From b24de4a22a6f98c7bac3afa915e0a1b2246c6404 Mon Sep 17 00:00:00 2001
From: Semjon Kerner <semjon.kerner@fu-berlin.de>
Date: Thu, 20 Sep 2018 13:00:57 +0200
Subject: [PATCH] drivers/srf04: initial driver implementation
---
drivers/Makefile.dep | 6 ++
drivers/Makefile.include | 4 +
drivers/include/srf04.h | 110 +++++++++++++++++++++++++++
drivers/srf04/Makefile | 1 +
drivers/srf04/include/srf04_params.h | 62 +++++++++++++++
drivers/srf04/srf04.c | 95 +++++++++++++++++++++++
6 files changed, 278 insertions(+)
create mode 100644 drivers/include/srf04.h
create mode 100644 drivers/srf04/Makefile
create mode 100644 drivers/srf04/include/srf04_params.h
create mode 100644 drivers/srf04/srf04.c
diff --git a/drivers/Makefile.dep b/drivers/Makefile.dep
index cf30a71667..e5a0c9991d 100644
--- a/drivers/Makefile.dep
+++ b/drivers/Makefile.dep
@@ -405,6 +405,12 @@ ifneq (,$(filter srf02,$(USEMODULE)))
USEMODULE += xtimer
endif
+ifneq (,$(filter srf04,$(USEMODULE)))
+ USEMODULE += xtimer
+ FEATURES_REQUIRED += periph_gpio
+ FEATURES_REQUIRED += periph_gpio_irq
+endif
+
ifneq (,$(filter srf08,$(USEMODULE)))
FEATURES_REQUIRED += periph_i2c
USEMODULE += xtimer
diff --git a/drivers/Makefile.include b/drivers/Makefile.include
index 11cc60b374..83c994ef37 100644
--- a/drivers/Makefile.include
+++ b/drivers/Makefile.include
@@ -222,6 +222,10 @@ ifneq (,$(filter soft_spi,$(USEMODULE)))
USEMODULE_INCLUDES += $(RIOTBASE)/drivers/soft_spi/include
endif
+ifneq (,$(filter srf04,$(USEMODULE)))
+ USEMODULE_INCLUDES += $(RIOTBASE)/drivers/srf04/include
+endif
+
ifneq (,$(filter sx127x,$(USEMODULE)))
USEMODULE_INCLUDES += $(RIOTBASE)/drivers/sx127x/include
endif
diff --git a/drivers/include/srf04.h b/drivers/include/srf04.h
new file mode 100644
index 0000000000..3856b34f0f
--- /dev/null
+++ b/drivers/include/srf04.h
@@ -0,0 +1,110 @@
+/*
+ * Copyright (C) 2018 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @defgroup drivers_srf04 srf04 ultra sonic range finder
+ * @ingroup drivers_sensors
+ * @brief Device driver for the srf04 ultra sonic range finder
+ * @{
+ *
+ * @file
+ * @brief Device driver for the srf04 ultra sonic range finder
+ *
+ * @author Semjon Kerner <semjon.kerner@fu-berlin.de>
+ */
+
+#ifndef SRF04_H
+#define SRF04_H
+
+#include <stdint.h>
+#include <stdio.h>
+
+#include "periph/gpio.h"
+#include "xtimer.h"
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+/**
+ * @brief Status and error return codes
+ */
+enum {
+ SRF04_OK = 0, /**< exit without error */
+ SRF04_ERR_INVALID = -1, /**< error no valid measurement available*/
+ SRF04_ERR_MEASURING = -2, /**< error sensor is measuring*/
+ SRF04_ERR_GPIO = -3, /**< error initializing gpio*/
+};
+
+/**
+ * @brief GPIO pins for srf04 device
+ */
+typedef struct {
+ gpio_t trigger; /**< GPIO Port the trigger pin is connected to */
+ gpio_t echo; /**< GPIO Port the echo pin is connected to */
+} srf04_params_t;
+
+/**
+ * @brief Device descriptor for srf04 sensor
+ */
+typedef struct {
+ srf04_params_t p; /**< GPIO Ports of device */
+ int distance; /**< raw time of flight distance */
+ uint32_t time; /**< timestamp of trigger or echo */
+} srf04_t;
+
+/**
+ * @brief Initialize gpio and interrupt
+ *
+ * @param[out] dev device descriptor of sensor to initialize
+ * @param[in] params init param struct holding gpio trigger and echo pins
+ *
+ * @return SRF04_OK on success
+ * @return SRF04_GPIO on gpio init failure
+ */
+int srf04_init(srf04_t *dev, const srf04_params_t *params);
+
+/**
+ * @brief Triggers measurement
+ *
+ * @param[in] dev device descriptor of sensor
+ */
+void srf04_trigger(const srf04_t *dev);
+
+/**
+ * @brief Returns time of flight in ms
+ *
+ * @note should not be invoked within 50 ms after triggering
+ *
+ * @param[in] dev device descriptor of sensor
+ *
+ * @return time of flight in ms
+ * @return SRF04_MEASURING if measurement is in progress
+ * @return SRF04_INVALID if no valid measurement is available
+ */
+int srf04_read(const srf04_t* dev);
+
+/**
+ * @brief Convenience function triggers a measurement and returns distance
+ *
