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)