AnsweredAssumed Answered

STM32F429 HSE Crystal Amplitude

Question asked by bach.talk on Apr 13, 2016
Latest reply on Apr 14, 2016 by Mark Edwards
Has anyone ever had any problems with the amplitude of a clock signal when using an external crystal in HSE mode?

I have a board that I built that oscillates reliably and accurately, but the amplitude of the signal is too small.  It is centered about the midpoint voltage of 3.3, about 1.7 volts.  However, the peaks of the wave only reach about half a volt above and below the midpoint.  The DISCO board crystal is centered the same, but practically reaches the rails.  Playing with the values of the external capacitors has virtually no effect on the amplitude.  Are there any hardware or software configurations that would cause this.  Almost seems like the inverter in the microcontroller doesn't have the right supply, but I'm not sure how that could be.

Outcomes