#include "project.h"

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

static unsigned poke;

static int pressure;

uint16_t pressure_ch (void)
{
  return pressure;
}




void pressure_tick (void)
{
  static unsigned ticker;

  ticker++;

  if (ticker < MS_TO_TICKS (2500))
    return;

  ticker = 0;
  poke = 1;

}




void pressure_dispatch (void)
{
  int v, r;

  if (!poke) return;

  poke = 0;

  if (adc_calibrate()) {
    pressure = 0;
    return;
  }

  v = adc_convert (PRESSURE_CHANNEL);
  r = adc_convert (VREF_CHANNEL);


  /* 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;
  }

  pressure = ((v * 552) / r) - 221;

  if (pressure < 0) pressure = 0;

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

}



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