porklib: Simple library for programming Arduino in C
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avr-lib/lib/sonar.h

70 lines
1.6 KiB

#pragma once
//
// Utilities for working with the HC-SR04 ultrasonic sensor
// Can be easily modified to work with other similar modules
//
// It's required that you call the sonar_handle_* functions from your ISRs
// See example program for more info.
//
#include <stdint.h>
#include <stdbool.h>
#include "lib/pins.h"
// Calib constant for the module
// CM = uS / _DIV_CONST
#define _SNR_DIV_CONST 58
// Max module distance in MM
#define _SNR_MAX_DIST 4000
// Trigger time in uS
#define _SNR_TRIG_TIME 10
// Sonar data object
typedef struct {
PORT_P port; // Tx PORT
uint8_t ntx; // Tx bit number
PORT_P pin; // Rx PIN
uint8_t nrx; // Rx bit number
uint8_t bank; // Rx PCINT bank
} sonar_t;
// Create a Sonar port
// Args: sonar_t* so, Trig pin, Echo pin
#define sonar_init(so, trig, echo) do { \
as_output(io_pack(trig)); \
as_input_pu(io_pack(echo)); \
_sonar_init_do(so, &io2port(io_pack(trig)), io2n(io_pack(trig)), &io2pin(io_pack(echo)), io2n(io_pack(echo))); \
} while(0)
// private, in header because of the macro.
void _sonar_init_do(sonar_t* so, PORT_P port, uint8_t ntx, PORT_P pin, uint8_t nrx);
/** Check if sonar is busy */
bool sonar_busy();
/** Get result of last measurement, in millimeters. Returns -1 if no obstacle detected */
int16_t sonar_result();
/**
* Start sonar measurement
* Interrupts must be enabled
* TIMER 1 will be used for the async measurement
*/
bool sonar_start(sonar_t* so);
/** Handle TIMER1_OVF (returns true if consumed) */
bool sonar_handle_t1ovf();
/** Handle pin change interrupt (returns true if consumed) */
bool sonar_handle_pci();