This gem aims to provide a Unified method of talking to SPI devices on a variety of hardware. This is mainly aimed at a range of Small Board Computers (SBCs) such as the Raspberry Pi and C.H.I.P. computers.
Currently only the Linux spidev kernel interface is implimented however the code is designed to make adding other drivers a simple process. It should then be possible to choose the correct driver for the hardware without having to re-write code.
Add this line to your application's Gemfile:
And then execute:
Or install it yourself as:
$ gem install spi
You may need to enable the SPI device on your hardware and/or load the kernel module. On the Raspberry Pi SPI can be enabled through raspi-cofig On the C.H.I.P. SPI can be loaded by importing the SPI DTB
After doing this you should find one or more devices in /dev
[email protected]:~ $ ls /dev/spi* /dev/spidev32766.0
To use the default (SPIdev) driver you can specify
require "bundler/setup" require "spi" s=SPI.new(device: '/dev/spidev32766.0') s.speed=500000 s.xfer(txdata: [0x10,0x00])
Currently SPIdev is the only driver.
Simple Testing of just the SPIdev Driver with an RFM69
require "bundler/setup" require "spi" require 'spi/driver/spidev' s=SPI::Driver::SPIdev.new(device: '/dev/spidev32766.0') s.speed=500000 s.xfer(txdata: [0x10,0x00])
This should result in a 2 byte array with the 2nd value reporting 36 (0x24)
In simple terms (assuming a more recent (december 2016 or later 4.4 image)
sudo mkdir -p /sys/kernel/config/device-tree/overlays/spi sudo cp /lib/firmware/nextthingco/chip/sample-spi.dtbo /sys/kernel/config/device-tree/overlays/spi/dtbo
After checking out the repo, run
bin/setup to install dependencies. You can also run
bin/console for an interactive prompt that will allow you to experiment.
To install this gem onto your local machine, run
bundle exec rake install. To release a new version, update the version number in
version.rb, and then run
bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the
.gem file to rubygems.org.
Bug reports and pull requests are welcome on GitHub at https://github.com/m1ari/ruby-spi.