Lesson 3.2.1 I2C Configuration

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Step 1: Enable the I2C port of your Raspberry Pi (If you have enabled it, skip this; if you do not know whether you have done that or not, please continue).

sudo raspi-config

5 Interfacing options

P5 I2C

<Yes>

<Yes>

<Ok>

<Finish>

<Yes> (If you do not see this page, continue to the next step)

Step 2: Check whether the i2c modules are loaded and active.

lsmod | grep i2c

Then the following codes will appear (the number may be different)

i2c_dev                     6276    0
i2c_bcm2708                 4121    0

Step 3: Install i2c-tools.

sudo apt-get install i2c-tools

Step 4: Check the address of the I2C device.

i2cdetect y 1      # For Raspberry Pi 2 and higher version
i2cdetect y 0      # For Raspberry Pi 1
pi@raspberrypi ~ $ i2cdetect -y 1
0 1 2 3 4 5 6 7 8 9 a b c d e f
00: — — — — — — — — — — — — —
10: — — — — — — — — — — — — — — — —
20: — — — — — — — — — — — — — — — —
30: — — — — — — — — — — — — — — — —
40: — — — — — — — — 48 — — — — — — —
50: — — — — — — — — — — — — — — — —
60: — — — — — — — — — — — — — — — —
70: — — — — — — — —

If there’s an I2C device connected, the results will be similar as shown above – since the address of the device is 0x48, 48 is printed.

Step 5:

For C language users: Install libi2c-dev.

sudo apt-get install libi2c-dev

For Python users: Install smbus for I2C.

sudo apt-get install python-smbus