STM32H5 Interface With Gigabit Ethernet PHY device

[B.Michele]

Moved from MPUs forum.

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Hi, i must Use a Single Port Gigabit Ethernet PHY  that have a RGMII Gigabit Interface to connect a RMII 10/100 Mbit
Ethernet MAC interface of the STM32H563VI MCU. 

Do you think it is possible to connect a Gigabit PHY chip to the 100 Mbit H5 micros??? pin out,

Sure the final Ethernet Speed of the system, will be declasses to 10/100 Mbit. 

In particular I can't find where to connect the PA7 pin [RMII_CRS_DV] Carrier Sense... there is no CRS_DV output in the PHY gigabit device

Thank you very much

[mƎALLEm]

Hello,

STM32 MCUs don't support Ethernet Gigabit. Only MPU family does: STM32MP1xx, STM32MP2xx

[PatrickF]

Not possible to connect RGMII PHY to an RMII interface. They are using different signals and clocks.

You need to look for a RMII PHY.

Regards.

[B.Michele]

Good evening SofLit,

Thank you for your answer;  Yes I Know that STM32H563VI  MCU haven't the Gigabit Interface but only the 10/100 Mbit/s Fast Ethernet Like All H5-H7 ecc.. STM Arm processor
For me it' Ok to have only 100 Mbit/s speed  But I want Interface the PHY Phisical Layer to magnetic and RJ45 Copper Ethernet line With a New Chip Gigabit that have RGMII line.

So i want interface the RMII or MII Interface of STM H5 With a RGMII PHY Chip;

Is it possible to adapt the signals together with some I/O pins to drive the RGMII interface by downgrading it to max 100 Mbit??

Thank's

[B.Michele]

Good evening PatrickF,

Thank you for your answer;  Ok The H5 MCU haven't the RGMII but only  the SMI, MII, RMII, interface.

I was wondering if it's not really possible to adapt the signals together with some I/O pins to drive the RGMII interface by downgrading it to max 100 Mbit??   with the RMII Or MII H5 pinout and some other I/O pin.... 
downgrading the clock to 25 MHz I think, or whatever it takes....

Thank's

[PatrickF]

Hi, @B.Michele 

sorry to be rude, but I fear there is no way, they are too different.

RGMII PHY could run on 100Mbit/s link, but it is still using RGMII protocol.

Either you use an RMII PHY with STM32H5, or use an STM32 having RGMII capabilities (STM32N6, STM32MP1, STM32MP2 families).

Regards.

[Pavel A.]

@B.Michele Please ask the vendor of the PHY if they support RMII. We have successfully connected STM32H753 to a 10/100/GB Broadcom switch chip, in 100 M RMII mode.

[B.Michele]

Thank you @PatrickF

Ok, thanks for the advice, so ultimately the "Copper" or "Fiber" Ethernet PHY device must support one of the two protocols of the H5: 'MII' or 'RMII'

The H5 MCU have only the MII and RMII Media Independent Interface that i must use. Together with the SMI serial signal realize the MAC interface for the PHY device.

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So the last question for reflection is that with a RMII MAC and a PHY that supports both copper and fiber I can achieve 100 Mbps with both magnetic and RJ45 and optical fiber?? with only RMII protocol ??

Thank's @PatrickF

[B.Michele]

Thank you @Pavel A.,

Thanks for your suggestion, certainly i see the opinion too with my MaxLinear Single Port Gigabit Ethernet PHY with RGMII Or SGMII interface.  H7 & H5 I think they have the same Ethernet MAC interface.
I can only ask you the brand of the PHY chips ??

Thank's

[Pavel A.]

> I can only ask you the brand of the PHY chips

For bring-up we used PHYs similar to LAN8742.