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PTP implementation in STM32F437ZGT6

Question asked by JoseA on Sep 17, 2014
Latest reply on Sep 30, 2014 by JoseA
Hello. I am working in a R&D Project with the STM32 MCU. I have implemented Ethernet functionality like examples provided by ST. Frame transmission and reception are OK (checked with Wireshark).
Now I must add PTP synchronization. Code made by ST is created for the STM32F1 family (with the PTPv2 library) , so I have followed the documentation to migrate it to my specific MCU (STM32F4).
All operations seem to run without errors. The PTP stack receives the messages and interprets these, but I get continuously the message "updateOffset: cannot filter seconds" and the offset from master is always very far from the objective.
Also I have read the Reference Manual of the STM32, and I found an enhanced receive descriptor when the IEEE1588 (PTP) time stamp is enabled (see page 1168 of DocID018909 Rev 7). According to the Figure 383 (see attached image), RDES6 and RDES7 should hold the time stamp, but when I am debugging I can not found the time stamp values. Which internal register(s) does the enhanced descriptor get the time stamp from?

enhanced_RXdescriptor.png

Thank you very much!

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