/******************************************************************************
*             Program to use the experimental DAC, ver. beta 2.01             *
*                                                                             *
*                                     by                                      *
*                                                                             *
*             L. Padilla (e-mail: padilla at domain "gae ucm es")             *
*                                                                             *
*                             Madrid, 1995 - 1997                             *
*                                                                             *
* Latest version at http://www.gae.ucm.es/~padilla/extrawork/dac.c            *
******************************************************************************/


#define DPPORT  0x0378     /* Data    parallel port 1. */
#define CPPORT  0x037A     /* Control parallel port 1. */
#define CSPORT  0x03FC     /* Control serial   port 1. */
#define SIZE    1500000uL  /* Bytes to record.         */


#include    <dos.h>
#include   <time.h>
#include  <stdio.h>


main (void)
{
    unsigned char byte, delay;
    register unsigned char i;
    register unsigned long j;

    clock_t time3, time4;

    FILE * file;


    printf ("\n");

    outp (CPPORT, 0xFB);  /* Sets to 0v control pins of parallel
                            port 1 to avoid possible drifts.    */

    outp (CSPORT, 0x00);  /* Sets to around -11v pin number 4 of serial
                            port 1 to feed polarization voltage.       */

    outp (DPPORT, 0x80);  /* Sets initial voltage of DAC (half way). */

    printf ("Enter delay (recommended 74) (0 - 255): ");  /* To match play and
                                                           record times      */
    scanf ("%u", & delay);  /* Waits for enter. */
/*    delay = 74;  /* */

    time3 = clock ();

    file = fopen ("sonido.dat", "rb");  /* In RAM disk (highly recommended) */

    for (j = 0uL; j < SIZE; j++)
    {
        for (i = 0u; i < delay; i++)  /* Delay loop. */
            ;

        fread (& byte, 1, 1, file);  /* Reads data from file. */

        byte = ~ byte;  /* Inverts, setting right value, otherwise
                          only exists a phase difference of 180 deg. */

        outp (DPPORT, byte);  /* Plays digitalization with DAC,
                                but speed will be incorrect.   */

/*        printf ("%2.2X\n", byte); /* Prints digitalized value (hex). */
/*        printf ("%u %u\n", j, byte); /* Prints digitalized value (dec). */
    }

    time4 = clock ();

    fclose (file);

    outp (DPPORT, 0x00);  /* Sets to 0v the 8 data pins
                            of parallel port 1.        */

    printf ("Time of play: %lf\n", (float) (time4 - time3)/(float) CLK_TCK);
    printf ("\n");


    return 0;
}