Not able to make STM32H745i Disco board running after a modification from SMPS to LDO

[mridul_xalten]

New question from this thread.

So in order to use both SMPS and LDO, given in board schematics,
I mounted SB6 and SB17 (SB44, SB46, L4 already mounted)
and removed SB5 and SB18 (rest already not mounted).

After than i flashed it with keeping the following settings.

Im still getting the same error. 

[LCE]

> So basically the HW is configured in SMPS.
> So in order to obtain 480MHz, what changes should i do to the hardware.
> Or is there any way i could do it without changing the hardware?

I think the SMPS is there exactly for using the maximum CPU speed of 480 MHz, because usually at fmax the power consumption is the highest, and the SMPS should have lower loss and thus heat generation than the internal LDO.

So my guess: after using the LDO the MCU is getting warmer than with SMPS.

[SofLit]

Check the VCORE voltage.

[SofLit]

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@LCE wrote:

I think the SMPS is there exactly for using the maximum CPU speed of 480 MHz,

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No. SMPS is not available in VOS0 (maximum 480Mhz). See this thread.

[LCE]

Thanks for the info!

Very interesting, why's that so? Any internal interference between SMPS and CPU at that clock rate?

@SofLit  

[SofLit]

Frankly, I don't have that information but VOS0 came after in rev V and it was not available in older die revisions like rev Y which have maximum CPU freq at 400MHz at VOS1.