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.TH I2CGET 8 "May 2008" |
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.SH "NAME" |
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i2cget \- read from I2C/SMBus chip registers |
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.SH SYNOPSIS |
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.B i2cget |
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.RB [ -f ] |
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.RB [ -y ] |
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.I i2cbus |
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.I chip-address |
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.RI [ "data-address " [ mode ]] |
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.br |
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.B i2cget |
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.B -V |
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.SH DESCRIPTION |
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i2cget is a small helper program to read registers visible through the I2C |
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bus (or SMBus). |
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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, i2cget |
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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 i2cget to return an invalid |
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value. 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 -y |
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Disable interactive mode. By default, i2cget 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. Use with caution. |
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.PP |
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There are two required options to i2cget. \fIi2cbus\fR indicates the number |
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or name of the I2C bus to be scanned. This number should correspond to one of |
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the busses listed by \fIi2cdetect -l\fR. \fIchip-address\fR specifies the |
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address of the chip on that bus, and is an integer between 0x03 and 0x77. |
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.PP |
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\fIdata-address\fR specifies the address on that chip to read from, and is |
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an integer between 0x00 and 0xFF. If omitted, the currently active register |
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will be read (if that makes sense for the considered chip). |
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.PP |
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The \fImode\fR parameter, if specified, is one of the letters \fBb\fP, |
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\fBw\fP or \fBc\fP, corresponding to a read byte data, a read word data or a |
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write byte/read byte transaction, respectively. A \fBp\fP can also be appended |
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to the \fImode\fR parameter to enable PEC. If the \fImode\fR parameter is omitted, |
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i2cget defaults to a read byte data transaction, unless \fIdata-address\fR is |
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also omitted, in which case the default (and only valid) transaction is a |
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single read byte. |
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.SH WARNING |
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i2cget can be extremely dangerous if used improperly. I2C and SMBus are designed |
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in such a way that an SMBus read transaction can be seen as a write transaction by |
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certain chips. This is particularly true if setting \fImode\fR to \fBcp\fP (write byte/read |
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byte with PEC). Be extremely careful using this program. |
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.SH SEE ALSO |
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i2cdump(8), i2cset(8) |
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.SH AUTHOR |
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Jean Delvare |
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This manual page was strongly inspired from those written by David Z Maze |
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for i2cset. |
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