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134 lines
3.4 KiB
134 lines
3.4 KiB
.TH I2CDETECT 8 "May 2022"
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.SH NAME
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i2cdetect \- detect I2C chips
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.SH SYNOPSIS
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.B i2cdetect
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.RI [ -y ]
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.RI [ -a ]
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.RI [ -q | -r ]
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.I i2cbus
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.RI [ "first last" ]
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.br
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.B i2cdetect
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.I -F
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.I i2cbus
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.br
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.B i2cdetect
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.I -V
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.br
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.B i2cdetect
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.I -h
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.br
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.B i2cdetect
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.I -l
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.SH DESCRIPTION
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i2cdetect is a userspace program to scan an I2C bus for devices. It
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outputs a table with the list of detected devices on the specified bus.
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\fIi2cbus\fR indicates the number or name of the I2C bus to be scanned, and
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should correspond to one of the busses listed by \fIi2cdetect -l\fR.
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The optional parameters \fIfirst\fR and \fIlast\fR restrict the scanning
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range (default: from 0x08 to 0x77).
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.PP
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As there is no standard I2C detection command, i2cdetect uses arbitrary
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SMBus commands (namely SMBus quick write and SMBus receive byte) to probe
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for devices. By default, the command used is the one believed to be the
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safest for each address. See options \fI-q\fR and \fI-r\fR to change this
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behavior.
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.PP
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i2cdetect can also be used to query the functionalities of an I2C bus
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(see option \fB-F\fP.)
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.SH WARNING
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This program can confuse your I2C bus, cause data loss and worse!
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.SH INTERPRETING THE OUTPUT
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Each cell in the output table will contain one of the following symbols:
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.IP \(bu "\w'\(bu'u+1n"
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"--". The address was probed but no chip answered.
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.IP \(bu
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"UU". Probing was skipped, because this address is currently in use by
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a driver. This strongly suggests that there is a chip at this address.
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.IP \(bu
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An address number in hexadecimal, e.g. "2d" or "4e". A chip
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was found at this address.
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.SH OPTIONS
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.TP
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.B "\-y"
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Disable interactive mode. By default, i2cdetect will wait for a confirmation
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from the user before messing with the I2C bus. When this flag is used, it
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will perform the operation directly. This is mainly meant to be used in
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scripts.
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.TP
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.B "\-a"
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Force scanning of non-regular addresses. Not recommended.
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.TP
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.B "\-q"
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Use SMBus "quick write" command for probing.
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Not recommended. This is known to corrupt the Atmel AT24RF08 EEPROM
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found on many IBM Thinkpad laptops.
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.TP
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.B "\-r"
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Use SMBus "receive byte" command for probing.
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Not recommended. This is known to lock SMBus on various write-only
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chips (most notably clock chips at address 0x69).
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.TP
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.B "\-F"
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Display the list of functionalities implemented by the adapter and exit.
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.TP
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.B "\-V"
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Display the version and exit.
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.TP
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.B "\-h"
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Display the help and exit.
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.TP
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.B "\-l"
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Output a list of installed busses.
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.SH EXAMPLES
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.PP
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List all available I2C busses:
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.nf
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.RS
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# i2cdetect -l
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.RE
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.fi
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.PP
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Immediately scan the standard addresses on I2C bus 9 (i2c-9), using the
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default method for each address (no user confirmation):
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.nf
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.RS
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# i2cdetect -y 9
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.RE
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.fi
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.PP
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Query the functionalities of I2C bus 1 (i2c-1):
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.nf
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.RS
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# i2cdetect -F 1
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.RE
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.fi
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.PP
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Scan addresses 0x10 to 0x17 on the I2C bus named "SMBus I801 adapter at efa0",
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using the "receive byte" method, after user confirmation:
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.nf
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.RS
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# i2cdetect -r "SMBus I801 adapter at efa0" 0x10 0x17
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.RE
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.fi
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.SH BUGS
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To report bugs or send fixes, please write to the Linux I2C mailing list
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<linux-i2c@vger.kernel.org> with Cc to the current maintainer:
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Jean Delvare <jdelvare@suse.de>.
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.SH SEE ALSO
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i2cdump(8), i2cget(8), i2cset(8), i2ctransfer(8), sensors-detect(8)
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.SH AUTHOR
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Frodo Looijaard, Mark D. Studebaker and Jean Delvare
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This manual page was originally written by Aurelien Jarno
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<aurel32@debian.org>, for the Debian GNU/Linux system.
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