NAME
Device::I2C - Control and read hardware devices with i2c(SMBus)
VERSION
version 0.06
SYNOPSIS
use Device::I2C;
use Fcntl;
$dev = Device::I2C->new('/dev/i2c-1', O_RDWR);
$dev->checkDevice(0x4c);
print $dev->readByteData(0x20);
DESCRIPTION
This is a perl interface to I2C 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
METHODS
fileError
returns IO::Handle->error() for the device handle since the last
clearerr
checkDevice
$self->checkDevice($register_address)
Check device
selectDevice
$self->selectDevice($register_address)
Select device
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 I2C 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
I2C_SLAVE_FORCE
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. Example in the
Device::I2C::ADV7611.
NOTES
Based on the Device::SMBus without Moo. On my device Moo based script
started 5 second.
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.
USAGE
* This module provides a simplified object oriented interface to the
libi2c-dev library for accessing electronic peripherals connected on
the I2C bus.
SEE ALSO
* Device::SMBus
* Device::I2C::ADV7611
* IO::File
* Fcntl
SUPPORT
Bugs / Feature Requests
Please report any bugs or feature requests through github at
https://github.com/sv99/perl-device-i2c/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/sv99/perl-device-i2c
git clone git://github.com/sv99/perl-device-i2c.git
AUTHOR
Slava Volkov <sv99@inbox.ru>
CONTRIBUTOR
Slava Volkov <svolkov att cpan dott org>
COPYRIGHT AND LICENSE
This software is copyright (c) 2016 by Slava Volkov.
This is free software; you can redistribute it and/or modify it under
the same terms as the Perl 5 programming language system itself.