Operating with Data Streams

Generally, flexible device driver operates with two data streams:

  • Outgoing data stream (data outgoing via TCP connection, sequence of sent UDP datagrams or data sent through a Serial port)
  • Incoming data stream (data incoming via TCP connection, sequence of incoming UDP datagrams or data received from a Serial port)

Both streams are initialized during device connection state of the synchronization cycle. This assumes establishing a TCP connection or opening a serial port.

Once connection stage is successfully completed, driver performs two parallel activities:

  • Writing data to outgoing stream upon:
    • Device variable read/write operations
    • Function execution operations
    • Other stages of synchronization cycle (metadata reading, synchronization starting/stopping, etc.)
  • Reading data from the incoming stream, splitting it into protocol units and associating those units with:
    • Replies to commands sent earlier (variable read/write commands, function execution commands, commands sent on other stages of synchronization, such as metadata reading)
    • Asynchronous device notifications that are converted to device events

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