/****************************************************************************
*                        C SAMPLE #1: SAMPLE1.C                            *
*                                                                          *
*  This sample will prompt the user for a voltage between 0 and 10 volts,  *
*  then calculate the actual voltage based on the resulution of the DAC and*
*  output the voltage to the desired DAC channel.                          *
*                                                                          *
****************************************************************************/
#include <stdio.h>
#include <dos.h>
#include <conio.h>

unsigned AskForBaseAddress(unsigned int OldOne)
{  char msg[7];
   int NewOne = 0, Success = 0, Dummy;
   int AddrInputPosX, AddrInputPosY;

   puts("\nPlease enter the Base Address for your card (in hex)");
   printf("or press ENTER for %X.\n>", OldOne);
   AddrInputPosX = wherex(); AddrInputPosY = wherey();
   do {
     gotoxy(AddrInputPosX, AddrInputPosY);
     clreol();
     msg[0] = 5; msg[1] = 0;  //just setting up cgets
     cgets(msg);
     sscanf(msg + 2, "%x", &NewOne);
     Success = 1;
     Dummy = NewOne;
	   if (msg[1] == 0) {
       gotoxy(AddrInputPosX, AddrInputPosY);
       printf("%X", OldOne);
       Success = 1;
       Dummy = OldOne;
     }
   } while(!Success);
   return (Dummy);
} // end of AskForBaseAddress

/****************************************************************************
*  FUNCTION: write_DAC() - local routine                                   *
*                                                                          *
*   PURPOSE: Prompts the user for DAC number and voltage, then calculates  *
*            the actual output voltage based on resolution, displays it    *
*            and writes the value to the DAC.                              *
****************************************************************************/
void write_DAC(unsigned int Address)
{
  float           volt_value_entered=0.0,volt_value_expected=0.0;
  unsigned        counts_entered,temp,dac_number;
  unsigned char   lo_byte,hi_byte;
  char            ch;

// prompt for the DAC number and desired voltage.

  do {
     gotoxy (1,2);
     clreol();
     printf("Enter the DAC number you wish to output to (0 - 7 only): ");
     ch=getche();
     dac_number=ch-'0';         //using ascii code to get dac_number
  } while (((int)dac_number < 0) || ((int)dac_number > 7));
  do {
    gotoxy (1,7);
    printf("If your card is not set for 0-10V DAC outputs, the value will be proportional.");
    printf("Enter a voltage between 0.000v to 9.997v: ");
    clreol();
    scanf("%f",&volt_value_entered);
  } while ((volt_value_entered<0.000) || (volt_value_entered>9.997));

// compute the digital output needed for this value and the actual voltage
//   that will be expected, and display the voltage.

  counts_entered=(int)( volt_value_entered/0.002441);
  volt_value_expected = (float) counts_entered * 0.002441;
  printf("\n\n\nDue to the 12-bit resolution of the DAC, you should expect\n");
  printf("to see a voltage of %4.3f.",volt_value_expected);

// write the count value out to the DAC
  outport(Address + (2 * dac_number),counts_entered);
} // end write_DAC


/****************************************************************************
*  FUNCTION: main() - local routine                                        *
****************************************************************************/
void main()
{
  int key_entered;
  unsigned int Address;

  clrscr();
  printf(
   "                        C SAMPLE #1: SAMPLE1.C                            \n"
   "                                                                          \n"
   "  This sample will prompt the user for a voltage between 0 and 10 volts,  \n"
   "  then calculate the actual voltage based on the resolution of the DAC and\n"
   "  output the voltage to the desired DAC channel.                          \n"
   "                                                                          \n");
  Address=AskForBaseAddress(0x300);
  clrscr();
//clear voltage restrict -- this allows the DAC reference to be non-zero
  outportb(Address+0x10,0x40);

  printf(
   "\n\n\n  Board Configuration:\n\n"
   "  -- Base address is %x hex.\n"
   "  -- DACs should be placed in the 10V unipolar mode.\n"
   "     -- if the DACs are in any other mode, the \n"
   "        values will be proportionally incorrect\n"
   "\n\n\n\nPress any key to continue", Address);
   getch();

  do
     {
     clrscr();
     write_DAC(Address);
     printf("\n\n\nWould you like to output another value (Y or N)? ");
     key_entered = getch();
     }
  while((key_entered != 'N') && (key_entered != 'n'));
  clrscr();
} /* end main */