i2cdump



I2CDUMP(8)                                                          I2CDUMP(8)




NAME

       i2cdump - examine I2C registers



SYNOPSIS

       i2cdump [-y] i2cbus address [mode] [bank [bankreg]]
       i2cdump -V



DESCRIPTION

       i2cdump  is a small helper program to examine registers visible through
       the I2C bus.



OPTIONS

       -V     Display the version and exit.

       -y     Disable interactive mode. By default, i2cdump 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.

       At  least two options must be provided to i2cdump. i2cbus indicates the
       number of the I2C bus to be scanned. This number should  correspond  to
       one of the busses listed by i2cdetect -l. address indicates the address
       to be scanned on that bus, and is an integer between 0x00 and 0x7F. The
       mode parameter, if specified, is one of the letters b, w, s, or i, cor-
       responding to a read size of a single byte, a  16-bit  word,  an  SMBus
       block, an I2C block, respectively. The c mode is a little different, it
       reads all bytes consecutively, and is useful for  chips  that  have  an
       address  auto-increment  feature.  A p can also be appended to the mode
       parameter to enable PEC. If the  mode  parameter  is  omitted,  i2cdump
       defaults to byte access without PEC.

       The  bank  and bankreg parameters are useful on the W83781D and similar
       chips (at the time of writing, all Winbond and Asus chips).  bank is an
       integer  between  0  and  7, and bankreg is an integer between 0x00 and
       0xFF (default value: 0x4E). The W83781D data sheet has more information
       on bank selection.



WARNING

       i2cdump  can  be dangerous if used improperly. Most notably, the c mode
       starts with WRITING a byte to the chip. On most chips it will be stored
       in  the  address  pointer  register, which is OK, but some chips with a
       single register or no (visible) register at all will  most  likely  see
       this  as a real WRITE, resulting in possible misbehavior or corruption.
       Do not use i2cdump on random addresses. Anyway, it  is  of  little  use
       unless  you have an idea of what you are looking for and have some gen-
       eral knowledge about hardware monitoring chips internals.



CONFORMING TO

       lm_sensors-2.x



SEE ALSO

       i2cset(8), i2cdetect(8), isadump(8)



AUTHOR

       Frodo  Looijaard,  Mark  D.  Studebaker,  and  the   lm_sensors   group
       http://www.lm-sensors.nu/  This  manual  page was originally written by
       David Z Maze <dmaze@debian.org> for the Debian GNU/Linux system. It was
       then  reviewed by the lm_sensors team and is now part of the lm_sensors
       source distribution.



                                  August 2004                       I2CDUMP(8)

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