I2C not working due to the incorrect voltage level

marko.brelak
Posts: 16
Joined: Wed Apr 10, 2019 1:26 pm

I2C not working due to the incorrect voltage level

Postby marko.brelak » Thu Oct 31, 2019 9:52 pm

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?
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mikemoy
Posts: 387
Joined: Fri Jan 12, 2018 9:10 pm

Re: I2C not working due to the incorrect voltage level

Postby mikemoy » Fri Nov 01, 2019 1:59 am

What pins are you using for SCL and SDA ?

marko.brelak
Posts: 16
Joined: Wed Apr 10, 2019 1:26 pm

Re: I2C not working due to the incorrect voltage level

Postby marko.brelak » Sun Nov 10, 2019 6:24 pm

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.

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