RPi::Device::SMBus

i²c on Raspberry Pi for Raku

Synopsis

    use RPi::Device::SMBus;

    # Obviously you will need to actually read the data sheet of your device.
    my RPi::Device::SMBus $smbus = RPi::Device::SMBus.new(device => '/dev/i2c-1', address => 0x54);

    $smbus.write-byte(0x10);

    ....

Description

This is an SMBus/i²c interface that has been written and tested for the Raspberry Pi, however it uses a fairly generic POSIX interface so if your platform exposes the i²c interface as a character special device it may work.

In order to use this you will need to install and configure the i2c-dev kernel module and tools. On a default Debian image you should be able to just do:

sudo apt-get install libi2c-dev i2c-tools

And then edit the /etc/modules to add the modules by adding:

i2c-dev 
i2c-bcm2708

Or for a Raspberry Pi 3

i2c-dev
i2c-bcm2835

And then rebooting.

If you have a more recent raspbian you may alternatively be able to use raspi-config where you can turn on i2c under "Interfacing Options".

Typicaly the i2c device will be /dev/i2c-1 on a Raspberry Pi rev B. or v2 or /dev/i2c-0 on older versions.

You can determine the bus address of your device by doing:

sudo i2cdetect -y 1  # replace the 1 with a 0 for older versions

(Obviously the device should be connected, consult the manual for your device about this.)

Which should give you the hexadecimal address of your device. Some devices may not respond, so you may want to either check the data sheet of your device or read the i2cdetect manual page to get other options.

It should be noted that because there is no easy way of testing this without using physical devices then it may not work perfectly in all cases, but I'd be delighted to receive patches for any issues found.

Installation

Assuming you have a working Rakudo installation you should be able to install this with zef :

# From the source directory

zef install .

# Remote installation

zef install RPi::Device::SMBus

The tests are likely to completely fail on anything but a Raspberry Pi with the i²c configured as above.

Support

Suggestions/patches are welcomed via github

Licence

This is free software.

Please see the LICENCE file in the distribution