I2CDUMP(8)						      System Manager's Manual							I2CDUMP(8)

NAME

       i2cdump - examine I2C registers

SYNOPSIS

       i2cdump [-f] [-r first-last] [-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.

       -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 cor-
       respond 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 EEPROMs.

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

SEE ALSO

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

AUTHOR

       Frodo Looijaard, Mark D. Studebaker and Jean Delvare

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

								     May 2008								I2CDUMP(8)