/****************************************************************************
 *  This sample will prompt the user for a voltage between 0 and 10 volts,  *
 *  then calculate the actual voltage based on the resolution of the DAC and*
 *  output the voltage to the desired DAC channel. The program also uses the*
 *  calibration values stored in the eeprom in calculating the output       *
 ****************************************************************************/
#include <stdio.h>
#include <dos.h>
#include <conio.h>
#include "commdrv.h"

unsigned int a = 0,b = 0;

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;
      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 */

void ReadCal(unsigned int Address,unsigned int channel)
{
  char MSG[255]="\0";
  char temp[255]="\0";
  int i = 0;
  sprintf(temp, "CAL%X?", channel);  // read the point configuration
  writePod(Address, temp);
  readPod(Address,MSG);
  sscanf(&MSG[21], "%04X", &a);   //values for +/-5V at end of array
  sscanf(&MSG[26], "%04X", &b);   //a=zero offset, b=span offset

  delay(100);
}

double Cal(int data)
{
  double value = 0.0;
  a>>=4;             //need to shift values down one nybble for this math
  b>>=4;
  value = (((4095.0 - b- a) / 4095.0) * data + a);
  return value; //returns calibrated counts
}//end cal

/****************************************************************************
 *  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)
{
char            ch;
float           voltsentered,voltsexpected;
unsigned        temp,dacnum;
char            MyStr[255];
char            MyStr2[255];
int             counts=0;

/* prompt for the DAC number and desire voltage. */

do{
   gotoxy (1,3);
   clreol();
   printf("Enter the DAC number (0 through 7 only): ");
   ch=getche();
   dacnum=ch-'0';         /* using ascii code to get dac_number*/
}while ((dacnum < 0) || (dacnum > 7));

do{
   gotoxy (1,7);
   clreol();
   puts("Card configured for +/-5V range");
   printf("Enter a voltage between -5.000V and 4.997V: ");
   scanf("%f",&voltsentered);
}while ((voltsentered<-5.000) || (voltsentered>4.997));
   voltsentered = (voltsentered / 0.002441);

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

counts=(int) voltsentered;
voltsexpected = (float) counts * 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.",voltsexpected);

sprintf(MyStr2, "AC%x=0000,00,00,00,0000",dacnum);//setup for +/-5V
writePod(Address, MyStr2);
readPod(Address, MyStr2);
delay(100);
ReadCal(Address,dacnum);            //get calibration coefficients from card
counts+=2047;                   //can only write positive counts to card
counts = Cal(counts);
sprintf(MyStr, "A%x=%03x0", dacnum,counts);
writePod(Address, MyStr);
readPod(Address, MyStr);

} /* end write_DAC */

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

clrscr();
printf(
"                        C SAMPLE #1: SAMPLE1.C                          \n\n"
"  This sample will prompt the user for a voltage between -5V and 4.997V,  \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"
"  Board Configuration:                                                  \n\n"
"      -- The Base Address of the COM card should be set to the address    \n"
"         that will be entered during program execution.                   \n"
"      -- All remaining jumper settings are irrelevant                   \n\n");

//check on other configuration information

Address=AskForBaseAddress(0x300);
initCommCard(Address, 9600);
clrscr();
do
{
  write_DAC(Address);
  printf("\n\n\nWould you like to output another value (Y or N)? ");
  key = getch();
  clrscr();
}while((key != 'N') && (key != 'n'));
clrscr();
} /* end main */