STM32H745xI/G Ethernet Problem

[KTVT]

Hi everyone,

I am trying to run an ethernet phy (LAN8742Ai) using STM32H745. I can say that there is no major difference from the Nucleo ref. phy design. However, when i ping, i cannot get a response and the processor gets very hot. The phy and MCU blocks design as follows.

Thank you.

[SofLit]

Hello @KTVT  and welcome to the community,

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@KTVT wrote:

However, when i ping, i cannot get a response and the processor gets very hot. 

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When you say the MCU gets very hot, is it restricted to that specific application? what if you toggle a GPIO? do you have the same behavior? As could be something linked to the power settings/clock settings or power issue in the HW.

[STea]

Hello @KTVT ,

After a first examination of the published design here are some findings:

the GPIO configuration is not the same in fact you use:

PG 12 ------->ETH_TXD1

and the ref design of nucleo uses the following pins:

    /**ETH GPIO Configuration

    PC1     ------> ETH_MDC

    PA1     ------> ETH_REF_CLK

    PA2     ------> ETH_MDIO

    PA7     ------> ETH_CRS_DV

    PC4     ------> ETH_RXD0

    PC5     ------> ETH_RXD1

    PB13     ------> ETH_TXD1

    PG11     ------> ETH_TX_EN

    PG13     ------> ETH_TXD0

The oscillator configuration used in you design is not the same in the nucleo board, so I recommend you check if the PHY is clocked correctly by visualizing signals of Ethernet Ref clock and make sure you are getting the 50 Mhz to the MCU.
you use TPD4E02B04 before going to KMS-1102NL i don't get why you added this ESD protection which according to its datasheet is suited for:

Interfaces
– USB Type-C
– USB 3.1 Gen 2
– HDMI 2.0/1.4
– USB 3.0
– DisplayPort 1.3
– PCI Express 3.0
and not for Ethernet 
regarding the high temp issue, you are motioning we need some more insights it you RCC and smps ldo and other power related and clock related hardware insights and software to help you further 
regards