Subj : Re: serial comm?
To   : borland.public.cpp.borlandcpp
From : "Paul Wearne" <paul.wearne@blueyonder.co.uk>
Date : Fri Mar 05 2004 01:45 pm

The attached files might help.

I use the PC's serial port to simulate the serial port of an
Microcontroller, therefore the file names may seem a bit confusing.

It does Rx and Tx with no hardware handshaking. The received data is
buffered by windows.

Hope this helps.

/***************************************************************************
*
 *
 * FILENAME: $Workfile:$
 *
 * DESCRIPTION:
 *

****************************************************************************
 * CHANGE HISTORY: PVCS automatically inserts check in information.

****************************************************************************
 * $Log:$

***************************************************************************/

/* LIBRARY INCLUDE FILES */
#include <windows.h>
#include <stdio.h>

/* PROJECT INCLUDE FILES */
#include "sci0.h"

/* LOCAL SYMBOLIC CONSTANTS */

/* LOCAL MACROS DEFINITIONS */

/* LOCAL ENUM DEFINITIONS */

/* LOCAL STRUCT DEFINITIONS */

/* LOCAL TYPE DEFINITIONS */

/* GLOBAL VARIABLE DECLARATIONS */

/* LOCAL VARIABLE DECLARATIONS */
static HANDLE     h_comm = NULL;
static OVERLAPPED overlapped;

/* LOCAL FUNCTION PROTOTYPES */

/* FUNCTION DEFINITIONS */

/***************************************************************************
*
 * FUNCTION: SCI0_Initialise
 * DESCRIPTION:
 *  Configures the SCI peripheral device for asynchronous serial
 *  communications. The SCI shall be configured at the specified baud rate,
 *  with 8 bits, 1 stop bit and no parity.
 * Parameters list:-
 *  U16 baud. This is the asynchronous baud rate, typical values are:-
 *       110, 300, 600, 1200, 2400, 4800, 9600, 14400, 19200, 38400
 * Return Value
 *  BOOL If TRUE the SCI has been successfully configured.
 *       IF FALSE the SCI could not be configured.
 *

****************************************************************************
 * Modification History

****************************************************************************
 *    Initial Implementation

***************************************************************************/
BOOL SCI0_Initialise(U16 baud)
{
  DCB          dcb;
  COMMTIMEOUTS timeouts;
  CHAR         dcb_string[20];

  if (h_comm !=NULL)
  {
    CloseHandle(h_comm);
  }

  for (;;)
  {
    /* Open the comm port */
    h_comm = CreateFile( "COM1", GENERIC_WRITE | GENERIC_READ, 0,
                         0, OPEN_EXISTING,
                         FILE_FLAG_OVERLAPPED | FILE_FLAG_WRITE_THROUGH,
                         NULL );

    /* Check its OK */
    if (h_comm == INVALID_HANDLE_VALUE)
    {
      /* we are getting access denied, */
      /* dwError = GetLastError(); */

    }
    else
    {
      break;
    }
  }

  /* Setup parameters */
  FillMemory(&dcb, sizeof(dcb), 0);
  dcb.DCBlength = sizeof(dcb);

  sprintf(dcb_string, "%u,n,8,1", baud);
  BuildCommDCB(dcb_string, &dcb);

  /* Check setup OK */
  if (SetCommState(h_comm, &dcb))
  {
    timeouts.ReadIntervalTimeout         = MAXDWORD;
    timeouts.ReadTotalTimeoutConstant    = 0;
    timeouts.ReadTotalTimeoutMultiplier  = 0;
    timeouts.WriteTotalTimeoutConstant   = 0;
    timeouts.WriteTotalTimeoutMultiplier = 0;

    SetCommTimeouts (h_comm, &timeouts);
    SetupComm( h_comm, 1600, 1600 );
    (void) memset( &overlapped, 0, sizeof(overlapped) );
  }

  return TRUE;
}

/***************************************************************************
*
 * FUNCTION: SCI0_Read
 * DESCRIPTION:
 *  Reads up to in_buffer_length bytes into the supplied in_buffer_ptr,
 *  providing there is data in the SCI's peripheral receive buffer.
 *  If in_buffer_ptr is null no data is placed in in_buffer_ptr. The SCI's
 *  buffer is still emptied and the number of bytes emptied is return.
 * Parameters list:-
 *  U8* in_buffer_ptr. Buffer in which the received data should be placed.
 *  U16 in_buffer_length. The size of in_buffer_ptr.
 * Return Value
 *  U16 Returns the number of bytes placed into the in_buffer_ptr.
 *

****************************************************************************
 * Modification History

****************************************************************************
 *    Initial Implementation

***************************************************************************/

U16 SCI0_Read(U8* in_buffer_ptr, U16 in_buffer_length)
{
  U16 bytes_read = 0;
  U32 num_bytes_read = 0;

  if ( ReadFile(h_comm, in_buffer_ptr, in_buffer_length, &num_bytes_read,
&overlapped ) )
  {
    bytes_read = (U16) num_bytes_read;
  }

  return(bytes_read);
}

/***************************************************************************
*
 * FUNCTION: SCI0_Write
 * DESCRIPTION:
 *  Writes the contents of buffer specified by out_buffer_ptr into the SCI's
 *  peripheral transmit buffer. If the SCI's transmit buffer is full it
 *  shall wait until the SCI has emptied the buffer before continuing to
load
 *  the transmit buffer.
 * Parameters list:-
 *  const U8* out_buffer_ptr. Buffer which contains the data for
transmission.
 *  U16       out_buffer_length. Number of elements in the out_buffer_ptr
              which require transmission.
 * Return Value
 *   none
 *

****************************************************************************
 * Modification History

****************************************************************************
 *    Initial Implementation

***************************************************************************/
void SCI0_Write(const U8* out_buffer_ptr, U16 out_buffer_length)
{
  U16 buf_idx;
  U32 num_bytes_written;

  WriteFile (h_comm, out_buffer_ptr, out_buffer_length, &num_bytes_written,
&overlapped);
}

/* EOF */

"ge" <e_c_l_e_s@a-znet.com> wrote in message
news:qaug401qa301loo6o6gs2fh1f67ms00v03@4ax.com...
> using Borland C++ 5.0 (I have 5.5, too, but not installed)
> Win NT4
>
> I need to do some simple serial I/O (COM1) in a win32 console.  I've
> looked around, and what I've found so far is confusing.  If there is
> some "all you have to do is ..." URL, I'd appreciate a pointer to it.
>
> TIA,
> George

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