i2cset

writes a value to a specified register of an I2C device

TLDR

Write to a register of an I2C device

$ i2cset [i2cbus] [device_address] [register_address] [value]

Write without confirmation prompt

$ i2cset -y [i2cbus] [device_address] [register_address] [value]

Write using a specific mode

$ i2cset [i2cbus] [device_address] [register_address] [value] [b|w|c|s|i]

SYNOPSIS

i2cset [options] i2cbus deviceaddress registeraddress value [mode]

i2cset writes a value to a specified register of an I2C device. This allows configuration of I2C peripherals, setting parameters, or controlling device behavior.All addresses and values should be specified in hexadecimal notation. The command will prompt for confirmation before writing unless the -y flag is used.

PARAMETERS

-y

Disable interactive confirmation (dangerous on some hardware)

Byte mode - write single byte (default)

Word mode - write 16-bit value

Consecutive byte mode

SMBus block mode

I2C block mode

INSTALL

sudo apt install i2c-tools

sudo dnf install i2c-tools

sudo pacman -S i2c-tools

sudo apk add i2c-tools

sudo zypper install i2c-tools

brew install i2c-tools

nix profile install nixpkgs#i2c-tools

CAVEATS

Writing to I2C registers can cause hardware damage or unexpected behavior. Always verify device addresses and register meanings before writing. Some devices may become unresponsive or require power cycling after incorrect writes. Requires root privileges or i2c group membership.

HISTORY

i2cset is part of the i2c-tools package, providing userspace write access to I2C devices. The I2C protocol was developed by Philips (now NXP) in 1982 for low-speed peripheral communication.