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#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);
}
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