/* Data acquisition program for two microphones and a speaker.
   Rich Kozick, Spring 1997 */

#include "brtenv.h"              /* basic real-time environment */
#include "math.h"

#define TS         1e-4          /* Sample spacing */
#define TMR0       0             /* Use timer0 for exec-time trace */
#define PER        1e4           /* Pulse period (samples) */
#define DUR        1e2           /* Pulse duration (samples) */
#define PFREQ      500           /* Sinusoid frequency, in hertz */

float mic1, mic2, out, freq;
long per_cnt=0, pulse_flag=0, dur_cnt=0;

float exec_time;                     /* execution time */
unsigned long count0;                /* timer0 time count */

/* error flag for CHKERR31 at last dual-port memory location */
int *error = (int *) (DP_MEM_BASE + DP_MEM_SIZE - 1);


/* timer0 interrupt service routine */
isr_t0()
{
  register int i;		/* Counter */

  begin_isr_t0(*error);         /* delete if overload check not needed */
  service_trace();              /* call TRACE service routine */
  count0 = count_timer(TMR0);   /* get current time count of timer0 */

  ds1102_ad_start();            /* start DS1102 ADCs */

  mic1 = ds1102_ad(1);          /* read input from ADC channel 1 */
  mic2 = ds1102_ad(2);          /* read input from ADC channel 2 */

  if (++per_cnt == PER)
  {
    pulse_flag = 1;
    dur_cnt = 0;
    per_cnt = 0;
  }
  if (pulse_flag)
  {
    if (++dur_cnt <= DUR)
      out = 0.1*sin(freq*dur_cnt);
    else
    {
      pulse_flag = 0;
      out = 0;
    }
  }
  else
    out = 0;

  ds1102_da(1, out);            /* write output to DAC channel 1 */

  exec_time = time_elapsed(TMR0, count0); /* get execution-time */
  end_isr_t0();                 /* delete if overload check not needed */
}


main()
{
  register int i;

  init();                        /* init DAC mode, calibrate ADCs */
  *error = NO_ERROR;             /* initialize overload error flag */
  dp_mem[0].f = 0.0;             /* init 1st dp-mem loc for type float */
  start_isr_t0(TS);              /* initialize sampling clock timer */

  freq = 2*3.14159*PFREQ*TS;
  while (*error == NO_ERROR);    /* background process */

  ds1102_da(1, 0.0);             /* on error clear DAC channel 1 */
}