SPRUII0F May 2019 – June 2024 TMS320F28384D , TMS320F28384D-Q1 , TMS320F28384S , TMS320F28384S-Q1 , TMS320F28386D , TMS320F28386D-Q1 , TMS320F28386S , TMS320F28386S-Q1 , TMS320F28388D , TMS320F28388S
The MAC captures a timestamp when the Start Packet Delimiter (SFD) of a packet is sent on the MII interface. The packets, for which the timestamps has to be captured can be controlled on per-packet basis. Each Transmit packet can be marked to indicate whether a timestamp can be captured for each packet.
The MAC does not process the transmitted packets to identify the PTP packets. You need to specify the packets for which you want to capture timestamps.
You can specify the packets by using the control bits in the Transmit descriptor. The MAC returns the timestamp to the software inside the corresponding Transmit descriptor, thus connecting the timestamp automatically to the specific PTP packet. The 64-bit timestamp information is written to the TDES0 and TDES1 fields. The TDES0 field holds the 32 least-significant bits of the timestamp.