Does sda (i2c) have 5 volt logic?

Question

Arduino

I bought an arduino clone , bme280 and a 5 to 3V converter from Chinese comrades . Connected the sensor through a converter to i2c (scl, sda on arduino) - does not work: #, 5v(V), 3v(V), SDA(V), SCL(V), T(C), mmHg, Alt(m) , %RH 0, 5.00, 3.33, 3.32, 4.98, 0.01, 162051, -81326.83, 0 1, 5.00, 3.32, 3.32, 4.98, 0.01, 162051, -81326.83, 0 2, 5.00, 3.32 , 162051, -81326.83, 0 Connected SDA directly - works: # v(V), 3v(V), SDA(V), SCL(V), T(C), mmHg, Alt(m), %RH 0, 5.00, 3.34, 2.92, 4.94, 26.64, 735, 287.20, 37 1, 5.00, 3.33, 2.91, 4.93, 26.63, 735, 286.14, 37
2, 5.00, 3.33, 2.91, 4.93, 26.63, 735, 286.41, 37
I tried to connect the SDA line to 5V through the register - the result, as in the first case, does not work.
I found out by chance that the voltage on the line is low
. Question: Is this a Chinese jamb or is it supposed to be like that? How can I fix it if I still need to connect devices with 5V logic to the i2c bus?

Answer 1

Does sda (i2c) have 5 volt logic?
Yes, usually. I2C contains two lines that are connected to the power line (+5V) through pull-up resistors.
Here in section 10 it is mentioned about 3V sources, but only "I2C devices with fixed input levels of 1.5V and 3V can have their own supply voltages."
Can you link to all the modules used?
Maybe there is bme280 5V compatible, what kind of level converter, etc.
If all I2C devices are at 3.3V, then it is written here to really work with the module:
playground.arduino.cc/Main/I2CBi-directionalLevelS...
4.7k resistors, but they promise to work on the edge, based on the text.
Below in the same topic are options for pairing logics, this will be necessary if there are both 5V and 3.3V modules at the same time.