CP2112

Ruby wrapper for Silicon Laboratories CP2112 USB(HID) i2c/SMBus bridge library

Installation

Add this line to your application's Gemfile:

gem 'cp2112'

And then execute:

$ bundle

Or install it yourself as:

$ gem install cp2112

Usage

require 'cp2112'

dev = CP2112[0, 0x10C4, 0xEA90] # [index, vendor id, product id], [0x10C4, 0xEA90] are default parameters
raise unless dev.getPartNumber[0] == 0x0C # must always be 0xC0

gpio_new = [
  0x03, # GPIO.0-1: OUT, GPIO.2-7:IN
  0x00, # open-drain
  0x00, # GPIO
  0x00, # clkDiv
]
dev.setGpioConfig(*gpio_new)
raise unless (dev.getGpioConfig == gpio_new)
50.times{|i| # toggle GPIO.0-1
  bits = dev.readLatch[0]
  dev.writeLatch(bits ^ 0x03, 0x03)
  sleep(0.02)
}

# Read via I2C
i2c_read = proc{|addr, size| # addr is shifted by 1 bit (0bAAAA_AAAx, A=0/1, x=ignored)
  dev.readRequest(addr, size)
  dev.forceReadResponse(size)
  s0, buf, buf_read = dev.getReadResponse
  raise unless s0 == CP2112::Return_Code::HID_SMBUS_S0_COMPLETE
  buf[0...buf_read] # return is [byte, ...]
}

# Write via I2C
i2c_write = proc{|addr, data| # byte array data is expected; data = [byte, ...]
  dev.writeRequest(addr, data.pack('C*'), data.size)
  dev.transferStatusRequest
  s0, s1 = dev.getTransferStatusResponse
  raise unless s0 == CP2112::Return_Code::HID_SMBUS_S0_COMPLETE
}

# TODO: your i2c_read, i2c_write operation

dev.close

Development

After checking out the repo, run rake compile to install dependencies. Then, run rake spec to run the tests.

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.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/fenrir-naru/ruby-cp2112.