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TLK105L: Precision Timing Configuration

Part Number: TLK105L

Hi,

The datasheet P.41 says as follows,
"Exact timing IEEE 1588 indication pulse can be adjusted using register 0x3f.
 Each increment of phase value is an 8-ns step."
in 5.2.6 IEEE 1588 Precision Timing Protocol Support.

I have a question about that register.

Register 0x003F, IEEE1588 Precision Timing Configuration (PTPCFG),
bits 15:13, PTP Transmit Timing & bits 12:10, PTP Receive Timing:

Are the timings from "Message Timestamp Point" in Figure 5-10.IEEE 1588 Message Timestamp Point?

(+0-ns to +56-ns)

Thank you in advance.

Best regards,
Takishin

  • Hello Takishin,

    The Message Timestamp Point mentioned in the datasheet is for reference. The pulse is generated after the SFD is received. So the 0ns to 56ns delay is measured from the actual reception of SFD and the generation of the indication pulse. When the timing is kept to 0ns then SFD pulse is generated as soon as SFD is received . If time delay is added then the SFD indication pulse is delayed after reception of SFD.

    -Regards,
    Aniruddha
  • In reply to Aniruddha Khadye:

    Hi Aniruddha-san,

    Thank you for your answer.

    I have another question.

    When the pulse is generated after the SFD is received, what does the following mean?

    "The pulse indicates the actual time the symbol is presented on the lines (for TX),
    or 'the first bit' where the /J/ symbol is received (RX)."
    (in 5.2.6 IEEE 1588 Precision Timing Protocol Support)

    Best regards,
    Takishin
  • In reply to takishin:

    Hello Takishin,

    The 'symbol' refers to /J/ symbol which is used in Ethernet frame as a start of stream. In transmit it represent the actual time for which the symbol was present on the line and in transmit it indicates when the /J/ symbol was received.

    -Regards,
    Aniruddha
  • In reply to Aniruddha Khadye:

    Hi Aniruddha-san,

    Thank you for your answer.
    I understand.

    Best regards,
    Takishin