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samples: sensor: adt7420: rework for trigger testing

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When a trigger was enabled the original implementation would do
nothing more than print "Waiting for a threshold event", without
describing what such an event would look like.

Rework to maintain a window of +/- 0.5 Cel around the most recent
in-window temperature, and reset that window whenever a trigger occurs
or a non-trigger reading is outside the window.  Time-out and display
the temperature if no event occurs in a reasonable time.

Signed-off-by: Peter Bigot <peter.bigot@nordicsemi.no>
This commit is contained in:
Peter Bigot 2019-12-21 09:26:36 -06:00 • committed by Carles Cufí
commit ff5cadc52c
2 changed files with 110 additions and 26 deletions
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20
samples/sensor/adt7420/README.rst
View file

@ -8,7 +8,12 @@ Description
This sample application periodically (1Hz) measures the ambient temperature
in degrees Celsius. The result is written to the console.
Optionally, it also shows how to use the upper and lower threshold triggers.
When configured in trigger mode the update interval is 5 s, and the
sample maintains a |plusminus| 1 |deg| C window around a recent
temperature. As soon as the temperature goes outside the window an
interrupt causes the application to display an event and update the
upper and lower window boundaries.
References
**********
@ -44,11 +49,12 @@ Sample Output
.. code-block:: console
device is 0x20002b74, name is ADT7420
temperature 24.984375 C
temperature 24.968750 C
temperature 24.968750 C
temperature 24.968750 C
temperature 24.953125 C
*** Booting Zephyr OS build zephyr-v2.1.0-538-g12b2ed2cf7c3 ***
device is 0x2000101c, name is ADT7420
[0:00:00.011]: temperature 21.203125 Cel
[0:00:01.015]: temperature 21.171875 Cel
[0:00:02.019]: temperature 21.171875 Cel
[0:00:03.023]: temperature 21.187500 Cel
[0:00:04.027]: temperature 21.140625 Cel
<repeats endlessly>

116
samples/sensor/adt7420/src/main.c
View file

@ -10,21 +10,51 @@
#include <stdio.h>
#include <sys/__assert.h>
K_SEM_DEFINE(sem, 0, 1);
#define DELAY_WITH_TRIGGER K_SECONDS(5)
#define DELAY_WITHOUT_TRIGGER K_SECONDS(1)
#define UCEL_PER_CEL 1000000
#define UCEL_PER_MCEL 1000
#define TEMP_INITIAL_CEL 21
#define TEMP_WINDOW_HALF_UCEL 500000
K_SEM_DEFINE(sem, 0, 1);
static const char *now_str(void)
{
static char buf[16]; /* ...HH:MM:SS.MMM */
u32_t now = k_uptime_get_32();
unsigned int ms = now % MSEC_PER_SEC;
unsigned int s;
unsigned int min;
unsigned int h;
now /= MSEC_PER_SEC;
s = now % 60U;
now /= 60U;
min = now % 60U;
now /= 60U;
h = now;
snprintf(buf, sizeof(buf), "%u:%02u:%02u.%03u",
h, min, s, ms);
return buf;
}
static void trigger_handler(struct device *dev, struct sensor_trigger *trigger)
{
k_sem_give(&sem);
}
static int low_ucel;
static int high_ucel;
static int sensor_set_attribute(struct device *dev, enum sensor_channel chan,
enum sensor_attribute attr, int value)
{
struct sensor_value sensor_val;
int ret;
sensor_val.val1 = value / 1000000;
sensor_val.val2 = value % 1000000;
sensor_val.val1 = value / UCEL_PER_CEL;
sensor_val.val2 = value % UCEL_PER_CEL;
ret = sensor_attr_set(dev, chan, attr, &sensor_val);
if (ret) {
@ -34,10 +64,43 @@ static int sensor_set_attribute(struct device *dev, enum sensor_channel chan,
return ret;
}
static bool temp_in_window(const struct sensor_value *val)
{
int temp_ucel = val->val1 * UCEL_PER_CEL + val->val2;
return (temp_ucel >= low_ucel) && (temp_ucel <= high_ucel);
}
static int sensor_set_window(struct device *dev,
const struct sensor_value *val)
{
int temp_ucel = val->val1 * UCEL_PER_CEL + val->val2;
low_ucel = temp_ucel - TEMP_WINDOW_HALF_UCEL;
high_ucel = temp_ucel + TEMP_WINDOW_HALF_UCEL;
int rc = sensor_set_attribute(dev, SENSOR_CHAN_AMBIENT_TEMP,
SENSOR_ATTR_UPPER_THRESH, high_ucel);
if (rc == 0) {
sensor_set_attribute(dev, SENSOR_CHAN_AMBIENT_TEMP,
SENSOR_ATTR_LOWER_THRESH, low_ucel);
}
if (rc == 0) {
printk("Alert on temp outside [%d, %d] mCel\n",
low_ucel / UCEL_PER_MCEL,
high_ucel / UCEL_PER_MCEL);
}
return rc;
}
static void process(struct device *dev)
{
struct sensor_value temp_val;
int ret;
bool reset_window = false;
/* Set upddate rate to 240 mHz */
sensor_set_attribute(dev, SENSOR_CHAN_AMBIENT_TEMP,
@ -48,25 +111,21 @@ static void process(struct device *dev)
.type = SENSOR_TRIG_THRESHOLD,
.chan = SENSOR_CHAN_AMBIENT_TEMP,
};
struct sensor_value val = {
.val1 = TEMP_INITIAL_CEL,
};
/* Set lower and upper threshold to 10 and 30 °C */
sensor_set_attribute(dev, SENSOR_CHAN_AMBIENT_TEMP,
SENSOR_ATTR_UPPER_THRESH, 30 * 1000000);
sensor_set_attribute(dev, SENSOR_CHAN_AMBIENT_TEMP,
SENSOR_ATTR_LOWER_THRESH, 10 * 1000000);
if (sensor_trigger_set(dev, &trig, trigger_handler)) {
ret = sensor_set_window(dev, &val);
if (ret == 0) {
ret = sensor_trigger_set(dev, &trig, trigger_handler);
}
if (ret != 0) {
printf("Could not set trigger\n");
return;
}
}
while (1) {
if (IS_ENABLED(CONFIG_ADT7420_TRIGGER)) {
printf("Waiting for a threshold event\n");
k_sem_take(&sem, K_FOREVER);
}
ret = sensor_sample_fetch(dev);
if (ret) {
printf("sensor_sample_fetch failed ret %d\n", ret);
@ -80,11 +139,30 @@ static void process(struct device *dev)
return;
}
printf("temperature %.6f C\n",
sensor_value_to_double(&temp_val));
if (IS_ENABLED(CONFIG_ADT7420_TRIGGER)) {
reset_window |= !temp_in_window(&temp_val);
}
if (!IS_ENABLED(CONFIG_ADT7420_TRIGGER)) {
k_sleep(K_MSEC(1000));
printf("[%s]: temperature %.6f Cel%s\n", now_str(),
sensor_value_to_double(&temp_val),
reset_window ? ": NEED RESET" : "");
if (IS_ENABLED(CONFIG_ADT7420_TRIGGER)) {
if (reset_window) {
ret = sensor_set_window(dev, &temp_val);
}
if (ret) {
printf("Window update failed ret %d\n", ret);
return;
}
printk("Wait for trigger...");
ret = k_sem_take(&sem, DELAY_WITH_TRIGGER);
reset_window = (ret == 0);
printk("%s\n", reset_window ? "ALERTED!" : "timed-out");
} else {
k_sleep(DELAY_WITHOUT_TRIGGER);
}
}
}