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TLK106 Cable Diagnostic functions

O_Vladimir
Prodigy 20 points
Other Parts Discussed in Thread: TLK106, TLK110, TLK105

Good day!
I have a chip of tlk106 and I wanted to use Cable Diagnostic functions of this chip.

However during its study I had some questions.

1) The description of the TDR and ALCD functions in datashet short and incomplete. Whether there is documentation with more detailed descriptions somewhere?

2) In registers bit fields and their assignments are described. But I didn't find a method how to transform values from fields and registers to real physical parameters of the line. For example:
a) Cable Diagnostic Specific Control Register 2 (CDSCR2), TDR pulse control accepts value from 0x0 to 0xF. And how many it in nanoseconds?
b) Cable Diagnostic Specific Control Register 3 (CDSCR3), Cable length cfg accepts value from 0x00 to 0xFF. And how many it in meters?
c) How to translate the values received from the registers Cable Diagnostic Location Results Register in meters? How to transfer values from the registers Cable Diagnostic Amplitude Results Register to volts? Whether there are for this purpose some formulas and where it is possible to look at them?

Vladimir.

  • 0
    TI__Mastermind 23675 points

    Hi Vladimir,

    I am discussing this question with my colleagues and will get back to you.

    Kind regards,

    Ross

  • 0 in reply to Ross Pimentel
    TI__Mastermind 23675 points
    Hi Vladimir,

    The TDR function is what you appear to be interested in from the above description, correct?

    We do not have an app note yet on this function, but I will describe it here so that you can use it until we have a formal document.

    TDR Function:
    1. Ensure that register 0x0171 bit[3:0] are set to C(h)
    2. Ensure that register 0x0173 bit[15:8] are set to FF(h)
    3. Ensure that register 0x0177 bit[15:8] are set to 18(h)

    To run TDR you will need to write to register 0x001E to enable to pulse.
    1. Write 0x8000 to register 0x001E
    2. Read register 0x001E, bit[2] should be '1' when the task is complete

    To view results:
    1. Read register 0x0180, 0x0181, 0x0182, 0x0183, 0x0184
    2. If there is a reflection within 0-3m, register 0x0180 bits[3:0] will read 0C(h). This is ok since there is self reflection and we can account for it in the formula.
    3. You will notice that in register 0x0180 it indicates peaks 1 and 2, register 0x0181 indicates peaks 3 and 4, register 0x0182 indicates peaks 1 and 5, register 0x0183 indicates peaks 2 and 3, register 0x0184 indicates peaks 4 and 5. The extra registers are for redundancy.

    After reading the values from registers 0x0180 - 0x0182, you can convert to actual cable length value by performing the following:
    1. Convert bits[15:8] and bits[7:0] into decimal values
    2. If you read 00 as the value for some of the peaks it is ok since it just means that there are no faults to reflect off of.
    4. Perform the following to find the length on the cable of each peak:
    IL(intermediate peak encountered) = (decimal_value_of_peak * 0.8621) - 8
    FL(actual peak location) = IL + ((70 - IL) * 0.01)

    Example:
    Read register 0x0180 to be = 0x0029
    Read register 0x0181 - 0x0182 = 0x0000

    FL = 41*0.8621 - 8 = 27.35m cable (register 0x0180 did not read 0C so might not need to account for self reflection)

    Example 2:
    Read register 0x0180 to be = 0x880C
    Read register 0x0181 to be = 0x0000
    Read register 0x0182 to be = 0x0C00
    Read register 0x0183 to be = 0x0088

    IL = 136*0.8621 - 8 = 117.25m cable
    FL = 117.25 + (70 - 117.25)*0.01 = 116.77m cable


    Kind regards,
    Ross
  • 0 in reply to Ross Pimentel
    Prodigy 20 points
    Good day!
    Thank you for the response. It just that information which I looked for.

    But I want to add. There is Application note for TLK110 chip. (e2e.ti.com/.../5280.2011_2D00_07_2D00_13_5F00_TDR_5F00_ALCD_5F00_AppNote_5F00_Rev_5F00_0_5F00_2.pdf)
    But it is possible to find it only through Google, on this site it isn't mentioned anywhere. And also in this app note is no mentioning of TLK105/TLK106, though as I understand, the Cable Diagnostic functions in them identical.

    Kind regards,
    Vladimir.
  • 0 in reply to O_Vladimir
    TI__Mastermind 23675 points
    Hi Vladimir,

    You are correct that the cable diagnostic functions are the same for TLK110 and TLK105/6. Thank you for finding this app note. It must have gotten lost when we updated the site. I really appreciate you finding this since it might mean there are other app notes not showing up on our site.

    Kind regards,
    Ross