ESP32 - Measuring 3.0V on some GPIOS
Posted: Wed Apr 20, 2022 5:11 pm
by velmurugan7kmvs
- GPIO_Measurement.PNG (28.94 KiB) Viewed 1553 times
Hi All, Why do i measure only 3.0V on some GPIOs?
Re: ESP32 - Measuring 3.0V on some GPIOS
Posted: Wed Apr 20, 2022 5:31 pm
by mikemoy
Have you tried say a 10k resistor ?
Re: ESP32 - Measuring 3.0V on some GPIOS
Posted: Thu Apr 21, 2022 1:00 am
by ESP_Sprite
General measuring instruments (like a multimeter or a scope) do not have infinite input impedance, and show up as a high-valued (e.g 10Mohm) resistor to ground. With your 1Mohm resistor, this forms a voltage divider, and 1Mohm/10Mohm would indeed give you 3.0V. GPIO15 is a bootstrap pin and may still have an internal (50K-ish) pullup enabled, hence it still reading 3.3V.