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AM5718: AM5718 utilizing IEEE 1588 SFD pulse from DP83822

Kris Ganev
Intellectual 355 points
Part Number: AM5718
Other Parts Discussed in Thread: DP83822I, , AM3358

Hello,

We are planning to use DP83822I, which supports IEEE 1588 indication pulse at the SFD (start frame delimiter). It can generate receive and transmit SFD.

Is there a specific I/O pins on the AM5718 that need to be used for the receive and transmit SFD pulses from DP83822I?

Also is there a specific I/O pins on the AM3358 that need to be used for the receive and transmit SFD pulses from DP83822I?

  • 0
    TI__Mastermind 37435 points

    Hi,

    No there is no specific IO pin (on either AM57 or AM3) for this pulse, there are pins within ICSS and CPSW which can timestamp an input signal (see latch0_in and CPTS module) but there is nothing specific for this. I am assuming that you want to implement PTP, Are you planning to use this with GMAC or ICSS ? As per the description, the output can be routed to either LED_0,LED_1(GPIO1),COL(GPIO2),RX_D3(GPIO3),INT/PWDN_Nand CRS pins.

    If you are not using Half Duplex then you should be able to route them to COL/CRS and then connect those to any other pin on the SoC.

    I did find some documentation on this online here and here, in case you haven't seen them already.

    Regards

    Vineet

  • 0 in reply to Vineet Roy
    Intellectual 355 points

    Hi Vineet,

    We are going to use GMAC in 10/100 Full Duplex mode and would like to implement IEEE 1588 PTP. We also prefer the MII interface because of lower EMI (25 MHz clock) and lower latency but RGMII may be acceptable as well. Does it matter for the PTP implementation - MII or RGMII?

    I also found in the AM5718 TRM (rev I) on page 6496 and AM3358 TRM (rev Q) page 2068 that specific timer inputs have to be used to time stamp Ethernet event. Look at the CPTS_EVENT_HIGH register values (AM5718 TRM rev I, page 6637) Ehternet_Receive_Event and Ethernet_Transmit_Event which looks like would be the DP83822I receive and transmt SFDs.

    It appear that these timer inputs would be the correct pins for this purpose.

    If we end up using MII interface, I am planing to use DP83822I LED_0 and the INT/PWDN_N pins for the receive and trasmit SFDs. Do you see any issues with that?

    The latch_in0 signal appears to be a part of the ICSS IEP module.

    Thanks,

    Kris

  • 0 in reply to Kris Ganev
    TI__Mastermind 37435 points

    Hi Kris,

    Sorry for the delay

    Kris Ganev said:
    Does it matter for the PTP implementation - MII or RGMII?

    No, it should not matter

    Kris Ganev said:
    If we end up using MII interface, I am planing to use DP83822I LED_0 and the INT/PWDN_N pins for the receive and trasmit SFDs. Do you see any issues with that?

    I don't see any issues as such but I would get the HW schematics reviewed once for sanity to avoid any issues. Please reach out to your TI representative.

    Kris Ganev said:
    The latch_in0 signal appears to be a part of the ICSS IEP module.

    Yes, it wasn't apparent from your first post which module you were going to use.

    Based on your replies I was just wondering if you are planning to use some existing PTP implementation or build something custom. PTP on GMAC is already supported, you can see this link for more details.

    Regards

    Vineet