Merge pull request #632 from adafruit/scd30-read-data-at-once

Add retry if data not ready for SCD30

Author: tyeth

src/components/i2c/drivers/WipperSnapper_I2C_Driver_SCD30.h

@@ -53,6 +53,56 @@ class WipperSnapper_I2C_Driver_SCD30 : public WipperSnapper_I2C_Driver {
     return _scd->begin((uint8_t)_sensorAddress, _i2c);
   }
 
+  /*******************************************************************************/
+  /*!
+      @brief    Checks if sensor was read within last 1s, or is the first read.
+      @returns  True if the sensor was recently read, False otherwise.
+  */
+  bool alreadyRecentlyRead() {
+    return (_lastRead != 0 && millis() - _lastRead) < 1000;
+  }
+
+  /*******************************************************************************/
+  /*!
+      @brief    Checks if the sensor is ready to be read
+      @returns  True if the sensor is ready, False otherwise.
+  */
+  /*******************************************************************************/
+  bool sensorReady() {
+    if (!_scd->dataReady()) {
+      // failed, one more quick attempt
+      delay(100);
+      if (!_scd->dataReady()) {
+        return false;
+      }
+    }
+    return true;
+  }
+
+  /*******************************************************************************/
+  /*!
+      @brief    Reads the SCD30 sensor.
+      @returns  True if the sensor was read successfully, False otherwise.
+  */
+  /*******************************************************************************/
+  bool readSensorData() {
+    // dont read sensor more than once per second
+    if (alreadyRecentlyRead()) {
+      return true;
+    }
+
+    if (!sensorReady()) {
+      return false;
+    }
+
+    if (_scd->getEvent(&_humidity, &_temperature)) {
+      return false;
+    }
+    _CO2.CO2 = _scd->CO2;
+    _lastRead = millis();
+    return true;
+  }
+
   /*******************************************************************************/
   /*!
       @brief    Gets the SCD30's current temperature.
@@ -64,14 +114,11 @@ class WipperSnapper_I2C_Driver_SCD30 : public WipperSnapper_I2C_Driver {
   /*******************************************************************************/
   bool getEventAmbientTemp(sensors_event_t *tempEvent) {
     // check if sensor is enabled and data is available
-    if (_tempSensorPeriod != 0 && (!_scd->dataReady()))
-      return false;
-
-    // attempt to get temperature data
-    sensors_event_t humidEvent;
-    if (!_scd->getEvent(&humidEvent, tempEvent))
+    if (!readSensorData()) {
       return false;
+    }
 
+    tempEvent = &_temperature;
     return true;
   }
 
@@ -86,14 +133,11 @@ class WipperSnapper_I2C_Driver_SCD30 : public WipperSnapper_I2C_Driver {
   /*******************************************************************************/
   bool getEventRelativeHumidity(sensors_event_t *humidEvent) {
     // check if sensor is enabled and data is available
-    if (_humidSensorPeriod != 0 && (!_scd->dataReady()))
-      return false;
-
-    // attempt to get temperature data
-    sensors_event_t tempEvent;
-    if (!_scd->getEvent(humidEvent, &tempEvent))
+    if (!readSensorData()) {
       return false;
+    }
 
+    humidEvent = &_humidity;
     return true;
   }
 
@@ -108,15 +152,20 @@ class WipperSnapper_I2C_Driver_SCD30 : public WipperSnapper_I2C_Driver {
   /*******************************************************************************/
   bool getEventCO2(sensors_event_t *co2Event) {
     // check if sensor is enabled and data is available
-    if (_CO2SensorPeriod != 0 && (!_scd->dataReady()))
+    if (!readSensorData()) {
       return false;
+    }
 
-    co2Event->CO2 = _scd->CO2;
+    co2Event = &_CO2;
     return true;
   }
 
 protected:
-  Adafruit_SCD30 *_scd; ///< SCD30 driver object
+  Adafruit_SCD30 *_scd = nullptr; ///< SCD30 driver object
+  ulong _lastRead = 0;            ///< Last time the sensor was read
+  sensors_event_t _temperature;   ///< Temperature
+  sensors_event_t _humidity;      ///< Relative Humidity
+  sensors_event_t _CO2;           ///< CO2
 };
 
 #endif // WipperSnapper_I2C_Driver_SCD30