I want to run my microcontroller with the system clock derived from EXTAL and the RMII clock sourced from ENET_1588_CLKIN. I cannot run with a 50 MHz clock attached to EXTAL due to system requirements.
The KV58 reference manual inlcludes the following contradictory statements:
Which one is it? Can I have the microcontroller system clock derived from EXTAL and have the RMII clock sourced from a 50 MHz clock attached to ENET_1588_CLKIN?
Hello,
Is there any update to clarify this contradiction on the reference manual?
I am also trying to use RMII interface clock sourced from ENET_1588_CLKIN and having issues to make works properly, then I found this contradiction on the documentation and I am wondering if it might be the cause.
Thanks,
Hi Iain Rist,
The 50MHz external clock source can be connect to EXTAL pin.(The 48MHz allowable maximum clock of this source is a mistake in datasheet.)
You can refer the input clock circuit on TWR-KV58F220M:
I am not sure if the "Section 51.1.2 states that RMII_REF_CLK is internally tied to EXTAL." is documentation error or not.
Experiments may be needed to verify feasibility.
First select PTE26 to ENET_1588_CLKIN function via PORTE_PCR26[MUX].
Then select ENET_1588_CLKIN via SIM_SOPT2[RMIISRC].
Check whether the ENET_1588_CLKIN from PTE26 is able to clock RMII.
Best Regards,
Robin
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