// clear the serial buffer
public void flushSerialBuffer(SerialBuffer serialport)
{
serialport.Clear();
}
// processData. processData assembles the frames and calls to transitionAction
public void processData(SerialBuffer sBuffer)
{
int i;
int numBytesToRead = sBuffer.bytesAvailable(); // let's see what we 've got...
do
{
if (remainingBytes == 0) // previous frame was fully read
{
if (numBytesToRead >= 6) // nead at least 6 bytes to read frame header
// get the first 6 bytes (starter(1)+sender-receiverid(2)+frame type(1)+payload length (2))
// reading first 6 bytes into FrameHead
{
sBuffer.readBytes(FrameHead, 6);
// now cheking for framestarter character mismatch
if (FrameHead[0] != framestarter)
{
flushSerialBuffer(sBuffer);
}
else // reamaining bytes should be the payload length plus the terminator and two CRC bytes
{
remainingBytes = FrameHead[4] + FrameHead[5] * 256 + 3;
}
}
}
else if (numBytesToRead >= remainingBytes)
{ // it's time to get the remaining frame(s)
int totalBytes = remainingBytes + 6; // calculate total length
byte[] buffer = new byte[totalBytes];
byte[] remBuffer = new byte[remainingBytes];
// now reading remaining bytes as estimated using the frame header
// going altogether
sBuffer.readBytes(remBuffer, remainingBytes);
// tailoring bufhead and rembuffer into buffer
for (i = 0; i < totalBytes; i++)
{
if (i < 6)
{
buffer[i] = FrameHead[i];
}
else
{
buffer[i] = remBuffer[i - 6];
}
}
// now handling the message...
// checking terminator and CRC
ushort CRC = (ushort)(buffer[totalBytes - 2] + 256 * buffer[totalBytes - 1]);
if ((buffer[totalBytes - 3] == frameterminator) && (checkCRC(buffer, totalBytes - 2, CRC)))
{
EZFrame frame = bytes2Frame(buffer);
// done
if (frame.ReceiverID == NodeID) // packet addressed to this node
{
transitionAction(frame); // change internal state and act
}
}
// clearing remaining bytes
remainingBytes = 0;
}
numBytesToRead = sBuffer.bytesAvailable();
} while ((numBytesToRead >= remainingBytes) && (remainingBytes > 0));
}
// Constructor
public EZRoboNetDevice(byte node_id, byte node_type)
{
NodeID = node_id;
DevNodeType = node_type;
// initializing the CommPort and CommPortBuffer
CommPortBuffer = new SerialBuffer();
CommPort = new System.IO.Ports.SerialPort("COM1");
CommPort.BaudRate = 19200;
CommPort.WriteBufferSize = 10000;
CommPort.ReadBufferSize = 10000;
CommPort.Parity = System.IO.Ports.Parity.None;
CommPort.Handshake = System.IO.Ports.Handshake.None;
CommPort.StopBits = System.IO.Ports.StopBits.One;
CommPort.ReceivedBytesThreshold = 2;
CommPort.DataReceived += this.SerialDataReceived;
// Initializing the Timer
SyncTimer = new System.Windows.Forms.Timer(); // 10 msec interval
SyncTimer.Interval = 30; // 10 msec interval
SyncTimer.Tick += SyncTimerTick;
// initializing state
state = stIdle;
// flags
PacketSendTimeout = false;
PacketReceiveTimeout = false;
PacketQueueOverflow = false;
// incoming data processing globals
remainingBytes = 0;
FrameHead = new byte[6];
// initializing array of incomplete packets
IncompletePackets = new EZStationPacketFSM[MAX_RECEIVED_PACKETS_NUM];
// null-ing all entries
int i;
for (i = 0; i < MAX_RECEIVED_PACKETS_NUM; i++)
{
IncompletePackets[i] = null;
}
IncompletePacketsNum = 0;
// initializing array of received packets
ReceivedPackets = new EZPacket[MAX_RECEIVED_PACKETS_NUM];
ReceivedPacketsNum = 0;
// initializing array of outbound packets
OutboundPackets = new EZPacket[MAX_OUTBOUND_PACKETS_NUM];
OutboundPacketsNum = 0;
// initializing entity list. No entities registered yet
EntityList = new RoboEntity[MAX_ENTITY_NUM];
for (i = 0; i < MAX_ENTITY_NUM; i++)
{
EntityList[i] = null;
}
EntityNum = 0;
// starting the NetDevice (opening serial port and starting timer)
CommPort.Open();
SyncTimer.Start();
}
