Then if VCO frequency is the same such as 6.25Gbps and DIVIDER RATIONS sets "1", the CDR is not lock.

However VCO frequency is 12.5Gbps and DIVIDER RATION sets "2" such as PROP3 and interlaken1, then CDR is lock.

Do you know the reason why CDR doesn't lock when data rate and VCO frequency are the same? 

Best Regards,

ttd

  • 0
    Mastermind 8600 points

    Dear Technical Support Team,

    Here is my configuration steps. Is there any mistake for CDR LOCK?

    Datarate is 6.25Gbps. 

    I don't use power superimposition(data and power) with CoaXpress.

    Reg addr data
    0x36 0x31
    0x09 0x00
    0x15 0x10
    0x16 0x7a
    0x17 0x36
    0x18 0x40
    0x2d 0x83
    0x2e 0x00
    0x2f 0xa6
    0x30 0x00
    0x31 0x20
    0x4a 0x30
    0x60 0x40
    0x61 0x9f
    0x62 0x40
    0x63 0x9f
    0x64 0xｆｆ
    0x0a 0x1c
    0x0a 0x10

    Best Regards,

    ttd

  • 0 in reply to ttd
    Mastermind 8600 points

    Dear Technical Support Team,

    There is a problem that the lock is released at the time of a specific data pattern.

    Since 8B10B is used on the camera side, 0 or 1 continues up to 4 times.
    When two or more 0/1 fluctuations (0/1 does not alternate) continue
    Is there a possibility that the lock will be released without recognizing the data rate (6.25 Gbps, etc.)?
    In that case, is there a setting to change the time until the unlock is detected?

    Best Regards,

    ttd

  • 0
    TI__Mastermind 19235 points

    Hi,

    If 0x2F is set 0 0xA6, the retimer should be able to lock to 6.25Gbps input data without any other additional register configuration. You do not need to manually change divide by setting (via 0x18) or the CDR rate (via 0x60 thru 0x63) for this case.

    The DS125DF1610 is a 12.5G retimer, so its VCO full rate frequency is 12.5GHz. Thus, 6.25Gbps entails setting divider ratio to 2.

    Cordially,

    Rodrigo Natal

    HSSC Applications Engineer

  • 0 in reply to ttd
    TI__Mastermind 19235 points

    Related to your 8B10B test pattern question, I do not quite understand what you are asking. From what I gather your transmitted data appears to include a 4T pattern run (i.e. four consecutive bits) while data rate is 6.25Gbps. It is possible this log run could be triggering the retimer Single Bit Transition(SBT) check to knock the channel out of lock. I would recommend to try running your test case while setting retimer channel register 0x0C bit 3 to 0, to disable the SBT check. 

    Cordially,

    Rodrigo Natal

  • 0 in reply to Rodrigo Natal
    Mastermind 8600 points

    Hi Rodrigo Natal,

    Thank you for your reply.

    If you disable SBT checking
    At rates that link (CDR lock), it now works even when retimer receives the data pattern that was previously unlocked.

    However, the current link (lock) rate is 1.25 / 2.5 / 5Gbps.
    For 3.125 / 6.25Gbps, it does not link (lock) at all.

    We have set 0x60 to 0x63, 0x18, 0x09 = 0x04.
    After that, setting 0x09 = 0x00 and changing 0x18 to 0x00 does not change the situation.

    ・When using 0x64, does bit7-6 of 0x67 need to be set to 1?
    0x18, 0x2F, 0x60-64, is there an order to set?

    ・There was a description that 6.25Gbps is unnecessary if 0x2F is set, but is this only for 6.25Gbps?

    ・Do other rates (1.25 / 2.5 / 3.125 / 5Gbps) need to be set to 0x18 / 0x60-64?

    ■additional information

    This is a test pattern that unlocks the CDR,
    It depends on the brightness data of the image, for example, unlocking occurs in the case where 0x35 continues.
    The sequence of data after 8B10B is 110001 1001.
    According to the CoaXPress standard, IDLE (including K28.5) is sent once to 100Word (400Byte).
    Even if 0x35 continues, it will be 400 at Max.
    I have tried the brightness values from 0 to 255, but the same is true for 5 to 6 data including 0x35 above.
    The unlock issue is occurring.

  • 0 in reply to ttd
    TI__Mastermind 19235 points

    Hi,

    1.25G/2.5G/5G is a separate VCO group from 3.125G/6.25G/12.5G. Thus, these settings require different CDR rate settings.

    • For 1.25G/2.5G/5G, you may set 0x2F = 0x26
    • For 6.25G you may set 0x2F = 0xB6

    　

    STANDARDS

    DATA RATES (Gb/s)

    VCO FREQUENCIES (GHz)

    DIVIDER RATIOS

    REGISTER 0x2F VALUE (hex)

    InfiniBand

    2.5, 5, 10

    10.0

    1, 2, 4

    0x26

    CPRI1

    2.4576, 4.9152, 9.8304

    9.8304

    1, 2, 4

    0x36

    CPRI2

    3.072, 6.144

    12.288

    2, 4

    0x46

    PROP3

    6.25

    12.5

    2

    0xA6

    Interlaken1

    3.125, 6.25

    12.5

    2, 4

    0xB6

    Interlaken2

    10.3125

    10.3125

    1

    0xC6

    Ethernet

    1.25, 10.3125

    10.0, 10.3125

    1, 8

    0xF6

    Cordially,

    Rodrigo Natal