Fix sensor determination.

Add command to return device type. Remove determineSensorType function. Replace with getFeatureSetVersion. Move setSensorType to public. Remove utility functions convertASCIIToHex and extractMaskedSensorType. Adapt begin function for new sensor function. Rev library version. Revise keywords.txt for the above changes.
sparkfun · Jun 13, 2023 · c682c6c · c682c6c
1 parent 67f3677
commit c682c6c
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Showing 5 changed files with 57 additions and 128 deletions.
diff --git a/examples/Example9_SensorType/Example9_SensorType.ino b/examples/Example9_SensorType/Example9_SensorType.ino
@@ -47,13 +47,10 @@ void setup()
       ;
   }
 
-  char serialNumber[13];
-  bool success = mySensor.getSerialNumber(serialNumber);
-  Serial.print(F("Serial Number is: "));
-  Serial.println(serialNumber);
-
-  Serial.print(F("Getting the sensor type: SCD4"));
-  Serial.println(mySensor.getSensorType());
+  scd4x_sensor_type_e sensor;
+  bool success = mySensor.getFeatureSetVersion(&sensor);
+  Serial.print(F("Sensor determined to by of type: SCD4"));
+  Serial.println(sensor);
 
 }
 

diff --git a/keywords.txt b/keywords.txt
@@ -38,8 +38,9 @@ measureSingleShotRHTOnly	KEYWORD2
 sendCommand	KEYWORD2
 readRegister	KEYWORD2
 computeCRC8	KEYWORD2
-determineSensorType KEYWORD2
+getFeatureSetVersion KEYWORD2
 getSensorType KEYWORD2
+setSensorType KEYWORD2
 
 #######################################
 # Constants (LITERAL1)
@@ -67,5 +68,6 @@ SCD4x_COMMAND_GET_SERIAL_NUMBER	LITERAL1
 SCD4x_COMMAND_PERFORM_SELF_TEST	LITERAL1
 SCD4x_COMMAND_PERFORM_FACTORY_RESET	LITERAL1
 SCD4x_COMMAND_REINIT	LITERAL1
+SCD4x_COMMAND_GET_FEATURE_SET_VERSION LITERAL1
 SCD4x_COMMAND_MEASURE_SINGLE_SHOT	LITERAL1
 SCD4x_COMMAND_MEASURE_SINGLE_SHOT_RHT_ONLY	LITERAL1
diff --git a/library.properties b/library.properties
@@ -1,5 +1,5 @@
 name=SparkFun SCD4x Arduino Library
-version=1.1.1
+version=1.1.2
 author=SparkFun Electronics
 maintainer=SparkFun Electronics <sparkfun.com>
 sentence=Library for the Sensirion SCD4x family of CO2 Sensors (SCD40 and SCD41)

diff --git a/src/SparkFun_SCD4x_Arduino_Library.cpp b/src/SparkFun_SCD4x_Arduino_Library.cpp
@@ -59,7 +59,7 @@ bool SCD4x::begin(TwoWire &wirePort, bool measBegin, bool autoCalibrate, bool sk
   if (pollAndSetDeviceType == true)
   {
     scd4x_sensor_type_e sensorType;
-    success &= determineSensorType(&sensorType, serialNumber);
+    success &= getFeatureSetVersion(&sensorType);
 
     setSensorType(sensorType);
 
@@ -870,27 +870,6 @@ char SCD4x::convertHexToASCII(uint8_t digit)
     return (char(digit + 0x41 - 10)); // Use upper case for A-F
 }
 
-void SCD4x::convertASCIIToHex(const char *hexstr, uint16_t *integers)
-{
-  for (int i = 0; i < 3; i++ ) {
-    uint16_t val = 0;
-    for (int j = 0; j < 4; j++ ) {
-      char c = hexstr[i * 4 + j];
-      val <<= 4;
-      if (c >= '0' && c <= '9') {
-        val += c - '0';
-      } 
-      else if (c >= 'A' && c <= 'F') {
-          val += c - 'A' + 10;
-      } 
-      else if (c >= 'a' && c <= 'f') {
-          val += c - 'a' + 10;
-      }
-    }
-    integers[i] = val;
-  }
-}
-
 //Perform self test. Takes 10 seconds to complete. See 3.9.3
 //The perform_self_test feature can be used as an end-of-line test to check sensor functionality
 //and the customer power supply to the sensor.
@@ -1061,59 +1040,7 @@ bool SCD4x::measureSingleShotRHTOnly(void)
   return (success);
 }
 
