NAME

       i2cdetect - detect I2C chips

SYNOPSIS

       i2cdetect [-y] [-a] [-q|-r] i2cbus [first last]
       i2cdetect -F i2cbus
       i2cdetect -V
       i2cdetect -l

DESCRIPTION

       i2cdetect  is  a  userspace  program  to scan an I2C bus for devices. It outputs a table with the list of
       detected devices on the specified bus.  i2cbus indicates the number or name of the I2C bus to be scanned,
       and  should  correspond  to  one of the busses listed by i2cdetect -l.  The optional parameters first and
       last restrict the scanning range (default: from 0x08 to 0x77).

       As there is no standard I2C detection command, i2cdetect uses  arbitrary  SMBus  commands  (namely  SMBus
       quick  write  and  SMBus  receive  byte)  to  probe  for devices. By default, the command used is the one
       believed to be the safest for each address. See options -q and -r to change this behavior.

       i2cdetect can also be used to query the functionalities of an I2C bus (see option -F.)

WARNING

       This program can confuse your I2C bus, cause data loss and worse!

INTERPRETING THE OUTPUT

       Each cell in the output table will contain one of the following symbols:

       • "--". The address was probed but no chip answered.

       • "UU". Probing was skipped, because this address is currently in use by a driver. This strongly suggests
         that there is a chip at this address.

       • An address number in hexadecimal, e.g. "2d" or "4e". A chip was found at this address.

OPTIONS

       -y     Disable  interactive mode. By default, i2cdetect will wait for a confirmation from the user before
              messing with the I2C bus. When this flag is used, it will perform the operation directly. This  is
              mainly meant to be used in scripts.

       -a     Force scanning of non-regular addresses. Not recommended.

       -q     Use  SMBus "quick write" command for probing.  Not recommended. This is known to corrupt the Atmel
              AT24RF08 EEPROM found on many IBM Thinkpad laptops.

       -r     Use SMBus "receive byte" command for probing.  Not recommended. This is known  to  lock  SMBus  on
              various write-only chips (most notably clock chips at address 0x69).

       -F     Display the list of functionalities implemented by the adapter and exit.

       -V     Display the version and exit.

       -l     Output a list of installed busses.

EXAMPLES

       List all available I2C busses:
              # i2cdetect -l

       Immediately  scan  the standard addresses on I2C bus 9 (i2c-9), using the default method for each address
       (no user confirmation):
              # i2cdetect -y 9

       Query the functionalities of I2C bus 1 (i2c-1):
              # i2cdetect -F 1

       Scan addresses 0x10 to 0x17 on the I2C bus named "SMBus I801 adapter at efa0", using the  "receive  byte"
       method, after user confirmation:
              # i2cdetect -r "SMBus I801 adapter at efa0" 0x10 0x17

BUGS

       To report bugs or send fixes, please write to the Linux I2C mailing list <linux-i2c@vger.kernel.org> with
       Cc to the current maintainer: Jean Delvare <jdelvare@suse.de>.

SEE ALSO

       i2cdump(8), i2cget(8), i2cset(8), i2ctransfer(8), sensors-detect(8)

AUTHOR

       Frodo Looijaard, Mark D. Studebaker and Jean Delvare

       This manual page was originally written by Aurelien Jarno <aurel32@debian.org>, for the Debian  GNU/Linux
       system.

                                                  October 2017                                      I2CDETECT(8)