NAME

    Device::SMBus - Control and read hardware devices with i2c(SMBus)

VERSION

    version 1.11

SYNOPSIS

       use Device::SMBus;
       $dev = Device::SMBus->new(
         I2CBusDevicePath => '/dev/i2c-1',
         I2CDeviceAddress => 0x1e,
       );
       print $dev->readByteData(0x20);

DESCRIPTION

    This is a perl interface to smbus interface using libi2c-dev library.

    Prerequisites:

    For Debian and derivative distros(including raspbian) use the
    following to install dependencies:

      sudo apt-get install libi2c-dev i2c-tools build-essential

    If you are using Angstrom Linux use the following:

      opkg install i2c-tools
      opkg install i2c-tools-dev

    For ArchLINUX use the following steps:

      pacman -S base-devel
      pacman -S i2c-tools

    Special Instructions for enabling the I2C driver on a Raspberry Pi:

    You will need to comment out the driver from the blacklist. currently
    the I2C driver isn't being loaded.

         sudo vim /etc/modprobe.d/raspi-blacklist.conf

    Replace this line

         blacklist i2c-bcm2708

    with this

         #blacklist i2c-bcm2708

    You now need to edit the modules conf file.

         sudo vim /etc/modules

    Add these two lines;

         i2c-dev
         i2c-bcm2708

    Now run this command(replace 1 with 0 for older model Pi)

         sudo i2cdetect -y 1

    If that doesnt work on your system you may alternatively use this:

         sudo i2cdetect -r 1

    you should now see the addresses of the i2c devices connected to your
    i2c bus

ATTRIBUTES

 I2CBusDevicePath

    Device path of the I2C Device.

     * On Raspberry Pi Model A this would usually be /dev/i2c-0 if you are using the default pins.
     * On Raspberry Pi Model B this would usually be /dev/i2c-1 if you are using the default pins.

 I2CDeviceAddress

    This is the Address of the device on the I2C bus, this is usually
    available in the device Datasheet.

     * for /dev/i2c-0 look at output of `sudo i2cdetect -y 0' 
     * for /dev/i2c-1 look at output of `sudo i2cdetect -y 1' 

METHODS

 fileError

    returns IO::Handle->error() for the device handle since the last
    clearerr

 writeQuick

     $self->writeQuick($value)

    This sends a single bit to the device, at the place of the Rd/Wr bit.

 readByte

     $self->readByte()

    This reads a single byte from a device, without specifying a device
    register. Some devices are so simple that this interface is enough;
    for others, it is a shorthand if you want to read the same register
    as in the previous SMBus command

 writeByte

     $self->writeByte()

    This operation is the reverse of readByte: it sends a single byte to
    a device.

 readByteData

     $self->readByteData($register_address)

    This reads a single byte from a device, from a designated register.
    The register is specified through the Comm byte.

 writeByteData

     $self->writeByteData($register_address,$value)

    This writes a single byte to a device, to a designated register. The
    register is specified through the Comm byte. This is the opposite of
    the Read Byte operation.

 readNBytes

     $self->readNBytes($lowest_byte_address, $number_of_bytes);

    Read together N bytes of Data in linear register order. i.e. to read
    from 0x28,0x29,0x2a

     $self->readNBytes(0x28,3);

 readWordData

     $self->readWordData($register_address)

    This operation is very like Read Byte; again, data is read from a
    device, from a designated register that is specified through the Comm
    byte. But this time, the data is a complete word (16 bits).

 writeWordData

     $self->writeWordData($register_address,$value)

    This is the opposite of the Read Word operation. 16 bits of data is
    written to a device, to the designated register that is specified
    through the Comm byte.

 processCall

     $self->processCall($register_address,$value)

    This command selects a device register (through the Comm byte), sends
    16 bits of data to it, and reads 16 bits of data in return.

 writeBlockData

     $self->writeBlockData($register_address, $values)

    Writes a maximum of 32 bytes in a single block to the i2c device. The
    supplied $values should be an array ref containing the bytes to be
    written.

    The register address should be one that is at the beginning of a
    contiguous block of registers of equal length to the array of values
    passed. Not adhering to this will almost certainly result in
    unexpected behaviour in the device.

 readBlockData

     $self->readBlockData($register_address, $numBytes)

    Read $numBytes form the given register address, data is returned as
    array

    The register address is often 0x00 or the value your device expects

    common usage with micro controllers that receive and send large
    amounts of data: they almost always needs a 'command' to be written
    to them then they send a response: e.g: 1) send 'command' with
    writeBlockData, or writeByteData, for example 'get last telegram' 2)
    read 'response' with readBlockData of size $numBytes, controller is
    sending the last telegram

 DEMOLISH

    Destructor

CONSTANTS

 I2C_SLAVE

CREATING YOUR OWN CHIPSET DRIVERS

    Writing your own chipset driver for your own i2c devices is quiet
    simple. You just need to know the i2c address of your device and the
    registers that you need to read or write. Follow the manual at
    Device::SMBus::Manual.

NOTES

    I wrote this library for my Quadrotor project for controlling PWM
    Wave Generators ( ESC or DC motor controller ), Accelerometer,
    Gyroscope, Magnetometer, Altimeter, Temperature Sensor etc. However
    this module can also be used by anyone who wishes to read or control
    motherboard devices on I2C like laptop battery system, temperature or
    voltage sensors, fan controllers, lid switches, clock chips. Some PCI
    add in cards may connect to a SMBus segment.

    The SMBus was defined by Intel in 1995. It carries clock, data, and
    instructions and is based on Philips' I2C serial bus protocol. Its
    clock frequency range is 10 kHz to 100 kHz. (PMBus extends this to
    400 kHz.) Its voltage levels and timings are more strictly defined
    than those of I2C, but devices belonging to the two systems are often
    successfully mixed on the same bus. SMBus is used as an interconnect
    in several platform management standards including: ASF, DASH, IPMI.

    -wiki

USAGE

      * This module provides a simplified object oriented interface to
      the libi2c-dev library for accessing electronic peripherals
      connected on the I2C bus. It uses Moose.

SEE ALSO

      * Moose

      * IO::File

      * Fcntl

SUPPORT

 Bugs / Feature Requests

    Please report any bugs or feature requests through github at
    https://github.com/shantanubhadoria/perl-device-smbus/issues. You
    will be notified automatically of any progress on your issue.

 Source Code

    This is open source software. The code repository is available for
    public review and contribution under the terms of the license.

    https://github.com/shantanubhadoria/perl-device-smbus

      git clone git://github.com/shantanubhadoria/perl-device-smbus.git

AUTHOR

    Shantanu Bhadoria <shantanu@cpan.org>
    https://www.shantanubhadoria.com

CONTRIBUTORS

      * Jonathan Stowe <jns+git@gellyfish.co.uk>

      * Neil Bowers <neil@bowers.com>

      * Shantanu Bhadoria <shantanu att cpan dott org>

      * wfreller <wolfgang@freller.at>

COPYRIGHT AND LICENSE

    This software is copyright (c) 2015 by Shantanu Bhadoria.

    This is free software; you can redistribute it and/or modify it under
    the same terms as the Perl 5 programming language system itself.

