inspektors/robot/include/sonar.h

#ifndef SONAR_H
#define SONAR_H

#include "common.h"

// Trigger
#define TRIG_DDR    DDRC
#define TRIG_PORT   PORTC
#define TRIG_PIN    PINC
#define TRIG_BIT    PC4

// Echo
#define ECHO_DDR    DDRC
#define ECHO_PORT   PORTC
#define ECHO_PIN    PINC
#define ECHO_BIT    PC5

#define SPEED_OF_SOUND      343 // 20°C dry air (m/s)
#define MAX_SONAR_RANGE     8 // Trigger + echo (m)
#define MIN_SONAR_RANGE     3 // Minimum distance that is still reliable
#define SONAR_DELAY	        60 // Timeout for return signal
#define TIMER_MAX           65535 // For 16-bit timer
#define CYCLES_PER_US       (F_CPU / 1000000)
#define SONAR_TIMEOUT 	    (F_CPU * MAX_SONAR_RANGE) / SPEED_OF_SOUND

#define ECHO_TIMEOUT -1

void init_sonar(void);
int32_t read_sonar(void);

#endif /* SONAR_H */