Best practice for time-deterministic (TAS) traffic when using LLCE + PFE CAN2ETH

[arsalimam]

Hello NXP Team,

We are working on a zonal architecture using S32G399A as Zone Controllers connected to HPC

Current Architecture:

• We are currently using the GMAC with full Time-Aware Shaper (TAS / 802.1Qbv) support along with complete TSN features.
• DDS runs over this GMAC path, and we have good time determinism for our service-oriented traffic.

New Exploration:

• We have successfully brought up and tested the official NXP LLCE + PFE sample application (CAN2ETH / ETH2CAN) as described in AN13423.
• The goal is to offload selected high-frequency / low-latency CAN signals from ECUs directly via LLCE → PFE (IEEE1722 AVTP over UDP) to reduce CPU load and latency on the Zone Controller.
• From community discussions, we understand that PFE only supports 802.1AS-Rev (time synchronization) and does not support Time-Aware Shaper (802.1Qbv / TAS) or Frame Preemption, unlike GMAC.

Question / Request for Guidance:

Since LLCE is tightly integrated with PFE (using PFE_HIF3), what is NXP’s recommended best practice in this scenario?

1. Can we enable TAS support on PFE by using / customizing the PFE source code provided by NXP? (I saw that NXP provides PFE source code – would this help us add or enable TAS functionality?)

2. If TAS cannot be enabled on PFE, what is NXP’s recommended best practice to achieve strong time determinism for the LLCE + PFE CAN2ETH traffic?

3. Should critical time-sensitive CAN signals continue to use the GMAC + TAS path, while only non-critical or high-volume signals use LLCE + PFE?
4. Is the recommended approach to rely on an external TSN switch (such as SJA1110) downstream of the PFE port to provide full TAS scheduling for the tunneled traffic?
5. Are there any plans or firmware updates that will add TAS support on PFE in the future?

We want to decide the right split between GMAC and PFE paths without compromising determinism for safety-relevant or hard real-time signals.

Any official guidance, reference designs, or configuration recommendations would be very helpful.

Thank you in advance!

Best regards,

Arsal Imam

SDV Architect @ GK Automobiltechnologie (Disrupt)

[arsalimam]

Hello Joey_z,

Thank you for your prompt response and for pointing me to the AUTOSAR_MCAL_ETH_43_PFE_UM.pdf. I appreciate the clarification, we will review the PFE MCAL driver documentation and explore Time-Aware Shaper (TAS / 802.1Qbv) configuration through the EB (Elektrobit) tool.

As a quick follow-up question: Does the PFE MCAL driver also support Frame Preemption (IEEE 802.1Qbu / 802.3br)? If yes, could you please share the relevant section in the User Manual or any configuration guidance for enabling it alongside TAS?

We are trying to fully understand the TSN feature set available on the PFE path before finalizing the traffic split between GMAC and LLCE+PFE. Thank you again for your support.

Best regards

[Joey_z]

Hi，arsalimam

As a quick follow-up question: Does the PFE MCAL driver also support Frame Preemption (IEEE 802.1Qbu / 802.3br)?

>>>PFE does not support it.

BR

Joey

[Joey_z · Accepted solution]

Hi,arsalimam

Refer to the AUTOSAR_MCAL_ETH_43_PFE_UM.pdf, PFE MCAL driver supports the Time Aware shaper, the shaper can be configured in the EB.

Joey_z_0-1782814096067.png

Joey_z_1-1782814378495.png

Hope this information can help you.

BR

Joey

[Joey_z]

Hi,arsalimam

Thank you for your contacting and detail information.

I have received your questions and will help you to check it.

BR

Joey