Class: Hacklet::SerialConnection

Inherits:
Object
  • Object
show all
Defined in:
lib/hacklet/serial_connection.rb

Instance Method Summary collapse

Constructor Details

#initialize(logger, port = '/dev/ttyUSB0') ⇒ SerialConnection

Returns a new instance of SerialConnection.



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# File 'lib/hacklet/serial_connection.rb', line 5

def initialize(logger, port='/dev/ttyUSB0')
  @logger = logger
  @connection = Ftdi::Context.new
  @connection.usb_open(0x0403, 0x8c81)
  @connection.set_bitmode(0x00, Ftdi::BitbangMode[:reset])
  @connection.baudrate = 115200
  @connection.flowctrl = Ftdi::SIO_DISABLE_FLOW_CTRL
  @connection.dtr = 1
  @connection.rts = 1
  @receive_buffer = ""
end

Instance Method Details

#close ⇒ Object

Public: Closes the connection

Returns nothing.



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# File 'lib/hacklet/serial_connection.rb', line 20

def close
  @connection.usb_close
end

#receive(bytes) ⇒ Object

Public: Waits and receives the specified number of packets from the dongle.

bytes - The number of bytes to read.

Returns a binary string containing the response.



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# File 'lib/hacklet/serial_connection.rb', line 40

def receive(bytes)
  response = ""
  loop do
    if bytes <= @receive_buffer.bytesize
      array = @receive_buffer.bytes.to_a
      response = array[0..(bytes - 1)].pack('c*')
      @receive_buffer = array[(bytes)..-1].pack('c*')
      break
    end

    chunk = @connection.read_data
    if chunk.bytesize > 0
      @receive_buffer += chunk
    else
      sleep(0.1)
    end
  end
  @logger.debug("RX: #{unpack(response).inspect}")

  response
end

#transmit(command) ⇒ Object

Public: Transmits the packet to the dongle.

command - The binary string to send.

Returns the number of bytes written.



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# File 'lib/hacklet/serial_connection.rb', line 29

def transmit(command)
  @logger.debug("TX: #{unpack(command.to_binary_s).inspect}")
  @connection.write_data(command.to_binary_s)
end