// <CONSTRUCTORS>
/// <summary>
/// Initializes port but does not open it
/// </summary>
public COM()
{
// serial port
port = new SerialPort();
port.Parity = Global.Parity;
port.StopBits = Global.StopBits;
port.ReadTimeout = readTimeout;
port.WriteTimeout = Global.WriteTimeout;
port.BaudRate = Global.BaudRate;
port.DataBits = Global.DataBits;
port.NewLine = Global.NewLine;
// asynchronous transaction processing
comWorker.WorkerReportsProgress = false;
comWorker.WorkerSupportsCancellation = true;
comWorker.DoWork += ComWorker_DoWork;
comWorker.RunWorkerAsync();
// finite state machine
state = DeviceState.GetDefaultState(port);
newState = state;
}
// </PROPERTIES>
// <EVENT HANDLERS>
/// <summary>
/// The main loop that processes enqueued transactions
/// </summary>
/// <param name="sender">Background worker</param>
/// <param name="e">Event arguments</param>
private void ComWorker_DoWork(object sender, DoWorkEventArgs e)
{
while (!((BackgroundWorker)sender).CancellationPending)
{
Thread.Sleep(Global.Delay); // reduce CPU load
// process flags
if (disconnect)
{
disconnect = false;
state = state.Disconnect();
}
if (connect)
{
connect = false;
state = state.Connect(tempPortName);
}
if (reset)
{
reset = false;
if (state is ResettableState)
{
state = new Identified(port);
}
}
// continue with state-specific actions
if (state is Disconnected)
{
ClearQueue();
Exception innerException = ((Disconnected)state).RemoveInnerException();
// raise events
if (DeviceIdentified != null)
{
DeviceIdentified(null);
}
if ((innerException != null) && (PortClosed != null))
{
PortClosed(innerException);
}
}
else if (state is Connected)
{
ClearQueue();
string connectionInfo;
state = ((Connected)state).Identify(Global.Identification, out connectionInfo);
// raise events
if ((state is Identified) && (DeviceIdentified != null))
{
DeviceIdentified(connectionInfo);
}
}
else if (state is Identified)
{
ClearQueue();
Flush();
state = ((Identified)state).Reset();
// raise events
if (state is Ready)
{
if (DeviceReady != null)
{
DeviceReady();
}
}
}
else if (state is Ready)
{
if (transactionsQueue.Count > 0)
{
lastTransaction = transactionsQueue.Dequeue();
string command = lastTransaction.Command.Command();
if (lastTransaction.ExpectsResponse == Response.ExpectsResponse) // query commands
{
string response;
// Terminate all commands which expect response with a question mark (if not already present). With the exception of compensate commands which expect response but do not have question mark.
if ((lastTransaction.Command.Command().Contains("?") == false) && (lastTransaction.Command != Commands.CompensateOpen) && (lastTransaction.Command != Commands.CompensateShort))
{
command += "?";
}
state = ((Ready)state).Query(command, out response); // query the device
Transaction outputTransaction = new Transaction(lastTransaction.Command, lastTransaction.ExpectsResponse); // make a copy of the transaction to pass out
outputTransaction.AddResponse(response); // add the received response
// raise events
if ((DataUpdated != null) && (state is Ready))
{
DataUpdated(outputTransaction);
}
}
else // send commands
{
if (lastTransaction.Parameter == null) // without parameter
{
state = ((Ready)state).Send(command);
}
else // with parameter
{
state = ((Ready)state).Send(command + " " + lastTransaction.Parameter);
}
}
}
else if (TransactionQueueEmpty != null) // raise event if transaction queue is empty
{
TransactionQueueEmpty();
}
}
}
}