-// Determine Sensor type from the serial number
-bool SCD4x::determineSensorType(scd4x_sensor_type_e *sensorType, char *serialNumber)
-{
-  bool success = true;
-
-  if(strlen(serialNumber) != 12)
-  {
-    #if SCD4x_ENABLE_DEBUGLOG
-    if (_printDebug == true) 
-    {
-      _debugPort->println(F("SCD40::getSensorType: S/N is not 13 bytes."));
-      _debugPort->print(F("SCD40::getSensorType: Num Bytes: "));
-      _debugPort->println(strlen(serialNumber));
-    }
-    #endif // if SCD4x_ENABLE_DEBUGLOG
-    success = false;
-    return (success);
-  }
-
-  uint16_t serNumInt[3];
-  convertASCIIToHex(serialNumber, serNumInt);
-
-  #if SCD4x_ENABLE_DEBUGLOG
-  if (_printDebug == true) 
-  {
-    _debugPort->print("SCD40::getSensorType: Word 1: ");
-    _debugPort->println(serNumInt[0], HEX);
-    _debugPort->print("SCD40::getSensorType: Word 2: ");
-    _debugPort->println(serNumInt[1], HEX);
-    _debugPort->print("SCD40::getSensorType: Word 3: ");
-    _debugPort->println(serNumInt[2], HEX);
-  }
-  #endif // if SCD4x_ENABLE_DEBUGLOG
-
-  *sensorType = extractMaskedSensorType(serNumInt);
-
-  if (*sensorType == SCD4x_SENSOR_INVALID)
-  {
-    #if SCD4x_ENABLE_DEBUGLOG
-    if (_printDebug == true)
-    {
-      _debugPort->println("SCD40::getSensorType: Invalid Sensor Type Determined.");
-    }
-    #endif // if SCD4x_ENABLE_DEBUGLOG
-    *sensorType = SCD4x_SENSOR_SCD40; // Pick a default so we don't break things.
-    success = false;
-    return (success);
-  }
-
-  return (success);
-}
-
-scd4x_sensor_type_e SCD4x::getSensorType()
+scd4x_sensor_type_e SCD4x::getSensorType(void)
 {
   return _sensorType;
 }
@@ -1123,71 +1050,80 @@ void SCD4x::setSensorType(scd4x_sensor_type_e sensorType)
   _sensorType = sensorType;
 }
 
-// Extract the Sensor type (SCD40 vs SCD41) from the Serial Number of the connected device.
-scd4x_sensor_type_e SCD4x::extractMaskedSensorType(uint16_t *serialNumberArray)
+bool SCD4x::getFeatureSetVersion(scd4x_sensor_type_e* sensorType)
 {
-  // Of the 48-bit serial number, the Type is identified by bits 24-37
-  // 0bxxxx'xxxx'xx11'1111'1111'1111'xxxx'xxxx'xxxx'xxxx'xxxx'xxxx
-  uint16_t masks[] = {0x003F, 0xFF00}; 
-
-  uint16_t maskedValues[2];
-  uint16_t combinedValue = 0;
-
-  for (int i = 0; i < 2; i++) {
-    maskedValues[i] = serialNumberArray[i] & masks[i];
+  if (periodicMeasurementsAreRunning)
+  {
     #if SCD4x_ENABLE_DEBUGLOG
-    if(_printDebug == true) {
-      _debugPort->print("SCD40::extractMaskedSensorType: i: ");
-      _debugPort->println(i);
-      _debugPort->print("SCD40::extractMaskedSensorType: serialNumberArray[i]: ");
-      _debugPort->println(serialNumberArray[i], HEX);
-      _debugPort->print("SCD40::extractMaskedSensorType: masks[i]: ");
-      _debugPort->println(masks[i], HEX);
-      _debugPort->print("SCD40::extractMaskedSensorType: maskedValues[i]: ");
-      _debugPort->println(maskedValues[i], HEX);
+    if (_printDebug == true)
+    {
+      _debugPort->println(F("SCD4x::getFeatureSetVersion: periodic measurements are running. Aborting..."));
     }
-    #endif // if SCD4x_ENABLE_DEBUGLOG
+    #endif // SCD4x_ENABLE_DEBUGLOG
+    return (false);
   }
 
-  combinedValue = (maskedValues[0] << 8) | (maskedValues[1] >> 8);
+  uint16_t featureSet;
+
+  bool success = readRegister(SCD4x_COMMAND_GET_FEATURE_SET_VERSION, &featureSet, 1);
 
