Add isConnected(). Add test for readMeasurement() before returning reading.

Author: nseidle

keywords.txt

@@ -14,6 +14,7 @@ SCD30	KEYWORD1
 
 SCD30	KEYWORD2
 begin	KEYWORD2
+isConnected	KEYWORD2
 enableDebugging	KEYWORD2
 beginMeasuring	KEYWORD2
 StopMeasurement	KEYWORD2

src/SparkFun_SCD30_Arduino_Library.cpp

@@ -58,16 +58,9 @@ bool SCD30::begin(TwoWire &wirePort, bool autoCalibrate, bool measBegin)
   _i2cPort->setClockStretchLimit(200000);
 #endif
 
-  uint16_t fwVer;
-  if (getFirmwareVersion(&fwVer) == false) // Read the firmware version. Return false if the CRC check fails.
+  if (isConnected() == false)
     return (false);
 
-  if (_printDebug == true)
-  {
-    _debugPort->print(F("SCD30 begin: got firmware version 0x"));
-    _debugPort->println(fwVer, HEX);
-  }
-
   if (measBegin == false) // Exit now if measBegin is false
     return (true);
 
@@ -83,6 +76,22 @@ bool SCD30::begin(TwoWire &wirePort, bool autoCalibrate, bool measBegin)
   return (false); // Something went wrong
 }
 
+// Returns true if device responds to a firmware request
+bool SCD30::isConnected()
+{
+  uint16_t fwVer;
+  if (getFirmwareVersion(&fwVer) == false) // Read the firmware version. Return false if the CRC check fails.
+    return (false);
+
+  if (_printDebug == true)
+  {
+    _debugPort->print(F("Firmware version 0x"));
+    _debugPort->println(fwVer, HEX);
+  }
+
+  return (true);
+}
+
 // Calling this function with nothing sets the debug port to Serial
 // You can also call it with other streams like Serial1, SerialUSB, etc.
 void SCD30::enableDebugging(Stream &debugPort)
@@ -96,7 +105,11 @@ void SCD30::enableDebugging(Stream &debugPort)
 uint16_t SCD30::getCO2(void)
 {
   if (co2HasBeenReported == true) // Trigger a new read
-    readMeasurement();            // Pull in new co2, humidity, and temp into global vars
+  {
+    if (readMeasurement() == false) // Pull in new co2, humidity, and temp into global vars
+      co2 = 0;                      // Failed to read sensor
+  }
+
   co2HasBeenReported = true;
 
   return (uint16_t)co2; // Cut off decimal as co2 is 0 to 10,000
@@ -107,7 +120,8 @@ uint16_t SCD30::getCO2(void)
 float SCD30::getHumidity(void)
 {
   if (humidityHasBeenReported == true) // Trigger a new read
-    readMeasurement();                 // Pull in new co2, humidity, and temp into global vars
+    if (readMeasurement() == false)    // Pull in new co2, humidity, and temp into global vars
+      humidity = 0;                    // Failed to read sensor
 
   humidityHasBeenReported = true;
 
@@ -119,7 +133,8 @@ float SCD30::getHumidity(void)
 float SCD30::getTemperature(void)
 {
   if (temperatureHasBeenReported == true) // Trigger a new read
-    readMeasurement();                    // Pull in new co2, humidity, and temp into global vars
+    if (readMeasurement() == false)       // Pull in new co2, humidity, and temp into global vars
+      temperature = 0;                    // Failed to read sensor
 
   temperatureHasBeenReported = true;
 

src/SparkFun_SCD30_Arduino_Library.h

@@ -40,10 +40,10 @@
 #include <Wire.h>
 #endif
 
-//The default I2C address for the SCD30 is 0x61.
+// The default I2C address for the SCD30 is 0x61.
 #define SCD30_ADDRESS 0x61
 
-//Available commands
+// Available commands
 
 #define COMMAND_CONTINUOUS_MEASUREMENT 0x0010
 #define COMMAND_SET_MEASUREMENT_INTERVAL 0x4600
@@ -70,12 +70,13 @@ class SCD30
 
 	bool begin(bool autoCalibrate) { return begin(Wire, autoCalibrate); }
 #ifdef USE_TEENSY3_I2C_LIB
-	bool begin(i2c_t3 &wirePort = Wire, bool autoCalibrate = false, bool measBegin = true); //By default use Wire port
+	bool begin(i2c_t3 &wirePort = Wire, bool autoCalibrate = false, bool measBegin = true); // By default use Wire port
 #else
-	bool begin(TwoWire &wirePort = Wire, bool autoCalibrate = false, bool measBegin = true); //By default use Wire port
+	bool begin(TwoWire &wirePort = Wire, bool autoCalibrate = false, bool measBegin = true); // By default use Wire port
 #endif
 
-	void enableDebugging(Stream &debugPort = Serial); //Turn on debug printing. If user doesn't specify then Serial will be used.
+	bool isConnected();
+	void enableDebugging(Stream &debugPort = Serial); // Turn on debug printing. If user doesn't specify then Serial will be used.
 
 	bool beginMeasuring(uint16_t pressureOffset);
 	bool beginMeasuring(void);
@@ -120,25 +121,25 @@ class SCD30
 	uint8_t computeCRC8(uint8_t data[], uint8_t len);
 
 private:
-	//Variables
+	// Variables
 #ifdef USE_TEENSY3_I2C_LIB
-	i2c_t3 *_i2cPort; //The generic connection to user's chosen I2C hardware
+	i2c_t3 *_i2cPort; // The generic connection to user's chosen I2C hardware
 #else
-	TwoWire *_i2cPort;																		 //The generic connection to user's chosen I2C hardware
+	TwoWire *_i2cPort;																		 // The generic connection to user's chosen I2C hardware
 #endif
-	//Global main datums
+	// Global main datums
 	float co2 = 0;
 	float temperature = 0;
 	float humidity = 0;
 
-	//These track the staleness of the current data
-	//This allows us to avoid calling readMeasurement() every time individual datums are requested
+	// These track the staleness of the current data
+	// This allows us to avoid calling readMeasurement() every time individual datums are requested
 	bool co2HasBeenReported = true;
 	bool humidityHasBeenReported = true;
 	bool temperatureHasBeenReported = true;
 
-	//Debug
-	Stream *_debugPort;			 //The stream to send debug messages to if enabled. Usually Serial.
-	boolean _printDebug = false; //Flag to print debugging variables
+	// Debug
+	Stream *_debugPort;			 // The stream to send debug messages to if enabled. Usually Serial.
+	boolean _printDebug = false; // Flag to print debugging variables
 };
 #endif