i2cdetect for device scanning in Raspberry Pi - Cheat Sheet & Quick Revision

Recall & Review

beginner

What is the purpose of the i2cdetect command on a Raspberry Pi?

The i2cdetect command scans the I2C bus on a Raspberry Pi to find connected I2C devices by showing their addresses.

beginner

How do you specify which I2C bus to scan using i2cdetect?

You add the bus number as an argument, for example, i2cdetect -y 1 scans bus number 1.

intermediate

What does the -y option do in the i2cdetect command?

The -y option disables interactive confirmation, so the scan runs without asking for permission.

beginner

What does it mean if i2cdetect shows a number at a certain address?

It means an I2C device is detected at that address on the bus.

intermediate

Why might i2cdetect show UU at some addresses?

UU means the address is in use by a driver and is busy, so i2cdetect cannot scan it.

What command scans I2C bus 1 for devices without asking for confirmation?

A i2cdetect -y 1

B i2cdetect 1

C i2cdetect -n 1

D i2cdetect -q 1

The -y option disables confirmation, so i2cdetect -y 1 scans bus 1 directly.

If i2cdetect shows a number at address 0x3C, what does it mean?

A No device found at 0x3C

B Address 0x3C is reserved

C Bus error at 0x3C

D Device detected at 0x3C

A number at an address means a device is detected there.

What does the UU symbol mean in i2cdetect output?

A No device detected

B Unknown device

C Device busy, address in use by driver

D Scan error

UU means the address is busy because a driver is using it.

Which bus number is commonly used for I2C on Raspberry Pi models after revision 2?

A 1

B 0

C 2

D 3

Bus 1 is the default I2C bus on Raspberry Pi models after revision 2.

Why should you run i2cdetect with sudo?

A To scan faster

B To access hardware bus permissions

C To save output to a file

D To update I2C drivers

Root permissions are needed to access the I2C hardware bus.

Explain how to use i2cdetect to find devices connected to your Raspberry Pi's I2C bus.

Think about the command format and what the output numbers mean.

Describe what the symbols and numbers in the i2cdetect output represent.

Focus on how to read the scan results.