HSE AC timings: tr(HSE), tf(HSE),THSE [STM32H743XGH6]

[NiM]

Do you know the specified values for tr, tf and THSE?

[KDJEM.1]

Hello @NiM ;

First of all, I apologize for my late reply.

The design is not sensitive to these parameters (tr and tf). 

In bypass mode the signal goes through a GPIO input. So for STM32H7 the constrains are the same as for a GPIO input.

You should respect the VIL and VIH threshold provided in table "Table 60. I/O static characteristics"

 

 

I hope this answer your request.

Thank you.

Kaouthar

 

[Andrew Neil]

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@KDJEM.1 wrote:

The design is not sensitive to these parameters. 

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So why does the datasheet call them out like this?

I think the datasheet needs an update to either remove them, or to say that they're unimportant.

[Andrew Neil]

T_HSE is just the period of the signal; ie, 1/f_{HSE_ext}