txt: ## dist_zef-jonathanstowe-RPi-Device-SMBus.md
  # RPi::Device::SMBus
  
  i²c on Raspberry Pi for Raku
  
  ![Build Status](https://github.com/jonathanstowe/RPi-Device-SMBus/workflows/CI/badge.svg)
  
  ## 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](https://github.com/jonathanstowe/RPi-Device-SMBus/issues)
  
  ## Licence
  
  This is free software.
  
  Please see the <LICENCE> file in the distribution
  
  © Jonathan Stowe 2015 - 2021
  