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DP83TC812S-Q1: How can I determine whether this chip support PTP?

Hanlin Deng
Prodigy 40 points
Part Number: DP83TC812S-Q1
Other Parts Discussed in Thread: DP83TC817S-Q1, DP83TG721S-Q1, DP83TG720S-Q1

Tool/software:

By exploring the contents on webpages and datasheets, I have a simple PTP related summary about the following 4 Ethernet PHY chips.

DP83TC812S-Q1: IEEE 1588 SFD support (from datasheet) / None (from webpage)

DP83TC817S-Q1: IEEE 802.1AS time synchronization (from datasheet) / IEEE 1588v2/802.1AS Time Synchronization (from webpage)


DP83TG721S-Q1: IEEE 1588v2/802.1AS Time Synchronization (from datasheet) / IEEE 1588v2/802.1AS Time Synchronization (from webpage)

DP83TG720S-Q1: None (from datasheet) / None (from webpage)

I have the following 2 questions.

Q1. Knowing SFD is short for Start-of-frame Detect, can I argue that DP83TC812S-Q1 support PTP since SFD is designed as an improved method of software time stamping?

Q2. DP83TG720S-Q1 doesn't support either IEEE 1588v2/802.1AS Time Synchronization or IEEE 1588 SFD support, right?

  • 0
    TI__Mastermind 36263 points

    Hi Hanlin,

    1. Yes, this is correct.
    2. Yes, this is also correct.

    In general, there are several different ways to accomplish TSN, with varying degrees of accuracy.  I've listed these in order from least specialized hardware to most specialized hardware.

    1. Software based timestamping: Millisecond accuracy
    2. Timestamping in SOC (can be used in combination with SFD): Microsecond to nanosecond accuracy
    3. Time stamping in PHY: Nanosecond accuracy

    This white paper has more details on TSN you might find useful.

    https://www.ti.com/lit/wp/snla465/snla465.pdf

    Thanks,

    Drew