1I2CDETECT(8)                System Manager's Manual               I2CDETECT(8)
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NAME

6       i2cdetect - detect I2C chips
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SYNOPSIS

10       i2cdetect [-y] [-a] [-q|-r] i2cbus [first last]
11       i2cdetect -F i2cbus
12       i2cdetect -V
13       i2cdetect -l
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DESCRIPTION

17       i2cdetect  is  a  userspace  program to scan an I2C bus for devices. It
18       outputs a table with the list of detected devices on the specified bus.
19       i2cbus  indicates  the  number of the I2C bus to be scanned, and should
20       correspond to one of the busses listed by i2cdetect -l.   The  optional
21       parameters  first  and  last restrict the scanning range (default: from
22       0x03 to 0x77).
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24       i2cdetect can also be used to query the functionalities of an  I2C  bus
25       (see option -F.)
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WARNING

29       This program can confuse your I2C bus, cause data loss and worse!
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INTERPRETING THE OUTPUT

33       Each  cell  in  the output table will contain one of the following sym‐
34       bols:
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36       · "--". The address was probed but no chip answered.
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38       · "UU". Probing was skipped, because this address is currently  in  use
39         by  a  driver.  This  strongly  suggests that there is a chip at this
40         address.
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42       · An address number in hexadecimal, e.g. "2d" or "4e". A chip was found
43         at this address.
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OPTIONS

47       -y     Disable  interactive mode. By default, i2cdetect will wait for a
48              confirmation from the user before messing with the I2C bus. When
49              this  flag is used, it will perform the operation directly. This
50              is mainly meant to be used in scripts.
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52       -a     Force scanning of non-regular addresses. Not recommended.
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54       -q     Use SMBus "quick write" commands for probing  (by  default,  the
55              command  used  is  the  one  believed  to be the safest for each
56              address).  Not recommended. This is known to corrupt  the  Atmel
57              AT24RF08 EEPROM found on many IBM Thinkpad laptops.
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59       -r     Use SMBus "read byte" commands for probing (by default, the com‐
60              mand used is  the  one  believed  to  be  the  safest  for  each
61              address).  Not recommended. This is known to lock SMBus on vari‐
62              ous write-only chips (most notably clock chips at address 0x69).
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64       -F     Display the list of functionalities implemented by  the  adapter
65              and exit.
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67       -V     Display the version and exit.
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69       -l     Output a list of installed busses.
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SEE ALSO

73       i2cdump(8), sensors-detect(8)
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AUTHOR

77       Frodo   Looijaard,   Mark  D.  Studebaker,  and  the  lm_sensors  group
78       http://www.lm-sensors.org/ This manual page  was  written  by  Aurelien
79       Jarno  <aurel32@debian.org>,  for  the  Debian GNU/Linux system. It was
80       then reviewed by the lm_sensors team and is now part of the  lm_sensors
81       source distribution.
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85                                 October 2006                     I2CDETECT(8)
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