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MCU-PLUS-SDK-AM243X: LWIP CPSW Example - How to read Timestamp after DP83869 trigger?

Keito Katafuchi
Intellectual 255 points
Part Number: MCU-PLUS-SDK-AM243X
Other Parts Discussed in Thread: DP83869

I am pretty new to this level of embedded programming, so forgive me if this is a simple question.

I am using MCU-PLUS-SDK-AM243X v9.01.
I'm trying to get the PDK/.../examples/networking/lwip/enet_cpsw_tcpserver/client examples to work with IEEE 1588 timestamp from DP83869.
I want to send a packet (calling netconn_write()) and print the timestamp.

As I understand it, the DP83869 can be configured so on TX (SFD) it toggles a GPIO to the MAC.
The MAC then uses that GPIO toggle to get a timestamp, so we know exactly when the packet was passed out to the network.
Same thing when receiving some data.

I know the PDK/.../examples/networking/tsn/gptp_lwip_cpsw is built around that function/capability, but I am totally lost.

Where should I look for a function that triggers on GPIO from the DP83869 for the PTP trigger, so I can figure out how to access the timestamp?

EDIT

I spent more time looking through schematics / SDK documentation. I might have been mistaken...does the AM243x-LP even use the DP83869 GPIO pins to trigger the timestamp?
I can't see when/where the timestamp is recorded...?

  • 0
    Intellectual 255 points

    Nevermind. Looking at the schematics I see the DP83869 can not be used for the TimeStamp mechanism. Pins 22/45 of the PHY do not return to the SoC to be used for triggering timestamps.

    Instead, I see the CPTS module is used, where Ethernet packets (Tx/Rx) trigger TImeStamp capture events that go to the Event FIFO.
    I will create a separate thread for my questions regarding the CPTS module.