Kinetis MicrocontrollersのトピックRe: Kinetis K64 IEEE1588 transmit timestamping

Kinetis K64 IEEE1588 transmit timestamping

ombra32 — Tue, 27 Aug 2019 12:30:28 GMT

Hi,

reference manual K64P144M120SF5RM at chapter "45.5.10.3 Receive timestamping" reports that for received frames the Ethernet MAC latches the timer value in correspondence of SFD field.

What happens for transmit frames? When is the timer latched?

This behavior is not explained at relative chapter "45.5.10.2 Transmit timestamping".

Regards,

Marco

Re: Kinetis K64 IEEE1588 transmit timestamping

FelipeGarcia — Wed, 28 Aug 2019 15:52:08 GMT

Hello Marco,

Unfortunately, this specific timing is not stated in documentation. However, as the Reference Manual indicates, the MAC records the timestamp for the frame in ENETn_ATSTMP. ENETn_EIR[TS_AVAIL] is set to indicate that a new timestamp is available.

Basically, what it means is that you will have to wait till ENETn_EIR[TS_AVAIL] is set to read the Timestamp of Last Transmitted Frame (ATSTMP).

For more information I also suggest you to check the following application note regarding IEEE1588 and Kinetis for reference.

https://www.nxp.com/docs/en/application-note/AN4332.pdf

Best regards,

Felipe

Re: Kinetis K64 IEEE1588 transmit timestamping

ombra32 — Thu, 29 Aug 2019 07:46:46 GMT

I know how PTP works, and I looked up FRDM-K64F 1588 bare metal example provided in SDK 2.6.0.

PTP synchronization mechanism between 2 nodes works well.

But in my project I need to evaluate the accurate propagation delay between 2 nodes, connected via Ethernet cable in a point-to-point configuration.

To do so, I need to know the exact position of timer latching for both transmit and receive packets, in relation to the Ethernet packet or related to TXEN/CRS_DV MAC signals.

Regards,

Marco

Re: Kinetis K64 IEEE1588 transmit timestamping

ombra32 — Thu, 05 Sep 2019 13:07:49 GMT

Is there a way to know the exact position of timer latching for both transmit and receive packets, in relation to the Ethernet packet or related to TXEN/CRS_DV MAC signals?

Re: Kinetis K64 IEEE1588 transmit timestamping

ombra32 — Wed, 18 Sep 2019 10:12:01 GMT

Can anybody help?

Re: Kinetis K64 IEEE1588 transmit timestamping

FelipeGarcia — Wed, 18 Sep 2019 19:17:30 GMT

Hello Marco,

Please accept my apologies for my late reply. I will try to ask this internally to see if we can get any feedback.

Sorry for the inconveniences.

Best regards,

Felipe

Re: Kinetis K64 IEEE1588 transmit timestamping

ombra32 — Mon, 07 Oct 2019 06:44:13 GMT

Hi Felipe,

any news?

Regards,

Marco

Re: Kinetis K64 IEEE1588 transmit timestamping

FelipeGarcia — Tue, 08 Oct 2019 19:58:06 GMT

Hi Marco,

I have escalated this question with our internal team. I will let you know whenever I received a response. Thanks for your patience.

Best regards,

Felipe

Re: Kinetis K64 IEEE1588 transmit timestamping

FelipeGarcia — Mon, 14 Oct 2019 20:30:26 GMT

Hi Marco,

Sorry but this is the only information I could collect from internal.

When user writes the TS bit in Enhanced transmit buffer descriptor field, the Ethernet MAC will timestamp the frame that is ready to transmit and valid when EIR[TS_AVAIL] is set.

Regards,

Felipe