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I2C not working due to the incorrect voltage level

Posted: Thu Oct 31, 2019 9:52 pm
by marko.brelak
Dear colleagues,

I am working for quite some time with the ESP32, using esp-idf. So far, it was a pleasant experience both with the esp hardware and the esp-idf. But now I have some problems with the I2C bus, to be more concrete, I have an i2c scanner and not a single slave has responded. When looked on the oscilloscope, it can be noticed that the SCL signal has a rail-to-rail transition (3.3V) while the SDA can not reach the 3.3V when released, but stays on some ~0.5V. I have a 4.7K resistor pulled up to the 3.3V on both lines.

Have you ever experienced something like this, is it possible that the pin is damaged?

Re: I2C not working due to the incorrect voltage level

Posted: Fri Nov 01, 2019 1:59 am
by mikemoy
What pins are you using for SCL and SDA ?

Re: I2C not working due to the incorrect voltage level

Posted: Sun Nov 10, 2019 6:24 pm
by marko.brelak
After a couple of days of debugging and trying to find the cause of the error, we found out that the factory rotated the sensor DPS310. That means that the SCK was on VDD, and SDA on GND, that caused the faulty condition.

Re: I2C not working due to the incorrect voltage level

Posted: Wed Jul 15, 2020 11:17 am
by ilopata1
Seeing a similar problem here. Could you let me know who manufactured your boards?