Low Amplitude and DC Offset on the Crystal

[drad1]

Hello, 

We use STM32H755 with a 25MHz crystal oscillator connected to OSC32_IN and OSC32_OUT OSC_IN and OSC_OUT pins. Probed on the bench, I see a sine wave with a DC offset and low amplitude. Can you comment if the attached waveform looks okay? My expectation was that the sine wave would swing from 0V to around 3.3V, and that there should be no added DC offset. 

Thanks!

[AScha.3]

No, that's ok.

The amplitude depends on the drive strength, so if you set high drive level, amplitude is bigger, but consuming more energy from the driver.

[TDK]

This is not sufficient as-is.

However, the probe adds capacitance. It's possible that the signal is fine without the probe attached. Your probe probably has a 10x mode which should be used to reduce (but not eliminate) the capacitive load.

Additionally, and most critically:

> STM32H755 with a 25MHz crystal oscillator connected to OSC32_IN and OSC32_OUT pins

The OSC32 pins expect a ~32 kHz signal. A 24 MHz signal won't do.

[drad1]

Just to address the typo on my end: It is connected to OSC_IN and OSC_OUT pins.