   #if SCD4x_ENABLE_DEBUGLOG
-  if (_printDebug == true) 
+  if (_printDebug == true)
   {
-    _debugPort->print("SCD40::extractMaskedSensorType: Combined Value: ");
-    _debugPort->println(combinedValue, HEX);
+    _debugPort->print(F("SCD4x::getFeatureSetVersion: Read value: 0x"));
+    _debugPort->println(featureSet, HEX);
   }
-  #endif // if SCD4x_ENABLE_DEBUGLOG
+  #endif // SCD4x_ENABLE_DEBUGLOG
+
+  uint8_t typeOfSensor = ((featureSet & 0x1000) >> 12);
+
+  #if SCD4x_ENABLE_DEBUGLOG
+  if (_printDebug == true)
+  {
+    _debugPort->print(F("SCD4x::getFeatureSetVersion: Type read: 0x"));
+    _debugPort->println(typeOfSensor, HEX);
+  }
+  #endif // SCD4x_ENABLE_DEBUGLOG
 
-  if (combinedValue == 0x376F)
+  if (typeOfSensor == 0)
   {
     #if SCD4x_ENABLE_DEBUGLOG
     if (_printDebug == true) 
     {
-      _debugPort->println("SCD40::extractMaskedSensorType: Picked SCD41");
+      _debugPort->println(F("SCD4x::getFeatureSetVersion: Picked SCD40"));
     }
     #endif // if SCD4x_ENABLE_DEBUGLOG
-    return SCD4x_SENSOR_SCD41;
+    *sensorType = SCD4x_SENSOR_SCD40;
   }
-  else if (combinedValue == 0x2397) 
+  else if (typeOfSensor == 1) 
   {
     #if SCD4x_ENABLE_DEBUGLOG
     if (_printDebug == true) 
     {
-      _debugPort->println("SCD40::extractMaskedSensorType: Picked SCD40");
+      _debugPort->println(F("SCD4x::getFeatureSetVersion: Picked SCD41"));
     }
     #endif // if SCD4x_ENABLE_DEBUGLOG
-    return SCD4x_SENSOR_SCD40;
+    *sensorType = SCD4x_SENSOR_SCD41;
   }
   else 
   {
     #if SCD4x_ENABLE_DEBUGLOG
     if (_printDebug == true) {
-      _debugPort->println("SCD40::extractMaskedSensorType: Something's seriously wrong here...");
+      if(typeOfSensor == 2)
+      {
+        _debugPort->println(F("SCD4x::getFeatureSetVersion: SCD42 is not supported by this library."));
+      }
+      else
+      {
+        _debugPort->println(F("SCD4x::getFeatureSetVersion: Unknown device type."));
+      }
     }
     #endif // if SCD4x_ENABLE_DEBUGLOG
-    return SCD4x_SENSOR_INVALID;
+    *sensorType = SCD4x_SENSOR_INVALID;
+    success = false;
   }
+
+  return (success);
 }
 
 //Sends a command along with arguments and CRC

diff --git a/src/SparkFun_SCD4x_Arduino_Library.h b/src/SparkFun_SCD4x_Arduino_Library.h
@@ -81,6 +81,7 @@
 #define SCD4x_COMMAND_PERFORM_SELF_TEST                       0x3639 // execution time: 10000ms
 #define SCD4x_COMMAND_PERFORM_FACTORY_RESET                   0x3632 // execution time: 1200ms
 #define SCD4x_COMMAND_REINIT                                  0x3646 // execution time: 20ms
+#define SCD4x_COMMAND_GET_FEATURE_SET_VERSION                 0x202F // execution time: 1ms
 
 //Low power single shot - SCD41 only
 #define SCD4x_COMMAND_MEASURE_SINGLE_SHOT                     0x219d // execution time: 5000ms
@@ -184,8 +185,9 @@ class SCD4x
 
   uint8_t computeCRC8(uint8_t data[], uint8_t len);
 
-  bool determineSensorType(scd4x_sensor_type_e *sensorType, char *serialNumber); // Determine sensor type from serial number.
-  scd4x_sensor_type_e getSensorType(); // Get the sensor type stored in the struct.
+  bool getFeatureSetVersion(scd4x_sensor_type_e* sensorType);
+  scd4x_sensor_type_e getSensorType(void); // Get the sensor type stored in the struct.
+  void setSensorType(scd4x_sensor_type_e sensorType); // Set the sensor type for the device.
 
 private:
   //Variables
@@ -215,14 +217,6 @@ class SCD4x
   //Convert serial number digit to ASCII
   char convertHexToASCII(uint8_t digit);
 
-  // Convert serial number string to hex digits.
-  void convertASCIIToHex(const char *hexstr, uint16_t *integers);
-
-  // Helper function to compare the serial number to known IDs.
-  scd4x_sensor_type_e extractMaskedSensorType(uint16_t *serialNumberArray);
-
-  void setSensorType(scd4x_sensor_type_e sensorType); // Set the sensor type for the device.
-
   #if SCD4x_ENABLE_DEBUGLOG
   //Debug
   Stream *_debugPort;          //The stream to send debug messages to if enabled. Usually Serial.