#include <stdio.h>
#include <ctype.h>
#include <dos.h>
#include <conio.h>
#include <string.h>

unsigned int BASE= 0x300;

/***************************************************************************
 * FUNCTION: AskForBaseAddress                                             *
 * PURPOSE: Prompt user to enter base address for their I/O card.          *
 **************************************************************************/
unsigned AskForBaseAddress(unsigned int OldOne)
{
	char msg[7];
	int NewOne = 0, Success = 0, Dummy;
	int AddrInputPosX, AddrInputPosY;

	puts("\nPlease enter the Base Address OF THE DAC 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 main()
	{
		char key_entered;
		double val=0.0;
		unsigned counts=0;
    BASE=AskForBaseAddress(BASE);
		do
		{
			printf("Base Address %04x, DACs at +C and +E\n",BASE);
			printf("Press `1234567890 to output %% to the DACs\n");
			puts("`= zero percent, 1=10%, 9=90%, 0=100%, etc.");
			puts("Press N to exit");
			key_entered = getch();
			clrscr();
			if (key_entered=='`')
			{
			val=0.0;
			}
			else
			if (key_entered == '0')
			{
				val=1.0;
			}
			else
			if (isdigit(key_entered))
			{
				val=0.1*(key_entered-'0');
			}
			else continue;

			counts=(4095.0*val);
			outport(BASE+0x0C,counts);
			outport(BASE+0x0E,4095-counts);
			printf("Wrote %04x to Base+C, and %04x to Base+E\n",counts,4095-counts);
		} while (key_entered != 27);
	}