Why does STMCube MX limit the STM32H743ZI2 Nucleo board to 300MHz max MCU Frequency

[eg7963]

Hi There,

I'm trying to use the STM32H743Zi2 nucleo board for test purpose.

I configured the board with default settings ( when asked by CubeMX after selecting the board for a project). Means i basically did nothing (except assigning 1 ADC ppin and leaveing the rest untouched). I then tryed to configurate the Clock to use the 480MHz advertised in the datasheet, but Cube MX seems to be willing to accept only CPU Clocks below or equal to 300MHz.

1. There seem to be a rounding problem while setting up the PLL values, as in the ioc file they appear to come out with decimal values that don't exist.
2. main problem is still that even if setting values way below the 480MHz, CubeMX doesn't accept anything above 300MHz ( according to the hint given while hovering the error with the mouse)

I had that problem once with another board, and had no other choice than restarting the project from the scratch, but that didn't work out that time.

Cube MX is up to date(v6.7.0), and MCU Package also ( v1.11.0 for H7 MCU).

I didn't notice anything in the datasheet that would reduce drastically the maxoperation

speed of the device, but i might be wrong.

Is that a bug related to this specific MCU Package or is there something i missed here? Is there a work around to that Problem?

What happens if I generate the project with the errors still active, is there a correction/limitation somehow during the generation or are they configured so anyway?

[KDJEM.1 · Accepted solution]

Hello @eg7963​ ,

For STM32H743ZI, we have 2 revision (rev.Y and rev.V).

The max PLL clock depends for the MCU revisions and for power regulator voltage scale.

For more explanation please refer to table50. and table147. in the datasheet.

If you have STM32H743ZI rev V. in your board, and to get 480 MHz, please go to the RCC parameters in STM32CubeMX and check that the product revision is "V".

Then set the power regulator voltage scale to 0.

When your question is answered, please close this topic by choosing Select as Best. This will help other users find that answer faster.

Kaouthar

[eg7963]

Hi @KDJEM.1,

thanks for the answer.

Didn't notice that revision detail, and the LDO requierment in the datasheet.

LQFP144 package says revision V . So when changing the parameter as advised, I can now apply the full clock speed to the MCU and other peripherals.

Still got the decimal approximation problem , but i can live with that for now.

Thank you anyway.

[eg7963]

Ok the auto clock resolution removed the decimal part of the PLL.