topic PTP clock source on RT106x in i.MX RT Crossover MCUs

PTP clock source on RT106x

glaukos — Fri, 19 Jul 2024 07:39:29 GMT

Hi there,

I am trying to implement PTP on a RT1064. Chapter 41 on the 10/100-Mbps Ethernet MAC (ENET) of the RT1064 Reference Manual suggests that the adjustable timer module can be clocked with various frequencies.

By default, the adjustable timer module is clocked by a 25MHz clock. This gives a resolution of 40ns. I would like to clock the adjustable timer module with a higher frequency, to achieve a greater resolution and therefore higher accuracy.

I suspect that currently the adjustable timer module is clocked from the ENET_25M_REF_CLK. Is it possible to change the source clock of the adjustable timer module? I have not found anything on it in the Reference Manual.

Thank you for your help.

Re: PTP clock source on RT106x

Omar_Anguiano — Tue, 23 Jul 2024 00:10:10 GMT

You can use config tools to change the frequency and source of ref clock.

Best regards,
Omar

Re: PTP clock source on RT106x

glaukos — Tue, 23 Jul 2024 07:00:56 GMT

Hello Omar,

thank you for your reply.

If I understand you correctly, you recommend changing ENET_REF_CLK to achieve a higher frequency adjustable timer module. However, my observation is that the adjustable timer module is clocked from ENET_25M_REF_CLK, not ENET_REF_CLK. Changing ENET_REF_CLK has therefore no effect on the adjustable timer module. ENET_25M_REF_CLK is fixed to 25MHz and cannot be changed.

If you know how to change the source of the adjustable timer module from ENET_25M_REF_CLK to ENET_REF_CLK or ENET_125M_CLK, please let me know.

Kind regards

Re: PTP clock source on RT106x

Omar_Anguiano — Thu, 25 Jul 2024 19:13:29 GMT

You can use another clock source for Enet_ref such as the 125Hz source wich frequency can be updated. To do that please use Config tool in MCUXPresso.

Best regards,
Omar