Stamp C3U - Maximum GPIO input voltage?

  • Hi,

    I want to use the internal ADC of the Stamp C3U. What is the maximum voltage, that can be measured? 3,3V or 5V?
    I don't understand the meaning of the feature "Stamp-C3 contains 5V->3.3V DC/DC design". Does it mean, that there is a level shifter? Or does it mean, that the inputs are 5V tolerant? Or does it just mean, that 5V are accepted as power input?


  • Hello @o8of15

    DC/DC design in this case means there is a DC/DC converter for the power input so the M5StampC3U can be powered by USB / 5V. However the GPIOs are all 'naked' - there are no level shifters. And no, in general ESP32 GPIOs are not 5 V tolerant - 3.3 V is the maximum.

    Please also have a look at the schematic.


  • Hi Felix,
    thank you for your fast reply.
    I've used different Atmega, Attiny and STM32 based boards in the past, but new to ESP32. That's the reason for my "stupid" question. ;-)

    Thanks again.