new new DHT11 data format handling

RIOT-OS · Jun 12, 2023 · 44ebdad · 44ebdad
1 parent 0672ac1
commit 44ebdad
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Showing 3 changed files with 16 additions and 0 deletions.
diff --git a/drivers/dht/dht.c b/drivers/dht/dht.c
@@ -153,6 +153,15 @@ static int _parse_raw_values(dht_t *dev, uint8_t *data)
          * abs() of value (beware: this is not two's complement!) */
         is_negative = data[BYTEPOS_TEMPERATURE_LOW] & 0x80;
         data[BYTEPOS_TEMPERATURE_LOW] &= ~0x80;
+        /* 2022-12 aosong.com data sheet uses interprets low bits as
+         * 0.01°C per LSB */
+        if (!dev->params.lsb_is_hundreds && data[BYTEPOS_TEMPERATURE_LOW] > 9) {
+            /* in case of miss configuration */
+            dev->params.lsb_is_hundreds = 1;
+        }
+        if (dev->params.lsb_is_hundreds) {
+            data[BYTEPOS_TEMPERATURE_LOW] /= 10;
+        }
         dev->last_val.temperature = data[BYTEPOS_TEMPERATURE_HIGH] * 10
                                   + data[BYTEPOS_TEMPERATURE_LOW];
         break;

diff --git a/drivers/dht/include/dht_params.h b/drivers/dht/include/dht_params.h
@@ -37,12 +37,17 @@ extern "C" {
 #ifndef DHT_PARAM_TYPE
 #define DHT_PARAM_TYPE              (DHT11)
 #endif
+#ifndef DHT_PARAM_LSB_IS_HUNDREDS
+#define DHT_PARAM_LSB_IS_HUNDREDS   (0)
+#endif
 #ifndef DHT_PARAM_PULL
 #define DHT_PARAM_PULL              (GPIO_IN)
 #endif
 #ifndef DHT_PARAMS
 #define DHT_PARAMS                  { .pin     = DHT_PARAM_PIN,  \
                                       .type    = DHT_PARAM_TYPE, \
+                                      .lsb_is_hundreds = \
+                                      DHT_PARAM_LSB_IS_HUNDREDS, \
                                       .in_mode = DHT_PARAM_PULL }
 #endif
 #ifndef DHT_SAULINFO

diff --git a/drivers/include/dht.h b/drivers/include/dht.h
@@ -75,6 +75,8 @@ typedef enum {
 typedef struct {
     gpio_t pin;             /**< GPIO pin of the device's data pin */
     dht_type_t type;        /**< type of the DHT device */
+    bool lsb_is_hundreds;   /**< 2022-12 aosong.com data sheet uses interprets
+                             *   low bits as 0.01°C per LSB */
     gpio_mode_t in_mode;    /**< input pin configuration, with or without pull
                              *   resistor */
 } dht_params_t;