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#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);
}
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