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LMI2
LMI2
Senior III
July 1, 2020
Question

How high a clock frequency does Power Regulator Voltage Scale 1 support? For STM32H750

  • July 1, 2020
  • 3 replies
  • 944 views

I tried to search for Power Regulator Voltage Scale in several PDFs but found only power regulator. Those talks voltage levels and perfomance levels but give no numbers.

I ask because I tried 200MHz with Scale 1 and the CPU was dead. I can program it again I quess, but some numbers would be nice to have. Besides, I thought that CubeMx would notice those kinds of errors.

75MHz with level 1 seems to work well.

This topic has been closed for replies.

3 replies

waclawek.jan
waclawek.jan
Super User
July 1, 2020

Which clock frequency? What does the datasheet say?

JW

LMI2
LMI2Author
Senior III
July 1, 2020

STM32H750 should be able to work with 400MHz -480MHz clock.

Power Regulator Voltage Scale must be a new feature, I can't find good information about them. All I see that there are several Power Regulator voltages.

This problem may have solved itself. I rebooted my PC (and the USB ports of course), and the board is now more responsive.

berendi
berendi
Principal
July 1, 2020

VOS Scale 1 supports system clock up to 400 MHz. See the PLL characteristics table in the datasheet.

I suspect that flash wait states are not set according to the selected clock speed. The default 0 wait state is guaranteed to work up to 70 MHz in VOS 1, it might work at 75 MHz with some luck, but not much higher. So the flash is not able to keep up with the core reading it and locks up. See 4.3.8 FLASH read operations in the reference manual.

LMI2
LMI2Author
Senior III
July 1, 2020

Good. Where is the speed range documented? I didn't find it. My problem seems to have been in the USB hub. I rebooted the PC and the Cpu works now.

Thank you all.

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