Need Guidance for Retrigger (Falling Edge) GP14 by using RP 2040 PICO

I use 4 PICOs RP2040, a total of 16 ADC channels (4 ADC channels
per PICO) where the trigger signal (reference voltage) is connected to GP14. I’ve programmed the Picomite to set a trigger value for a falling edge, which means the trigger should activate when the signal reaches 0.8 V. However, I’m encountering an issue where the output voltages I’m getting are higher than expected—they should be lower or close to 0.8 V. The trigger signal frequency is set at 360 Hz, and the input voltage is a 1.2 V AC sine wave at the same frequency. Currently, the output voltages from all ADC channels are between 0.85 and 0.87 V. When I increase the frequency to 400 Hz, 450 Hz, or 500 Hz, the output voltages rise even higher, which is confusing. Could you please help me identify where I might be making a mistake?
I aim to capture the input signal precisely at the point where it crosses the trigger voltage of 0.8 V on a falling edge. To achieve this, I set the offset to zero (minimum). I connected an oscilloscope in DC coupling mode on the input side to monitor the amplitude and frequency of the input voltage. Since the trigger is set for the falling edge, which means the system should capture the signal as it transitions from rising to falling and reaches the trigger level, I expect the captured voltage to be less than 0.8 V.
Kind regardsHasham

You may have the wrong forum. This forum deals with the use & installation of Linuxcnc.