I2C(3) (MPC8xx) I2C(3)
NAME
i2c - basic I2C interface
SYNOPSIS
bind -a #J[n] /dev
/dev/i2cnctl
/dev/i2cndata
DESCRIPTION
The I2C driver serves a one-level directory with two files
that give access to the target with address n on the
system's I2C bus. N is usually determined by the I2C device
manufacturer, and must be an even number from 0 to 254. I2C
gives address 0 special meaning as the `general call'
address. See an I2C specification for details.
The control file i2cnctl accepts commands to set the valid
address range and subaddressing mode for the corresponding
data file. The following control messages can be written to
it:
size nbytes
Set the logical size of the target device to nbytes
(default: 256). IO requests will be kept within this
limit. This value is also returned by Sys->stat as the
length of the data file.
subaddress
Cause subsequent reads and writes on the data file to
use I2C subaddressing. The target device must support
it. By default, the device is not subaddressed.
The data file i2cndata exchanges data with the slave device
with address n . Each write request transmits the given data
to the device. Each read request sends a receive request to
the device and returns the resulting data. If the I2C tar-
get is subaddressed, the current file offset gives the sub-
address (ranging from 0 to 255); otherwise the file offset
must be zero. Read and write requests are trimmed to the
size of the device.
SOURCE
/os/mpc/devi2c.c
/os/mpc/i2c.c
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