+ * @note This function will return after 50 ms once new data is available
+ *
+ * @param[in] dev device descriptor of sensor
+ *
+ * @return time of flight in mm
+ * @return SRF04_MEASURING if measurement is in progress
+ * @return SRF04_INVALID if no valid measurement is available
+ */
+int srf04_get_distance(const srf04_t* dev);
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SRF04_H */
+/** @} */
diff --git a/drivers/srf04/Makefile b/drivers/srf04/Makefile
new file mode 100644
index 0000000000..48422e909a
--- /dev/null
+++ b/drivers/srf04/Makefile
@@ -0,0 +1 @@
+include $(RIOTBASE)/Makefile.base
diff --git a/drivers/srf04/include/srf04_params.h b/drivers/srf04/include/srf04_params.h
new file mode 100644
index 0000000000..fddcfd046d
--- /dev/null
+++ b/drivers/srf04/include/srf04_params.h
@@ -0,0 +1,62 @@
+/*
+ * Copyright (C) 2018 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup drivers_srf04
+ *
+ * @{
+ * @file
+ * @brief Default configuration for srf04 devices
+ *
+ * @author Semjon Kerner <semjon.kerner@fu-berlin.de>
+ */
+
+#ifndef SRF04_PARAMS_H
+#define SRF04_PARAMS_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+#include "board.h"
+#include "srf04.h"
+
+/**
+ * @name Default configuration parameters for SRF04 device
+ * @{
+ */
+#ifndef SRF04_PARAM_TRIGGER
+#define SRF04_PARAM_TRIGGER GPIO_PIN(0,13)
+#endif
+#ifndef SRF04_PARAM_ECHO
+#define SRF04_PARAM_ECHO GPIO_PIN(0,14)
+#endif
+
+#ifndef SRF04_PARAMS
+#define SRF04_PARAMS \
+ { .trigger = SRF04_PARAM_TRIGGER, \
+ .echo = SRF04_PARAM_ECHO, \
+ }
+#endif
+/** @} */
+
+/**
+ * @brief SRF04 configuration
+ */
+static const srf04_params_t srf04_params[] = {
+ SRF04_PARAMS
+};
+
+#define SRF04_NUMOF (sizeof(srf04_params) / sizeof(srf04_params[0]))
+
+#ifdef __cplusplus
+}
+#endif
+
+#endif /* SRF04_PARAMS_H */
+/** @} */
diff --git a/drivers/srf04/srf04.c b/drivers/srf04/srf04.c
new file mode 100644
index 0000000000..d828ed7d85
--- /dev/null
+++ b/drivers/srf04/srf04.c
@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2018 Freie Universität Berlin
+ *
+ * This file is subject to the terms and conditions of the GNU Lesser
+ * General Public License v2.1. See the file LICENSE in the top level
+ * directory for more details.
+ */
+
+/**
+ * @ingroup drivers_srf04
+ * @{
+ *
+ * @file
+ * @brief driver for srf04 ultra sonic range finder
+ *
+ * @author Semjon Kerner <semjon.kerner@fu-berlin.de>
+ *
+ * @}
+ */
+
+#include "srf04.h"
+#include "srf04_params.h"
+
+#define ENABLE_DEBUG (0)
+#include "debug.h"
+
+#define SRF04_DISTANCE (584U)
+#define SRF04_SAMPLE_PERIOD (50U * US_PER_MS)
+
+static void _cb(void *arg)
+{
+ uint32_t t = xtimer_now_usec();
+
+ srf04_t* dev = (srf04_t*)arg;
+ if (dev->distance > SRF04_ERR_MEASURING) {
+ dev->distance = SRF04_ERR_MEASURING;
+ dev->time = t;
+ } else {
+ gpio_irq_disable(dev->p.echo);
+ dev->distance = (t - dev->time);
+ }
+}
+
+int srf04_init(srf04_t* dev, const srf04_params_t *params)
+{
+ dev->p = *params;
+
+ dev->distance = SRF04_ERR_INVALID;
+ dev->time = 0;
+
+ if (gpio_init(dev->p.trigger, GPIO_OUT) != 0) {
+ DEBUG("[srf04] Error: could not initialize GPIO trigger pin\n");
+ return SRF04_ERR_GPIO;
+ }
+
+ if (gpio_init_int(dev->p.echo, GPIO_IN, GPIO_BOTH, _cb, (void*)dev) != 0) {
+ DEBUG("[srf04] Error: could not initialize GPIO echo pin\n");
+ return SRF04_ERR_GPIO;
+ }
+
+ gpio_irq_disable(dev->p.echo);
+
+ return SRF04_OK;
+}
+
+void srf04_trigger(const srf04_t* dev)
+{
+ if (dev->distance == SRF04_ERR_MEASURING) {
+ return;
+ }
+
+ gpio_irq_enable(dev->p.echo);
+
+ gpio_set(dev->p.trigger);
+ xtimer_usleep(10);
+ gpio_clear(dev->p.trigger);
+}
+
+int srf04_read(const srf04_t* dev)
+{
+ return dev->distance;
+}
+
+int srf04_get_distance(const srf04_t* dev)
+{
+ /* trigger new reading */
+ srf04_trigger(dev);
+ /* give the sensor the required time for sampling */
+ xtimer_usleep(SRF04_SAMPLE_PERIOD);
+ /* get the result */
+ if (dev->distance >= SRF04_OK) {
+ return ((dev->distance * 100) / SRF04_DISTANCE);
+ }
+ return dev->distance;
+}
--
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