Class: Cosmos::SerialStream

Inherits:
Stream show all
Defined in:
lib/cosmos/streams/serial_stream.rb

Overview

Stream that reads and writes to serial ports by using SerialDriver.

Instance Method Summary collapse

Constructor Details

#initialize(write_port_name, read_port_name, baud_rate, parity, stop_bits, write_timeout, read_timeout, flow_control = :NONE, data_bits = 8, struct = []) ⇒ SerialStream

Returns a new instance of SerialStream.

Parameters:

  • write_port_name (String) —

    The name of the serial port to write. Pass nil if the stream is to be read only. On Windows the port name is typically 'COMX' where X can be any port number. On UNIX the port name is typically a device such as '/dev/ttyS0'.

  • read_port_name (String) —

    The name of the serial port to read. Pass nil if the stream is to be read only. On Windows the port name is typically 'COMX' where X can be any port number. On UNIX the port name is typically a device such as '/dev/ttyS0'.

  • baud_rate (Integer) —

    The serial port baud rate

  • parity (Symbol) —

    Must be :NONE, :EVEN, or :ODD

  • stop_bits (Integer) —

    Number of stop bits. Must be 1 or 2.

  • write_timeout (Integer) —

    Number of seconds to wait for the write to complete. Pass nil to create no timeout. The Cosmos::SerialDriver will continously try to send the data until it has been sent or an error occurs.

  • read_timeout (Integer) —

    Number of seconds to wait for the read to complete. Pass nil to create no timeout. The Cosmos::SerialDriver will continously try to read data until it has received data or an error occurs.

  • flow_control (Symbol) (defaults to: :NONE) —

    Currently supported :NONE, :RTSCTS (default :NONE)

  • data_bits (Integer) (defaults to: 8) —

    Number of data bits (default 8)

  • struct (Array) (defaults to: []) —

    Array of arrays of fields and values to set in the Windows DCB or POSIX structure



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# File 'lib/cosmos/streams/serial_stream.rb', line 42

def initialize(write_port_name,
               read_port_name,
               baud_rate,
               parity,
               stop_bits,
               write_timeout,
               read_timeout,
               flow_control = :NONE,
               data_bits = 8,
               struct = [])
  super()

  # The SerialDriver class will validate the parameters
  @write_port_name = ConfigParser.handle_nil(write_port_name)
  @read_port_name  = ConfigParser.handle_nil(read_port_name)
  @baud_rate       = Integer(baud_rate)
  @parity          = parity
  @stop_bits       = stop_bits.to_i
  @write_timeout   = ConfigParser.handle_nil(write_timeout)
  @write_timeout   = @write_timeout.to_f if @write_timeout
  @read_timeout    = ConfigParser.handle_nil(read_timeout)
  @read_timeout    = @read_timeout.to_f if @read_timeout
  @flow_control    = flow_control.to_s.intern
  @data_bits       = data_bits.to_i

  if @write_port_name
    @write_serial_port = SerialDriver.new(@write_port_name,
                                          @baud_rate,
                                          @parity,
                                          @stop_bits,
                                          @write_timeout,
                                          @read_timeout,
                                          @flow_control,
                                          @data_bits,
                                          struct)
  else
    @write_serial_port = nil
  end
  if @read_port_name
    if @read_port_name == @write_port_name
      @read_serial_port = @write_serial_port
    else
      @read_serial_port = SerialDriver.new(@read_port_name,
                                           @baud_rate,
                                           @parity,
                                           @stop_bits,
                                           @write_timeout,
                                           @read_timeout,
                                           @flow_control,
                                           @data_bits,
                                           struct)
    end
  else
    @read_serial_port = nil
  end
  if @read_serial_port.nil? && @write_serial_port.nil?
    raise "Either a write port or read port must be given"
  end

  # We 'connect' when we create the stream
  @connected = true

  # Mutex on write is needed to protect from commands coming in from more
  # than one tool
  @write_mutex = Mutex.new
end

Instance Method Details

#connect ⇒ Object

Connect the stream



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# File 'lib/cosmos/streams/serial_stream.rb', line 132

def connect
  # N/A - Serial streams 'connect' on creation
end

#connected? ⇒ Boolean

Returns Whether the serial stream is connected to the serial port.

Returns:

  • (Boolean) —

    Whether the serial stream is connected to the serial port



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# File 'lib/cosmos/streams/serial_stream.rb', line 138

def connected?
  @connected
end

#disconnect ⇒ Object

Disconnect by closing the serial ports



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# File 'lib/cosmos/streams/serial_stream.rb', line 143

def disconnect
  if @connected
    begin
      @write_serial_port.close if @write_serial_port && !@write_serial_port.closed?
    rescue IOError
      # Ignore
    end

    begin
      @read_serial_port.close if @read_serial_port && !@read_serial_port.closed?
    rescue IOError
      # Ignore
    end
    @connected = false
  end
end

#read ⇒ String

Returns a binary string of data from the serial port

Returns:

  • (String) —

    Returns a binary string of data from the serial port



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# File 'lib/cosmos/streams/serial_stream.rb', line 110

def read
  raise "Attempt to read from write only stream" unless @read_serial_port
  # No read mutex is needed because reads happen serially
  @read_serial_port.read
end

#read_nonblock ⇒ String

Returns a binary string of data from the serial port without blocking

Returns:

  • (String) —

    Returns a binary string of data from the serial port without blocking



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# File 'lib/cosmos/streams/serial_stream.rb', line 117

def read_nonblock
  raise "Attempt to read from write only stream" unless @read_serial_port
  # No read mutex is needed because reads happen serially
  @read_serial_port.read_nonblock
end

#write(data) ⇒ Object

Parameters:

  • data (String) —

    A binary string of data to write to the serial port



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# File 'lib/cosmos/streams/serial_stream.rb', line 124

def write(data)
  raise "Attempt to write to read only stream" unless @write_serial_port
  @write_mutex.synchronize do
    @write_serial_port.write(data)
  end
end