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) ⇒ 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 and :RTSCTS (default :NONE)

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

    Number of data bits (default 8)



49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
 
# File 'lib/cosmos/streams/serial_stream.rb', line 49

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



139
140
141
 
# File 'lib/cosmos/streams/serial_stream.rb', line 139

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



145
146
147
 
# File 'lib/cosmos/streams/serial_stream.rb', line 145

def connected?
  @connected
end

#disconnect ⇒ Object

Disconnect by closing the serial ports



150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
 
# File 'lib/cosmos/streams/serial_stream.rb', line 150

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



114
115
116
117
118
119
 
# File 'lib/cosmos/streams/serial_stream.rb', line 114

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



122
123
124
125
126
127
 
# File 'lib/cosmos/streams/serial_stream.rb', line 122

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



130
131
132
133
134
135
136
 
# File 'lib/cosmos/streams/serial_stream.rb', line 130

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