Differential ADC in stm32h7

[m_kalaiarasi]

I have recently purchased an STM32H753ZI board and want to configure the differential ADC to read signals directly from a function generator. I have configured it based on the following setup, but I am facing several issues with the output.

Issue 1: I am unable to read the ADC value properly. The negative side of the signal is getting clamped. How can I correct this?

Issue 2: When I input a 1V peak-to-peak sine wave to the differential ADC of the STM32H753ZI microcontroller, I am getting a square wave at the output. Why is this happening, and how can I fix it?

I have attached the output below when I am providing 1v peak to peak sine wave.

[TDK]

Are both sides of your signal within the voltage range 0 to VREF+? Negative voltages are not allowed, even in differential mode.

[m_kalaiarasi]

Hi ..My requirement is to read the sine signal of 1 volt peak to peak directly from function generator .But in differential mode can we able to measure the input signal directly without adding external dc offset(to upshift the signal from 0 to 500mV)?

why negative voltages are not allowed, could you elaborate it?

 what is difference between single and differential mode?

since i am beginner. Could you explain it

 

[TDK]

ICs in general cannot handle voltages outside of their power rails. This is reflected in the datasheet specifications.

[m_kalaiarasi]

I understand it.. but I am operating inside the power rails right?