CCommSerial

CCommSerial is a C++ class that is provided to simplify 825 serial communications. CCommSerial is inherited from the CComm base class.

Constructors

CCommSerial(void)
CCommSerial(int port);

These constructors just create a CCommSerial object without opening a communications channel.

Parameters

• port - serial port number ( 1 = COM1, 2 = COM2 )

Remarks

For the 825gen2 support is added for USB serial adapters and sending text to USB printers. Offsets for the COM port are defined for these devices: COMM_USB_SERIAL_OFFSET, and COMM_USB_PRINTER_OFFSET.

Examples

CCommSerial *pSerial = new CCommSerial();
// Creates a CCommSerial instance that does not have a port specified yet. Method SetPort() must be called before calling Open().

CCommSerial *pSerial = new CCommSerial(2);
// Creates a CCommSerial instance that when opened will connect to COM2

USB to Serial adapter example 825gen2

CCommSerial *pSerial = new CCommSerial(COMM_USB_SERIAL_OFFSET);
// Creates a CCommSerial instance that when opened will connect to first USB to serial adapter /dev/ttyUSB0

USB Printer example 825gen2

CCommSerial *pSerial = new CCommSerial(COMM_USB_PRINTER_OFFSET + 1);
// Creates a CCommSerial instance that when opened will connect to second USB printer /dev/usb/lp1

NOTE When "new" is used to instantiate an object be sure to "delete" the memory when the use of the object is complete. Otherwise a memory leak will occur and the 825 may run out of memory.

  pSerial->Close();
  delete pSerial;
  pSerial = NULL; // Good practice to set pointer to NULL after delete

Example

   if(commTypeSelection == SERIAL)
   {
      int commPort = 2;
      CCommSerial *pSerial = new CCommSerial(commPort);
      pComm = pSerial;
   }
   pComm->Open();

   // Now the app can call pComm->Send to send data without regard for whether it is serial or TCP/IP.

   pComm->AddRcvEvent(CHR_STX, CHR_ETX, CommEventDataMsg, 0, NULL);

}

void StopCommunications(void)
{ 
   if(pComm != NULL)
   {
       pComm->Close();
       delete pComm;
       pComm = NULL;
   }
}

COMM_EVENT(DataMsg)
{
   uint8* buf = pConnection->GetRcvBuffer();
   buf[pConnection->GetRcvPos() - 1] = '\0';

   printf("rcvd [%s]\r\n", buf);

   if(buf[1] == 'T') // Received <STX>T<ETX> return timeval
   {
       time_t tmval;
       time(&tmval);  // Get timeval

       char response[12];
       sprintf(response, "%d\n", tmval);
       // pConnection isn't important in the case of serial port, but if TCP/IP server it is important to send
       // the response to the connection that the message was received from.
       pComm->Send(pConnection, response, strlen(response);
    }


   return 0;
}

Member Functions

SetPort

Sets the communications port to be used when Open() is called.

void SetPort(int port);

Parameters

• port - the port number

Return Value

Function does not return any parameters

Open

Opens the previously specified port.

int Open(void);

Parameters

• void - no parameters

Return Value

Returns 1 if successful or 0 if unsuccessful.

Remarks

Example

Close

Closes the connection

int Close(void);

Parameters

Function does not accept any parameters

Return Value

Function always returns zero.

Remarks

For serial ports it may be necessary to provide some delay to allow all of the buffered data to be sent out of the port before closing the port.

Example

SetParameters

Set the baud rate, number of data bits, parity, and number of stop bits for serial ports.

bool SetParameters(baud_index baud, data_bit_index = data8, parity_index = parityNone, stop_bit_index = stopOne);

Parameters

• baud_index - baud1200, baud2400, baud4800, baud9600, baud19200, baud38400, baud57600, or baud115200
• data_bit_index - data7 or data8
• parity_index - parityNone, parityEven, or parityOdd
• stop_bit_index - stopOne or stopTwo

Return Value

Returns true if successful, false if not successful.

Remarks

Examples

CCommSerial* pSerial = new CCommSerial(2);
if(pSerial->Open())
{
   pSerial->SetParameters(CCommSerial::baud9600, CCommSerial::data7, CCommSerial::parityEven, CCommSerial::stopOne);
}

CCommSerial* pSerial = new CCommSerial(2);
if(pSerial->Open())
{
   pSerial->SetParameters(CCommSerial::baud19200);
}

IsReady

Check the state of the serial CTS input (for serial ports that are equipped with CTS input)

bool IsReady(void);

Parameters

Function does not accept any parameters.

Return Value

Function returns true if CTS is active, false if CTS is inactive.

Remarks

IsReady() will return false if the CTS line is unconnected. Printers or other devices must be wired correctly for applications to be able to use this function to determine their readiness. The main board COM3 is not currently supported by this function.

Example

CCommSerial *pSerial = new CCommSerial(2);
if(pSerial->Open())
{
   pSerial->SetRTS(true);
   if(pSerial->IsReady() == false)
   {
      DisplayText(0, 0, "Device offline, or disconnected");
   }
}

SetRTS

Set the state of the serial RTS output

bool SetRTS(bool bRTSOn = true);

Parameters

• bRTSOn - true to turn on RTS output, false to turn off RTS output

Return Value

Returns true if successfully set RTS state, false otherwise.

Remarks

Example

CCommSerial* pSerial = new CCommSerial(2);
if(pSerial->Open())
{
   pSerial->SetRTS(true);
}

See Also

• CComm
• CCommClient
• CCommServer