clock voltage is 1.68 on nucleo-f413zh

[zohbou1]

hey everyone im using nucleo board f413zh for an audio project and i have a weird clock voltage of 1.68 when i enable master clock  , the clock signal came from the st link to the mcu i have 2 board and in the two is the same problem  i check vdd and its 3.3v i dont know if the problem came from the firmware or from something else . in the screenshot you  can see the analogue value of the clock(i2s and mco) i have the last version of the st link firmware i wonder if someone can give me a hint to find  where the problem cam from. thanks 

 

 

[Tesla DeLorean]

The presentation isn't exactly compelling.. Do you have an actual oscilloscope you can illustrate this with?

[KnarfB · Accepted solution]

what freq do you expect and what is the sample rate of your scope? Looks like Shannon-Nyquist missed and clock averaging out at 3.3V/2.

hth

KnarfB

[TDK]

It's exactly what @KnarfB says. Your signal frequency is much higher than your analog sampling rate as shown by the screenshot you provided.

The digital sampling rate is much higher than the analog sampling rate on your logic analyzer. The setup tab will show you the rates.

[MKanc.1]

Not sure particularly about F413 but many nucleos i own has 8MHz clocks from its programmer part, or external crystal if exists. If you use a long cable, trace or try to drive a load with it, you get its average, which might be your problem. It might be nyquist frequency failure as explained.