STM32H743BIT6: same clock source for both MCU and ethernet PHY?

[Meghna]

Hello, I am using STM32H743BIT6 as a MAC for DP83TC814R Ethernet PHY, I have one query regarding oscillator, I am using Ethernet in RMII slave mode which requires 50MHz reference clock, can i use the same clock which i am using for MCU HSE or should i use different one for EThernet PHY, But how the clocks can be synchronised in that case?

 

[MHoll.2]

Yes you can use the same clock (50MHz is the max clock allowed on OSC_IN), the synch is via the RMII_REF_CLK input pin of the STM32H7 (50MHz from PHY).

[Meghna]

Could you please elaborate on the pin numbers & names at both MAC & PHY side

MAC part number : STM32H743BIT6

PHY part number : DP83TC814R

[MHoll.2]

I will no do your work, please read the Datasheet / Reference manual for the STM32H74x and the DP83TC814.

Some small hint: The STM32 MAC with RMII interface needs the same clock as the PHY, see chapter 58.6.3 of the Reference manual (rm0433).