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111 lines
2.9 KiB
C
111 lines
2.9 KiB
C
/*
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* Copyright (C) 2018 Freie Universität Berlin
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*
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* This file is subject to the terms and conditions of the GNU Lesser
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* General Public License v2.1. See the file LICENSE in the top level
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* directory for more details.
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*/
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/**
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* @defgroup drivers_srf04 srf04 ultra sonic range finder
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* @ingroup drivers_sensors
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* @brief Device driver for the srf04 ultra sonic range finder
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* @{
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*
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* @file
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* @brief Device driver for the srf04 ultra sonic range finder
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*
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* @author Semjon Kerner <semjon.kerner@fu-berlin.de>
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*/
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#ifndef SRF04_H
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#define SRF04_H
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#include <stdint.h>
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#include <stdio.h>
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#include "periph/gpio.h"
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#include "xtimer.h"
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#ifdef __cplusplus
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extern "C" {
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#endif
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/**
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* @brief Status and error return codes
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*/
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enum {
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SRF04_OK = 0, /**< exit without error */
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SRF04_ERR_INVALID = -1, /**< error no valid measurement available*/
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SRF04_ERR_MEASURING = -2, /**< error sensor is measuring*/
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SRF04_ERR_GPIO = -3, /**< error initializing gpio*/
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};
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/**
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* @brief GPIO pins for srf04 device
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*/
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typedef struct {
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gpio_t trigger; /**< GPIO Port the trigger pin is connected to */
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gpio_t echo; /**< GPIO Port the echo pin is connected to */
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} srf04_params_t;
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/**
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* @brief Device descriptor for srf04 sensor
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*/
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typedef struct {
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srf04_params_t p; /**< GPIO Ports of device */
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int32_t distance; /**< raw time of flight distance */
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uint32_t time; /**< timestamp of trigger or echo */
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} srf04_t;
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/**
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* @brief Initialize gpio and interrupt
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*
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* @param[out] dev device descriptor of sensor to initialize
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* @param[in] params init param struct holding gpio trigger and echo pins
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*
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* @return SRF04_OK on success
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* @return SRF04_GPIO on gpio init failure
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*/
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int srf04_init(srf04_t *dev, const srf04_params_t *params);
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/**
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* @brief Triggers measurement
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*
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* @param[in] dev device descriptor of sensor
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*/
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void srf04_trigger(const srf04_t *dev);
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/**
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* @brief Returns time of flight in ms
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*
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* @note should not be invoked within 50 ms after triggering
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*
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* @param[in] dev device descriptor of sensor
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*
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* @return time of flight in ms
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* @return SRF04_MEASURING if measurement is in progress
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* @return SRF04_INVALID if no valid measurement is available
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*/
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int srf04_read(const srf04_t *dev);
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/**
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* @brief Convenience function triggers a measurement and returns distance
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*
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* @note This function will return after 50 ms once new data is available
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*
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* @param[in] dev device descriptor of sensor
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*
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* @return time of flight in mm
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* @return SRF04_MEASURING if measurement is in progress
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* @return SRF04_INVALID if no valid measurement is available
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*/
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int srf04_get_distance(const srf04_t *dev);
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#ifdef __cplusplus
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}
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#endif
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#endif /* SRF04_H */
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/** @} */
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