public byte[] getDataToSend()
{
byte[] bufferToSend = null;
if (RequestState == eRequestState.eSENDING_NAK)
{
bufferToSend = new byte[1];
bufferToSend[0] = NAK;
RequestState = eRequestState.eNAK_SENT;
}
else if (RequestState == eRequestState.eSENDING_ANSWER)
{
bufferToSend = new byte[1 + 1 + 1 + MessageToSend.Length + 1];
bufferToSend[0] = STX;
bufferToSend[1] = MessageToSend.Opcode;
bufferToSend[2] = MessageToSend.Length;
if (MessageToSend.Length > 0)
{
Buffer.BlockCopy(MessageToSend.Msg, 0, bufferToSend, 3, MessageToSend.Length);
}
bufferToSend[MessageToSend.Length + 3] = MessageToSend.chks();
RequestTimer.Start();
RequestTimer.Restart();
RequestState = eRequestState.eANSWER_SENT;
}
else if (RequestState == eRequestState.eSENDING_REQUEST)
{
bufferToSend = new byte[1 + 1 + 1 + MessageToSend.Length + 1];
bufferToSend[0] = STX;
bufferToSend[1] = MessageToSend.Opcode;
bufferToSend[2] = MessageToSend.Length;
if (MessageToSend.Length > 0)
{
Buffer.BlockCopy(MessageToSend.Msg, 0, bufferToSend, 3, MessageToSend.Length);
}
bufferToSend[MessageToSend.Length + 3] = MessageToSend.chks();
RequestTimer.Start();
RequestTimer.Restart();
RequestState = eRequestState.eREQUEST_SENT;
}
return(bufferToSend);
}
public void messagePoll(int data)
{
switch (MessageState)
{
default:
case eMessageState.eSTX:
{
if (data >= 0)
{
if ((byte)data == STX)
{
MessageState = eMessageState.eOPCODE;
MessageTimer.Restart();
}
else if ((byte)data == NAK)
{
MessageState = eMessageState.eNAK_RECEIVED;
MessageTimer.Restart();
}
}
break;
}
case eMessageState.eOPCODE:
{
if (data >= 0)
{
ReceivedMessage.Opcode = (byte)data;
MessageTimer.Restart();
MessageState = eMessageState.eLENGTH;
}
else if (MessageTimer.ElapsedMilliseconds > Timeout)
{
MessageState = eMessageState.eSTX;
}
break;
}
case eMessageState.eLENGTH:
{
if (data >= 0)
{
ReceivedMessage.Length = (byte)data;
MessageTimer.Restart();
if (ReceivedMessage.Length > 0)
{
MessageReceivedBytes = 0;
MessageState = eMessageState.eMSG;
}
else
{
MessageState = eMessageState.eCHKS;
}
}
else if (MessageTimer.ElapsedMilliseconds > Timeout)
{
MessageState = eMessageState.eSTX;
}
break;
}
case eMessageState.eMSG:
{
if (data >= 0)
{
ReceivedMessage.Msg[MessageReceivedBytes] = (byte)data;
MessageReceivedBytes++;
MessageTimer.Restart();
if (MessageReceivedBytes == ReceivedMessage.Length)
{
MessageState = eMessageState.eCHKS;
}
else if (MessageReceivedBytes > ReceivedMessage.Length)
{
MessageState = eMessageState.eSTX;
}
}
else if (MessageTimer.ElapsedMilliseconds > Timeout)
{
MessageState = eMessageState.eSTX;
}
break;
}
case eMessageState.eCHKS:
{
if (data >= 0)
{
MessageTimer.Restart();
if ((byte)data == ReceivedMessage.chks())
{
MessageState = eMessageState.eNEW_MSG;
}
else
{
MessageState = eMessageState.eNAK_TO_SEND;
}
}
else if (MessageTimer.ElapsedMilliseconds > Timeout)
{
MessageState = eMessageState.eSTX;
}
break;
}
case eMessageState.eNEW_MSG:
case eMessageState.eNAK_RECEIVED:
case eMessageState.eNAK_TO_SEND:
{
break;
}
}
}