Provided by: i2c-tools_3.1.1-1_i386 bug


       i2cdump - examine I2C registers


       i2cdump   [-f]   [-r   first-last]  [-y]  i2cbus  address  [mode  [bank
       i2cdump -V


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


       -V     Display the version and exit.

       -f     Force  access  to  the  device  even  if  it is already busy. By
              default, i2cdump will refuse to access a device which is already
              under  the  control  of  a  kernel  driver.  Using  this flag is
              dangerous,  it  can  seriously  confuse  the  kernel  driver  in
              question.  It  can also cause i2cdump to return invalid results.
              So use at your own risk and only if you know what you're doing.

       -r first-last
              Limit the range of registers being accessed. This option is only
              available  with  modes  b, w, c and W. For mode W, first must be
              even and last must be odd.

       -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 or name 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 0x03 and 0x77.

       The  mode parameter, if specified, is one of the letters b, w, s, or i,
       corresponding 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,  such  as EEPROMs. The W mode is also
       special, it is similar to w except that a read  command  will  only  be
       issued  on  even  register  addresses;  this is again mainly useful for

       A p can also be appended to the mode parameter (except for i and W)  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.


       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 good knowledge of the chip you're working with  and  an
       idea of what you are looking for.


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


       Frodo Looijaard, Mark D. Studebaker and Jean Delvare

       This   manual   page   was   originally   written   by   David  Z  Maze
       <> for the Debian GNU/Linux system.

                                   May 2008                         I2CDUMP(8)