/* This example demonstrates the use of some
 * NI-VXI Word Serial functions.  Word Serial functions
 * provide a method for communicating with message based
 * VXI instruments.  
 * The function Word Serial Write - WSwrt() - allows
 * the user to send a message to an instrument.  The function
 * Word Serial Read - WSrd() - allows the user to read a 
 * response back from the instrument.  Refer to Chapter
 * Four entitled Commander Word Serial Protocol Functions
 * of the NI-VXI Function Reference Manual for a detailed
 * description of these functions.
 */


#include "nivxi.h"
#include <stdio.h>
#include <conio.h>


main()
{
  
  INT16 logical_address = 0;         /* the logical address of the device*/
  char send_buffer[6] = "*idn?";    /* the command we will send */
  UINT32 send_count = 5;             /* max number of bytes to send*/
  UINT16 mode = 3;                   /* mode of transfer */
  
                                
  /*
   *        mode is a value ranging from 0 to three.  It is
   *        a bit vector consisting of two bits.
   *        When bit 0 == 0 abort the transfer if the device is not DIR
   *                   == 1 poll until the device is DIR.
   *
   *        When bit 1 == 0 set the END bit at the end of transfer
   *                   == 1 clear END bit at end of transfer
   *
   *        In this example, we'll use mode == 3: keep polling until
   *        the device is ready, and set the END bit when we're done.
   *     
   */
  
  UINT32 ret_count;         /* the number of bytes actually sent */
  INT16 ret;                /* return status vector (error codes) */
  
  UINT8 rec_buffer[1024];       /* buffer for data returned from instrument */

  
  printf("\nYou can run this example with VICtext.  If it is not already running,");
  printf("\nyou can quit this program, launch VICtext, then run this program again.");
  printf("\nBefore sending *idn?, run the ws.log script file in VICtext by typing");
  printf("\n'$ <path>\\ws.log' at the prompt.  This will allow VICtext to act like");
  printf("\na message based device that we can communicate with.  VICtext");
  printf("\nwill then wait for the wswrt command, which you can send from the");
  printf("this example program by pressing any key when prompted.");

  ret = InitVXIlibrary();		/* Always open the VXI library
                                 * at the beginning*/
  
  if (ret < 0)                  /* check for errors */
    {
      /* If we get here, there was an error opening the library. */
      return -1;
  }
  

  printf("\nPress a Key to send the string '*idn?'");
  while (!kbhit());
  _getch();	

  /* Send the command '*idn?' to logical address 0. */

  ret = WSwrt(logical_address, send_buffer, send_count, mode, &ret_count);
  
  if (ret & 0x8000) /* check bit 15 to see if an error occured */
    {
      /* If we get here, WSwrt encountered an error. 
       * Close and exit the program */
      printf("\nWord Serial Write did not succeed!");
      CloseVXIlibrary();
	  return -1;
    }
	
  printf("\nPress a Key to read response");
  while (!kbhit());
  _getch();							/* Clear input buffer */

  /* Read the response back from logical address 0 */
  
  send_count = 1024;                  /* read up to 1024 bytes */
  mode = 1;

  /*       With Word Serial Read, the definition of mode changes somewhat. 
   *       mode is 15 bit bit vector now.
   *       Refer to the software reference manual for the function of each bit 
   *       position.  In this example, we'll use mode == 1, which tells 
   *       us to poll the target instrument until it is ready to send
   *       data, and terminate the transfer when the end bit is set.
   */

  printf("\nSending %s to the instrument\n", send_buffer);

  ret = WSrd(logical_address, rec_buffer, send_count, mode, &ret_count);
  
  if (ret & 0x8000) /* check bit 15 to see if an error occured */
    {
      /* If we get here, WSrd encountered an error. 
       * Close and exit the program */
      
      CloseVXIlibrary();
      return -1;
    }

  printf("Response from instrument:\n   %s\n", rec_buffer);
  
  ret = CloseVXIlibrary();
  
  printf("\nPress any key to exit...");
  while (!kbhit());

}