Skip to content
New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

drivers/dht: reversal of #16934 regression #19674

Closed
wants to merge 1 commit into from
Closed

drivers/dht: reversal of #16934 regression #19674

Show file tree
Hide file tree
Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
64 changes: 45 additions & 19 deletions drivers/dht/dht.c
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -68,7 +68,12 @@ static inline void _reset(dht_t *dev)
static inline int _wait_for_level(gpio_t pin, bool expect, unsigned timeout)
{
while (((gpio_read(pin) > 0) != expect) && timeout) {
xtimer_usleep(1);
/* On AVR MCUs this loop already take more than 1 µs
* (3µs on a 16 MHz atmega328p), so we don't need to
* add further delay */
#ifndef __AVR__
xtimer_spin(xtimer_ticks_from_usec(1));
#endif
timeout--;
}

Expand Down Expand Up @@ -111,13 +116,14 @@ int dht_init(dht_t *dev, const dht_params_t *params)

/* check parameters and configuration */
assert(dev && params);
assert((params->type == DHT11) || (params->type == DHT22) || (params->type == DHT21));

memset(dev, 0, sizeof(dht_t));
dev->params = *params;

_reset(dev);

xtimer_msleep(2000);
xtimer_sleep(2);

DEBUG("[dht] dht_init: success\n");
return DHT_OK;
Expand All @@ -126,7 +132,7 @@ int dht_init(dht_t *dev, const dht_params_t *params)
int dht_read(dht_t *dev, int16_t *temp, int16_t *hum)
{
uint8_t csum;
uint8_t raw_temp_i, raw_temp_d, raw_hum_i, raw_hum_d;
uint8_t raw_temp_h, raw_temp_l, raw_hum_h, raw_hum_l;

assert(dev);

Expand All @@ -136,7 +142,7 @@ int dht_read(dht_t *dev, int16_t *temp, int16_t *hum)
gpio_clear(dev->params.pin);
xtimer_usleep(START_LOW_TIME);
gpio_set(dev->params.pin);
xtimer_usleep(START_HIGH_TIME);
xtimer_spin(xtimer_ticks_from_usec(START_HIGH_TIME));

/* sync on device */
gpio_init(dev->params.pin, dev->params.in_mode);
Expand All @@ -157,19 +163,19 @@ int dht_read(dht_t *dev, int16_t *temp, int16_t *hum)
*/

/* read the humidity, temperature, and checksum bits */
if (_read(&raw_hum_i, dev->params.pin)) {
if (_read(&raw_hum_h, dev->params.pin)) {
_reset(dev);
return DHT_TIMEOUT;
}
if (_read(&raw_hum_d, dev->params.pin)) {
if (_read(&raw_hum_l, dev->params.pin)) {
_reset(dev);
return DHT_TIMEOUT;
}
if (_read(&raw_temp_i, dev->params.pin)) {
if (_read(&raw_temp_h, dev->params.pin)) {
_reset(dev);
return DHT_TIMEOUT;
}
if (_read(&raw_temp_d, dev->params.pin)) {
if (_read(&raw_temp_l, dev->params.pin)) {
_reset(dev);
return DHT_TIMEOUT;
}
Expand All @@ -184,23 +190,43 @@ int dht_read(dht_t *dev, int16_t *temp, int16_t *hum)
_reset(dev);

/* validate the checksum */
uint8_t sum = (raw_temp_i) + (raw_temp_d) + (raw_hum_i) + (raw_hum_d);
uint8_t sum = (raw_hum_h) + (raw_hum_l) + (raw_temp_h) + (raw_temp_l);
if (sum != csum) {
DEBUG("[dht] error: checksum doesn't match\n");
return DHT_NOCSUM;
}

