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.TH I2CDUMP 8 "May 2008" |
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.SH NAME |
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i2cdump \- examine I2C registers |
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.SH SYNOPSIS |
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.B i2cdump |
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.RB [ -f ] |
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.RB [ "-r first-last" ] |
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.RB [ -y ] |
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.I i2cbus |
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.I address |
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.RI [ "mode " [ "bank " [ bankreg ]]] |
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.br |
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.B i2cdump |
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.B -V |
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.SH DESCRIPTION |
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i2cdump is a small helper program to examine registers |
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visible through the I2C bus. |
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.SH OPTIONS |
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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 -f |
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Force access to the device even if it is already busy. By default, i2cdump |
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will refuse to access a device which is already under the control of a |
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kernel driver. Using this flag is dangerous, it can seriously confuse the |
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kernel driver in question. It can also cause i2cdump to return invalid |
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results. So use at your own risk and only if you know what you're doing. |
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.TP |
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.B -r first-last |
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Limit the range of registers being accessed. This option is only available |
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with modes \fBb\fP, \fBw\fP, \fBc\fP and \fBW\fP. For mode \fBW\fP, |
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\fBfirst\fR must be even and \fBlast\fR must be odd. |
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.TP |
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.B -y |
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Disable interactive mode. By default, i2cdump 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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.PP |
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At least two options must be provided to i2cdump. \fIi2cbus\fR indicates the |
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number or name of the I2C bus to be scanned. This number should correspond to one |
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of the busses listed by \fIi2cdetect -l\fR. \fIaddress\fR indicates the |
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address to be scanned on that bus, and is an integer between 0x03 and 0x77. |
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.PP |
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The \fImode\fR parameter, if specified, is one of the letters \fBb\fP, \fBw\fP, |
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\fBs\fP, or \fBi\fP, corresponding to a read size of a single byte, a 16-bit |
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word, an SMBus block, an I2C block, respectively. The \fBc\fP mode is a |
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little different, it reads all bytes consecutively, and is useful for chips that |
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have an address auto-increment feature, such as EEPROMs. The \fBW\fP mode is |
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also special, it is similar to \fBw\fP except that a read command will only |
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be issued on even register addresses; this is again mainly useful for EEPROMs. |
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.PP |
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A \fBp\fP can also be appended to the \fImode\fR parameter (except for |
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\fBi\fP and \fBW\fP) to enable PEC. If the \fImode\fR parameter is omitted, |
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i2cdump defaults to byte access without PEC. |
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.PP |
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The \fIbank\fR and \fIbankreg\fR parameters are useful on the W83781D and |
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similar chips (at the time of writing, all Winbond and Asus chips). |
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\fIbank\fR is an integer between 0 and 7, and \fIbankreg\fR is an integer |
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between 0x00 and 0xFF (default value: 0x4E). The W83781D data sheet has more |
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information on bank selection. |
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.SH WARNING |
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i2cdump can be dangerous if used improperly. Most notably, the \fBc\fP mode |
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starts with WRITING a byte to the chip. On most chips it will be stored in the |
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address pointer register, which is OK, but some chips with a single register |
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or no (visible) register at all will most likely see this as a real WRITE, |
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resulting in possible misbehavior or corruption. Do not use i2cdump |
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on random addresses. Anyway, it is of little use unless you have good |
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knowledge of the chip you're working with and an idea of what you are looking |
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for. |
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.SH SEE ALSO |
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i2cset(8), i2cdetect(8), isadump(8) |
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.SH AUTHOR |
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Frodo Looijaard, Mark D. Studebaker and Jean Delvare |
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|
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This manual page was originally written by David Z Maze <dmaze@debian.org> for |
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the Debian GNU/Linux system. |
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