| .TH I2CDETECT 8 "October 2017" |
| .SH NAME |
| i2cdetect \- detect I2C chips |
| |
| .SH SYNOPSIS |
| .B i2cdetect |
| .RI [ -y ] |
| .RI [ -a ] |
| .RI [ -q | -r ] |
| .I i2cbus |
| .RI [ "first last" ] |
| .br |
| .B i2cdetect |
| .I -F |
| .I i2cbus |
| .br |
| .B i2cdetect |
| .I -V |
| .br |
| .B i2cdetect |
| .I -l |
| |
| .SH 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. |
| \fIi2cbus\fR indicates the number or name of the I2C bus to be scanned, and |
| should correspond to one of the busses listed by \fIi2cdetect -l\fR. |
| The optional parameters \fIfirst\fR and \fIlast\fR restrict the scanning |
| range (default: from 0x03 to 0x77). |
| .PP |
| 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 \fI-q\fR and \fI-r\fR to change this |
| behavior. |
| .PP |
| i2cdetect can also be used to query the functionalities of an I2C bus |
| (see option \fB-F\fP.) |
| |
| .SH WARNING |
| This program can confuse your I2C bus, cause data loss and worse! |
| |
| .SH INTERPRETING THE OUTPUT |
| Each cell in the output table will contain one of the following symbols: |
| .IP \(bu "\w'\(bu'u+1n" |
| "--". The address was probed but no chip answered. |
| .IP \(bu |
| "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. |
| .IP \(bu |
| An address number in hexadecimal, e.g. "2d" or "4e". A chip |
| was found at this address. |
| |
| .SH OPTIONS |
| .TP |
| .B "\-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. |
| .TP |
| .B "\-a" |
| Force scanning of non-regular addresses. Not recommended. |
| .TP |
| .B "\-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. |
| .TP |
| .B "\-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). |
| .TP |
| .B "\-F" |
| Display the list of functionalities implemented by the adapter and exit. |
| .TP |
| .B "\-V" |
| Display the version and exit. |
| .TP |
| .B "\-l" |
| Output a list of installed busses. |
| |
| .SH EXAMPLES |
| .PP |
| List all available I2C busses: |
| .nf |
| .RS |
| # i2cdetect -l |
| .RE |
| .fi |
| .PP |
| Immediately scan the standard addresses on I2C bus 9 (i2c-9), using the |
| default method for each address (no user confirmation): |
| .nf |
| .RS |
| # i2cdetect -y 9 |
| .RE |
| .fi |
| .PP |
| Query the functionalities of I2C bus 1 (i2c-1): |
| .nf |
| .RS |
| # i2cdetect -F 1 |
| .RE |
| .fi |
| .PP |
| Scan addresses 0x10 to 0x17 on the I2C bus named "SMBus I801 adapter at efa0", |
| using the "receive byte" method, after user confirmation: |
| .nf |
| .RS |
| # i2cdetect -r "SMBus I801 adapter at efa0" 0x10 0x17 |
| .RE |
| .fi |
| |
| .SH SEE ALSO |
| i2cdump(8), i2cget(8), i2cset(8), i2ctransfer(8), sensors-detect(8) |
| |
| .SH 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. |
