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TJung.2
TJung.2
Associate
July 15, 2020
Question

Is it possible to run the uC on a Nucleo-H745 board with 480Mhz?

  • July 15, 2020
  • 3 replies
  • 1140 views

I am working with the Nucleo-H745 and i am using STM32CubeIDE version 1.3.1. The datasheet stated that you need the LDO power supply to run the uC with full speed at 480Mhz. On the Nucleo board the SMPS only power supply is configured by default.

I created a new project and configured the Sysclock to 480Mhz without changing the power supply configuration. I did not see any problem. So my question ist:

Is this just good luck? I would expect to see any error (Hard Fault, Crash or any othe problem).

What are the real constraints or conditions that need to be met to run at 480Mhz?

The second point is, that Cube has no problem to generate this configuration. The generated Code does not avoid a configuration that is officially not allowed as stated in the data sheet.

So can i use this configuration or not?

Thanks for help.

Thomas

This topic has been closed for replies.

3 replies

TDK
TDK
July 15, 2020

Yes, look at the user manual for the configuration needed to run the LDO.

If it works without modification, you may just be getting lucky that problems are not yet occurring.

> The generated Code does not avoid a configuration that is officially not allowed as stated in the data sheet.

CubeMX has no way of knowing your hardware configuration.

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TJung.2
TJung.2Author
Associate
July 15, 2020

Hi TDK,

thanks for the answer. But in CubeMX you configure the Power Supply Mode (e.g. PWR_DIRECT_SMPS_SUPPLY or PWR_LDO_ONLY) and the SysClock. I agree that CubeMX does not know the hardware configuration but CubeMX could check the consitency of the settings (as it does it for many other conflicts as well).

So configuring PWR_DIRECT_SMPS_SUPPLY should conflict with SysClock frequencies higher than 400Mhz.

However.

Thanks

Thomas

Tesla DeLorean
Tesla DeLorean
Guru
July 15, 2020

The V-step devices are rated for 480 MHz operation, the LDO/SMPS settings need to be design appropriate, along with the VOS, PLL and FLASH Wait States to hit the numbers.

Older devices ran north of 500 MHz so the H7 has a quite high operational ceiling.

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