The accuracy of the ADC is not accurate. I used the ADC0 channel 13 (PTC15) to detect the voltage. But I found that the 3.3V is the ADC value is 1023, (ten-bit resolution), but I detected 2.5V is the ADC value of 808, already The 0.1V is worse. What's even more strange is that the ADC value I detected for 0.5V is 78. This variation is already very large. Can help me check if my location problem or other problem, I will attach my code configuration
