• State Resolved
  • Locked Locked
  • Replies 11 replies
  • Answers 6 answers
  • Subscribers 35 subscribers
  • Views 1454 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.

DS125DF111: Register set up for locking to 6.25 Gbps input

user4779049
Expert 2345 points
Part Number: DS125DF111
Other Parts Discussed in Thread: DS125DF410, DS125DF410EVM, DS110DF410

Hi Team,

Please advise me no how to make DS125DF111/410 lock to 6.25 Gbps input.

I tried to make DS125DF111 lock to a 6.25Gbps input and made it lock to the input data using
High level page of the Sigcon Architect.

Then I analyzed the register access of the high level page and tried to duplicate the scrip as bellow
Using low level page of the Sigcon Architect.
Because I need to implement the register access using a Micro-controller on a system board.
However, I could not make DS125DF111 lock to the 6.25Gbps input.
Please let me know proper register setting procedure.

WRITE I2C 0x30 Address 0x2F 0xA6      // Rate & Sub rate = 10b & 10b

WRITE I2C 0x30 Address 0x60 0x80      // PPM 0x3E80 & Ovr bit = 1b
WRITE I2C 0x30 Address 0x61 0xBE

WRITE I2C 0x30 Address 0x62 0x80      // PPM 0x3E80 & Ovr bit = 1b
WRITE I2C 0x30 Address 0x63 0xBE

WRITE I2C 0x30 Address 0x64 0xFF
WRITE I2C 0x30 Address 0x65 0x00

WRITE I2C 0x30 Address 0x0A 0x1C      //Reset CDR
WRITE I2C 0x30 Address 0x0A 0x10      //Release CDR reset

Mita

  • 0
    TI__Guru* 93670 points
    Hi Mita-San,

    I checked your register settings and it seems correct.

    Please use the register settings you have but use 6.14Gbps. Does it lock at this data rate? I am working on finding one DS125DF111 board so I can check this as well.

    Regards,,,nasser
  • 0 in reply to Nasser Mohammadi
    Expert 2345 points

    Nasser-san,

    Thank you for your feedback.
    Please test the register settings using EVM.

    The 6.25 Gbps (POP3) is in the standard data rate.
    I supposed that only Address 0x2F was needed to lock to 6.25 Gbps input
    for the standard data rate.

    WRITE I2C 0x30 Address 0x2F 0xA6      // Rate & Sub rate = 10b & 10b


    However, I analyzed the script log on High level page, and found that the address 0x60
    through address 0x65 were accessed.

    Mita

  • 0 in reply to user4779049
    TI__Mastermind 43795 points

    Mita,

    The DS125DF111 will need to program registers 0x60-0x63 to lock to rates other than 9.8304, 4.9152, 2.4576, 1.2288 Gbps

    In order to lock to the 6.25 Gbps rate in addition to the datarates listed above, program

    0x60 = 26'h

    0x61 = B1'h

    0x62 = 80'h

    0x63 = BE'h

    0x64 = FF'h

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Expert 2345 points

    Lee-san,

    Thank you. I got it.

    Mita

  • 0 in reply to user4779049
    Guru 19785 points
    Hi Lee-san,

    Please allow me to ask questions in specific.

    1). Register setting REG 0x60 = 26'h and REG 0x61 = B1'h is not required, since this is not the PPM setting for 12.5Gbps VCO setting, am I correct ?
    I think we should use the same setting as following.

    REG 0x60 = 0x80
    REG 0x61 = 0xBE
    REG 0x62 = 0x80
    REG 0x63 = 0xBE
    REG 0x64 = 0xFF

    2). What was the reason that Standard-based Mode PROP3 (6.25Gbps) setting didn't work ?

    Thanks for your support.

    Best Regards,
    Kawai
  • 0 in reply to Kawai
    TI__Mastermind 43795 points

    Kawai-san,

    The SMBus register programming for rate/subrate will only alter the VCO divide ratios.  The values in registers 0x60-0x61 control the Group0 VCO and 0x62-0x63 control the Group1 VCO.  If you only require 6.25 and 12.5 Gbps then you can program both Group0 and Group1 registers to the same values of 0x80 and 0xBE.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Guru 19785 points

    Hi Lee-san,

    Thanks for the answer. Is this because the device is DS125DF111, which doesn't have Standards-Based Mode register setting like DF410 ?

    My understanding for DF410 is that when you program REG 0x2F, PPM settings will be automatically updated in back ground for each data rate .

    Best Regards,

    Kawai

  • 0 in reply to Kawai
    TI__Mastermind 43795 points

    Hi Kawai-san,

    The DS125DF111 uses the Rate/Subrate selection to select the device VCO divide ratios only.

    For a complete description see datasheet section 7.5.1.11 on page 22

    www.ti.com/.../ds125df111.pdf

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Guru 19785 points

    Hi Lee-san,

    First, we were thinking that DF410 and DF111 has the same function.

    Actually, customer is using DS125DF410 and since we don't have DS125DF410EVM, we are using DS125DF111.

    Q1). My understanding is that DS125DF410 has standards based mode which will program REG 0x6X PPM information. However, DF111 does not have this mode and it always requires REG 0x6X PPM registers to be programmed. Am I correct ?

    Q2). It is strange that DS125DF410 requires REG 0x6X PPM registers to be set to acquire stable CDR lock. In DF410 it has PROP3 setting which can lock to 6.25Gbps. However, customer couldn't achieve lock if only REG 0x2F is programmed. Is this correct operation ?

    Below is the table in DS125DF410 Data Sheet.

    Best Regards,

    Kawai

  • 0 in reply to Kawai
    TI__Mastermind 43795 points

    Hi Kawai,

    The DS125DF111 was designed starting with the DS125DF410 device.  They are just about identical, but with some digital control differences.


    Q1. The DS1x0DF111 always requires the registers 0x60-0x64 to be programmed to lock to non-default values.

    Q2. I believe this is correct.  The following paragraph from the DF410 datasheet indicates 0x60 - 0x64 will always need to be programmed.

    As is the case with the standards-based mode of operation, the expected PPM count value and the PPM count tolerance must be written to registers 0x60, 0x61, 0x62, 0x63, and 0x64. These are computed exactly as described above for the standards-based mode of operation. Since the frequency-range-based mode of operation uses both Group 0 and Group 1 with the same expected PPM count, the same values should be loaded into the pairs of registers 0x60 and 0x62, and 0x61 and 0x63.

    Regards,

    Lee

  • 0 in reply to Lee Sledjeski
    Guru 19785 points
    Hi Lee-san,

    Thanks for your comments.
    I will post as another question since this is relating to DS110DF410.

    Best Regards,
    Kawai