I get a return reading of .999756 on IO35 when the input voltage is only 3.17 volts. I had expected a reading that high when the input voltage was more like 3.3 volts. If I reduce the voltage to say 2.5, then the returned value is reasonably accurate. Reading the GPIO section of the Electromage website I get the notion that the input is good to 3.3V. Am I wrong? I went to the ESP32 datasheets and they are somewhat sketchy on the matter. I did find the following note, however:
When atten = 3 and the measurement result is above 3000 (voltage at approx. 2450 mV), the ADC accuracy will be worse than described in the table above.
Thanks!