How to enable I2C

How to enable I2C funcion on Raspbian:

Please run the following command after you start the Raspberry Pi

sudo raspi-config

Select 5 Interfacing Options and then P5 I2C - Enable/Disable automatic loading. A prompt will appear asking Would you like the ARM I2C interface to be enabled?, select "Yes"

Select "OK"

Select "Finish" to return to the command line and reboot your raspberry pi.

sudo reboot

The Raspberry Pi will reboot and the 'i2c' interface will be enabled.

Then run the following command to check i2c port

sudo i2cdetect -y 1

The following is the I2C address of X729

pi@raspberrypi:~ $ sudo i2cdetect -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         -- -- -- -- -- -- -- -- 
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
30: -- -- -- -- -- -- 36 -- -- -- -- -- 3c -- -- -- 
40: 40 -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- 
60: -- -- -- -- -- -- -- -- 68 -- -- -- -- -- -- -- 
70: -- -- -- -- -- -- -- --    

#36 - the address of the battery fuel gauging chip
#3c - OLED display
#40 - TI INA219 12-bit current/voltage/power monitor
#68 - the address of the RTC chip

PS: Different hardware products may have different I2C addresses