#include "project.h"

#define PRESSURE      GPIO0
#define PRESSURE_PORT     GPIOA
#define PRESSURE_CHANNEL  ADC_CHANNEL0
#define VREF_CHANNEL ADC_CHANNEL17

#define N_SAMPLES 1000

#define T do { printf("%s:%d\r\n",__FILE__,__LINE__); } while (0)

static int pressure;

struct avg {
	int acc;
	unsigned n;
};

static void avg_reset(struct avg *a)
{
a->acc=0;
a->n=0;
return;
}
static void avg_add(struct avg *a, int v)
{
a->acc+=v;
a->n++;
}
inline static unsigned avg_n(struct avg *a)
{
return a->n;
}

static int avg_get(struct avg *a)
{
if (!a->n) return 0;
return (a->acc) / (a->n);
}


uint16_t pressure_ch (void)
{
  return pressure;
}


static void pressure_calculate (int v,int r)
{
  /* r is 1.25 volts, transducer is 0.5V -> 0 psi 4.5V -> 100psi  */
  /* 100psi is 6.8947573 bar, and we want 256ths of bar */


  if (!r) {
    pressure = 0;
    //  return;
  } else {
    pressure = ((v * 552) / r) - 221;

    if (pressure < 0) pressure = 0;
  }

  printf ("QP: %d %d %d\r\n", v, r, (pressure * 100) / 256);
}



void pressure_tick(void)
{
static unsigned state;
static unsigned backoff=MS_TO_TICKS(1000);
static unsigned timeout;

static struct avg vref_avg;
static struct avg pressure_avg;


timeout++;

if (backoff) {
	backoff--;
	return;
}


switch (state) {
case 0:
  adc_off (ADC1);
  adc_power_on (ADC1);
  backoff=MS_TO_TICKS(5);
  state++;
  break;
case 1:
  ADC_CR2 (ADC1) |= ADC_CR2_RSTCAL;
  backoff=MS_TO_TICKS(2);
  state++;
  break;
case 2:
  if (ADC_CR2(ADC1) & ADC_CR2_CAL)
	state=0;
  ADC_CR2 (ADC1) |= ADC_CR2_CAL;
  backoff=MS_TO_TICKS(2);
  state++;
  break;
case 3:
  if (ADC_CR2(ADC1) & ADC_CR2_CAL)
	state=0;
  state++;

  avg_reset(&vref_avg);
  avg_reset(&pressure_avg);
  break;
case 4:
  if (adc_convert_start(VREF_CHANNEL))
	state=0;
  else {
  timeout=0;
  state++;
  }
  break;
case 5:
  if (adc_convert_done()) {
  avg_add(&vref_avg,adc_convert_get());
  state++;
  } else if (timeout > MS_TO_TICKS(5)) 
	state=0;
  break;
case 6:
  if (adc_convert_start(PRESSURE_CHANNEL))
	state=0;
  else {
  timeout=0;
  state++;
  }
  break;
case 7:
  if (adc_convert_done()) {
  avg_add(&pressure_avg,adc_convert_get());

  if (avg_n(&pressure_avg)<N_SAMPLES)
	state=4;
  else
	state++;
  } else if (timeout > MS_TO_TICKS(5)) 
	state=0;
  break;
case 8:
  pressure_calculate(avg_get(&pressure_avg),avg_get(&vref_avg));
  state=0;
  break;
}

}



void pressure_init (void)
{
  MAP_ANALOG (PRESSURE);
}