Qwiic pHAT for Raspberry Pi Hookup Guide
bboyho, 
Englandsaurus 
Scanning for I2C Devices
The best place to start would be to scan for an I2C device on the bus.
Configuration
Like the SPI peripheral, I2C is not turned on by default. Again, we can use raspi-config to enable it.
- Run
sudo raspi-config. - Use the down arrow to select
5 Interfacing Options - Arrow down to
P5 I2C. - Select
yeswhen it asks you to enable I2C - Select
OKand thenFinish
Once you return to terminal, enter this command:
language:bash
ls /dev/*i2c*
The Pi should respond with:
language:bash
/dev/i2c-1
Which represents the user-mode I2C interface.
Utilities
There is a set of command-line utility programs that can help get an I2C interface working. You can get them with the apt package manager. Enter the following command.
language:bash
sudo apt-get install -y i2c-tools
In particular, the i2cdetect program will probe all the addresses on a bus, and report whether any devices are present. Enter the following command in the command line. The -y flag will disable interactive mode so that you do not have to wait for confirmation. The 1 indicates that we are scanning for I2C devices on I2C bus 1 (e.g. i2c-1).
language:bash
i2cdetect -y 1
You will get an output from your Raspberry Pi similar to the output below.
language:bash
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: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: 60 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
This map indicates that there is a peripheral at address 0x60. Your address may vary depending on what is connected to the I2C bus. For advanced users, you can try to read and write its registers using the i2cget, i2cset and i2cdump commands.