/* parse the RAW values */
DEBUG("[dht] RAW values: temp: %2i.%i hum: %2i.%i\n", (int)raw_temp_i,
(int)raw_temp_d, (int)raw_hum_i, (int)raw_hum_d);

dev->last_val.humidity = raw_hum_i * 10 + raw_hum_d;
/* MSB set means negative temperature on DHT22. Will always be 0 on DHT11 */
if (raw_temp_i & 0x80) {
dev->last_val.temperature = -((raw_temp_i & ~0x80) * 10 + raw_temp_d);
}
else {
dev->last_val.temperature = raw_temp_i * 10 + raw_temp_d;
DEBUG("[dht] type: %d\n"
"\tRAW values: raw_hum_h: 0x%2x raw_hum_l: 0x%2x\n"
"\t\traw_temp_h: 0x%2x raw_temp_l: 0x%2x\n", dev->params.type,
(int)raw_hum_h, (int)raw_hum_l, (int)raw_temp_h, (int)raw_temp_l);
switch (dev->params.type) {
case DHT11:
dev->last_val.humidity = raw_hum_h * 10 + raw_hum_l;
if (raw_temp_l & 0x80) {
dev->last_val.temperature
= (raw_temp_h * 10 + (raw_temp_l & ~0x80)) * -1;
}
else {
dev->last_val.temperature = raw_temp_h * 10 + raw_temp_l;
}
break;
/* DHT21 == DHT22 (same value in enum), so both are handled here */
case DHT22:
dev->last_val.humidity = (int16_t)((raw_hum_h << 8) | raw_hum_l);
/* if the high-bit is set, the value is negative */
if (raw_temp_h & 0x80) {
dev->last_val.temperature
= ((int16_t)(((raw_temp_h & ~0x80) << 8) | raw_temp_l)) * -1;
}
else {
dev->last_val.temperature
= (int16_t)((raw_temp_h << 8) | raw_temp_l);
}
break;
default:
return DHT_NODEV; /* this should never be reached */
}

/* update time of last measurement */
Expand Down
4 changes: 4 additions & 0 deletions drivers/dht/include/dht_params.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -34,11 +34,15 @@ extern "C" {
#ifndef DHT_PARAM_PIN
#define DHT_PARAM_PIN (GPIO_PIN(0, 0))
#endif
#ifndef DHT_PARAM_TYPE
#define DHT_PARAM_TYPE (DHT11)
#endif
#ifndef DHT_PARAM_PULL
#define DHT_PARAM_PULL (GPIO_IN_PU)
#endif
#ifndef DHT_PARAMS
#define DHT_PARAMS { .pin = DHT_PARAM_PIN, \
.type = DHT_PARAM_TYPE, \
.in_mode = DHT_PARAM_PULL }
#endif
#ifndef DHT_SAULINFO
Expand Down
14 changes: 13 additions & 1 deletion drivers/include/dht.h
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -46,21 +46,33 @@ enum {
DHT_OK = 0, /**< all good */
DHT_NOCSUM = -1, /**< checksum error */
DHT_TIMEOUT = -2, /**< communication timed out */
DHT_NODEV = -3 /**< device type not defined */
};

/**
* @brief Data type for storing DHT sensor readings
*/
typedef struct {
uint16_t humidity; /**< relative percent */
uint16_t humidity; /**< relative humidity in deci-percent */
uint16_t temperature; /**< temperature in deci-Celsius */
} dht_data_t;

/**
* @brief Device type of the DHT device
*/
typedef enum {
DHT11, /**< DHT11 device identifier */
DHT22, /**< DHT22 device identifier */
DHT21 = DHT22, /**< DHT21 device identifier */
AM2301 = DHT22, /**< AM2301 device identifier */
} dht_type_t;

/**
* @brief Configuration parameters for DHT devices
*/
typedef struct {
gpio_t pin; /**< GPIO pin of the device's data pin */
dht_type_t type; /**< type of the DHT device */
gpio_mode_t in_mode; /**< input pin configuration, with or without pull
* resistor */
} dht_params_t;
Expand Down