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Ethernet example modification for STM32H745I-DISCO

DWill.4
Associate II

I came across this Ethernet example:

https://community.st.com/s/article/How-to-create-project-for-STM32H7-with-Ethernet-and-LwIP-stack-working

It is giving me an issue regarding configuring HSE in bypass mode. The maximum core frequency l can get is 96MHz compared to 400 MHz in the example.

Thank you for any assistance.

1 ACCEPTED SOLUTION

Accepted Solutions
Pavel A.
Evangelist III

> The maximum core frequency l can get is 96MHz compared to 400 MHz in the example.

This is a known issue. As too often with this forum, it's easier to reply again than search for the original answer.

Go to RCC parameters and select voltage scale 0. Then it will let you have 400 MHz.

0693W000008ySimQAE.png 

> none of the ST provided board examples using BYPASS mode.

Nucleo boards use BYPASS mode (at least some of them), and all Cube examples for these boards naturally use BYPASS mode.

-- pa

View solution in original post

4 REPLIES 4

None of the board examples use BYPASS mode, not sure the logic there.

Make sure HSE_VALUE is 25000000 in the stm32h7xx_hal_conf.h file

Use the SystemClock_Config() from

STM32Cube_FW_H7_V1.8.0\Projects\STM32H745I-DISCO\Applications\FatFs\FatFs_Shared_Device\CM7\Src\main.c

https://www.st.com/content/ccc/resource/technical/layouts_and_diagrams/schematic_pack/group1/e3/ee/b5/14/fe/97/43/3d/MB1381-H745XI-B02_Schematic/files/MB1381-H745XI-B02_Schematic.pdf/jcr:content/translations/en.MB1381-H745XI-B02_Schematic.pdf

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Thank you for replying.

You are correct about none of the ST provided board examples using BYPASS mode. I was trying to implement the user created example in the link. Your advice will set the core to 400MHz. What is your opinion on the linkerscript?

Pavel A.
Evangelist III

> The maximum core frequency l can get is 96MHz compared to 400 MHz in the example.

This is a known issue. As too often with this forum, it's easier to reply again than search for the original answer.

Go to RCC parameters and select voltage scale 0. Then it will let you have 400 MHz.

0693W000008ySimQAE.png 

> none of the ST provided board examples using BYPASS mode.

Nucleo boards use BYPASS mode (at least some of them), and all Cube examples for these boards naturally use BYPASS mode.

-- pa

Piranha
Chief II

Clive is right:

https://github.com/STMicroelectronics/STM32CubeH7/blob/ccb11556044540590ca6e45056e6b65cdca2deb2/Projects/STM32H745I-DISCO/Applications/FatFs/FatFs_Shared_Device/CM7/Src/main.c#L281

The value assigned should have been RCC_HSE_BYPASS. Well, that's just one of countless bugs in STM32 broken bloatware.