1 /*
2 * Copyright (c) 2021 Jonathan Hahn
3 *
4 * SPDX-License-Identifier: Apache-2.0
5 */
6
7 #include <stdio.h>
8 #include <zephyr/kernel.h>
9 #include <zephyr/device.h>
10 #include <zephyr/drivers/sensor.h>
11
12 #define SAMPLING_INTERVAL_MS 10
13 #define DISPLAY_INTERVAL_MS 50
14
set_sampling_frequency(const struct device * sensor,double sampling_frequency)15 static int set_sampling_frequency(const struct device *sensor, double sampling_frequency)
16 {
17 struct sensor_value setting;
18
19 (void)sensor_value_from_double(&setting, sampling_frequency);
20
21 return sensor_attr_set(sensor,
22 SENSOR_CHAN_GYRO_XYZ, SENSOR_ATTR_SAMPLING_FREQUENCY, &setting);
23 }
24
fetch_and_display(const struct device * sensor)25 static void fetch_and_display(const struct device *sensor)
26 {
27 struct sensor_value gyro[3];
28
29 int rc = sensor_sample_fetch(sensor);
30
31 if (rc != 0) {
32 printf("ERROR: Failed fetching gyro values: %d.\n", rc);
33 return;
34 }
35
36 rc = sensor_channel_get(sensor,
37 SENSOR_CHAN_GYRO_XYZ,
38 gyro);
39
40 if (rc != 0) {
41 printf("ERROR: Failed getting gyro values: %d\n", rc);
42 return;
43 }
44
45 printf("%u ms: x %f , y %f , z %f\n",
46 k_uptime_get_32(),
47 sensor_value_to_double(&gyro[0]),
48 sensor_value_to_double(&gyro[1]),
49 sensor_value_to_double(&gyro[2]));
50 }
51
main(void)52 int main(void)
53 {
54 const double sampling_frequency = 1000.0 / SAMPLING_INTERVAL_MS;
55 const struct device *const sensor = DEVICE_DT_GET_ONE(st_i3g4250d);
56
57 if (!device_is_ready(sensor)) {
58 printf("Sensor %s is not ready\n", sensor->name);
59 return 0;
60 }
61
62 printf("Set sensor sampling frequency to %f Hz.\n", sampling_frequency);
63 set_sampling_frequency(sensor, sampling_frequency);
64
65 printf("Start polling with an interval of %d ms\n", DISPLAY_INTERVAL_MS);
66 while (true) {
67 fetch_and_display(sensor);
68
69 /* Wait some time before printing the next value */
70 k_sleep(K_MSEC(DISPLAY_INTERVAL_MS));
71 }
72 return 0;
73 }
74
