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#include <sensors/dht22.h>
#ifdef CONFIG_IOE_SENSOR_DHT22
#define PP dht22_ports[pi]
#define PPP dht22_ports[dht22_measurement.pi]
#define TIMEOUT F_CPU/40000
#define STATUS_NONE 0
#define STATUS_COMPLETE 1
#define STATUS_TIMEOUT 2
#define PORT_SENSORW 4
#define PORT_SENSORRESP_L 3
#define PORT_SENSORRESP_H 2
#define PORT_H 1
#define PORT_L 0
struct {
uint8_t index;
uint8_t data[5];
volatile uint8_t status;
uint8_t pi;
uint8_t port_status;
} dht22_measurement;
inline void dht22_init(uint8_t pi) {
// Set port as output and set level hight
*(PP.DDR) |= PP.MASK;
*(PP.PORT) |= PP.MASK;
// Enable all pin change interrupts
PCIFR = 0xff;
}
inline void dht22_read_deac(uint8_t status) {
dht22_measurement.status = status;
// Disable pin change interrupt
*(PPP.PCMSK) &= ~PPP.PCMSK_MASK;
timer_disable(CONFIG_IOE_SENSOR_DHT22_TIMER);
}
// This is called from pcint.c
void dht22_read_pcint(void) {
switch (dht22_measurement.port_status) {
case PORT_L:
if (!(*(PPP.PIN) & PPP.MASK))
return;
dht22_measurement.port_status = PORT_H;
break;
case PORT_H:
if (*(PPP.PIN) & PPP.MASK)
return;
dht22_measurement.port_status = PORT_L;
register uint16_t val;
val = timer_value(CONFIG_IOE_SENSOR_DHT22_TIMER);
// TODO compare value
if (val < 1) {
dht22_measurement.data[dht22_measurement.index / 8]
}
if (++(dht22_measurement.index) == 40) {
dht22_read_deac(STATUS_COMPLETE);
return;
}
break;
default:
if (((*(PPP.PIN) & PPP.MASK) && dht22_measurement.port_status == 3)
|| !(*(PPP.PIN & PPP.MASK)))
return;
dht22_measurement.port_status--;
}
timer_reset(CONFIG_IOE_SENSOR_DHT22_TIMER);
}
void dht22_read_timer_overflow(void) {
dht22_read_deac(STATUS_TIMEOUT);
}
int8_t dht22_read(uint8_t pi, struct dht22_value *rh,
struct dht22_value *t) {
dht22_measurement.index = 0;
dht22_measurement.status = STATUS_NONE;
dht22_measurement.pi = pi;
dht22_measurement.port_status = PORT_SENSORW;
// Pull port down for 500us
*(PP.PORT) &= ~PP.MASK;
_delay_us(500);
// Initialize timer
timer_init(CONFIG_IOE_SENSOR_DHT22_TIMER, TIMER_DIVIDER_64);
timer_sethook(CONFIG_IOE_SENSOR_DHT22_TIMER,
dht22_read_timer_overflow);
// Set pin change interrupt
*(PP.PCMSK) |= PP.PCMSK_MASK;
// Set port as output and pull-up resistor
*(PP.DDR) &= ~PP.MASK;
*(PP.PORT) |= PP.MASK;
// Delay till reading is done
taskDelayTill(&(dht22_measurement.status));
// Copy data
rh->integral = dht22_measurement.data[0];
rh->decimal = dht22_measurement.data[1];
t->integral = dht22_measurement.data[2];
t->decimal = dht22_measurement.data[3];
// Check sum
uint8_t sum = dht22_measurement.data[0];
sum += dht22_measurement.data[1];
sum += dht22_measurement.data[2];
sum += dht22_measurement.data[3];
if (sum != dht22_measurement.data[4])
return 1;
return dht22_measurement.status - 1;
}
#endif /* CONFIG_IOE_SENSOR_SHT22 */
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