read out serial as 64 bit integer

instead of raw uint16 array

Author: LeonieFierz

examples/exampleScd41SingleShot/exampleScd41SingleShot.ino

@@ -51,12 +51,10 @@ SensirionI2cScd4x sensor;
 static char errorMessage[64];
 static int16_t error;
 
-void print_ushort_array(uint16_t* array, uint16_t len) {
-    uint16_t i = 0;
+void PrintUint64(uint64_t& value) {
     Serial.print("0x");
-    for (; i < len; i++) {
-        Serial.print(array[i], HEX);
-    }
+    Serial.print((uint32_t)(value >> 32), HEX);
+    Serial.print((uint32_t)(value & 0xFFFFFFFF), HEX);
 }
 
 void setup() {
@@ -68,7 +66,7 @@ void setup() {
     Wire.begin();
     sensor.begin(Wire, SCD41_I2C_ADDR_62);
 
-    uint16_t serialNumber[3] = {0};
+    uint64_t serialNumber = 0;
     delay(30);
     // Ensure sensor is in clean state
     error = sensor.wakeUp();
@@ -90,15 +88,15 @@ void setup() {
         Serial.println(errorMessage);
     }
     // Read out information about the sensor
-    error = sensor.getSerialNumber(serialNumber, 3);
+    error = sensor.getSerialNumber(serialNumber);
     if (error != NO_ERROR) {
         Serial.print("Error trying to execute getSerialNumber(): ");
         errorToString(error, errorMessage, sizeof errorMessage);
         Serial.println(errorMessage);
         return;
     }
-    Serial.print("serial number: ");
-    print_ushort_array(serialNumber, 3);
+    Serial.print("serial number: 0x");
+    PrintUint64(serialNumber);
     Serial.println();
     //
     // If temperature offset and/or sensor altitude compensation

examples/exampleUsage/exampleUsage.ino

@@ -51,12 +51,10 @@ SensirionI2cScd4x sensor;
 static char errorMessage[64];
 static int16_t error;
 
-void print_ushort_array(uint16_t* array, uint16_t len) {
-    uint16_t i = 0;
+void PrintUint64(uint64_t& value) {
     Serial.print("0x");
-    for (; i < len; i++) {
-        Serial.print(array[i], HEX);
-    }
+    Serial.print((uint32_t)(value >> 32), HEX);
+    Serial.print((uint32_t)(value & 0xFFFFFFFF), HEX);
 }
 
 void setup() {
@@ -68,7 +66,7 @@ void setup() {
     Wire.begin();
     sensor.begin(Wire, SCD41_I2C_ADDR_62);
 
-    uint16_t serialNumber[3] = {0};
+    uint64_t serialNumber = 0;
     delay(30);
     // Ensure sensor is in clean state
     error = sensor.wakeUp();
@@ -90,15 +88,15 @@ void setup() {
         Serial.println(errorMessage);
     }
     // Read out information about the sensor
-    error = sensor.getSerialNumber(serialNumber, 3);
+    error = sensor.getSerialNumber(serialNumber);
     if (error != NO_ERROR) {
         Serial.print("Error trying to execute getSerialNumber(): ");
         errorToString(error, errorMessage, sizeof errorMessage);
         Serial.println(errorMessage);
         return;
     }
     Serial.print("serial number: ");
-    print_ushort_array(serialNumber, 3);
+    PrintUint64(serialNumber);
     Serial.println();
     //
     // If temperature offset and/or sensor altitude compensation

src/SensirionI2cScd4x.cpp

@@ -538,8 +538,7 @@ int16_t SensirionI2cScd4x::persistSettings() {
     return localError;
 }
 
-int16_t SensirionI2cScd4x::getSerialNumber(uint16_t serialNumber[],
-                                           uint16_t serialNumberSize) {
+int16_t SensirionI2cScd4x::getSerialNumber(uint64_t& serialNumber) {
     int16_t localError = NO_ERROR;
     uint8_t* buffer_ptr = communication_buffer;
     SensirionI2CTxFrame txFrame =
@@ -556,8 +555,7 @@ int16_t SensirionI2cScd4x::getSerialNumber(uint16_t serialNumber[],
     if (localError != NO_ERROR) {
         return localError;
     }
-    localError |=
-        rxFrame.getBytes((uint8_t*)serialNumber, (serialNumberSize * 2));
+    localError |= rxFrame.getInteger(reinterpret_cast<uint8_t*>(&serialNumber), LongInteger, 6);
     return localError;
 }
 

src/SensirionI2cScd4x.h

@@ -595,15 +595,16 @@ class SensirionI2cScd4x {
      * verify the presence of the sensor. The get_serial_number command returns
      * 3 words, and every word is followed by an 8-bit CRC checksum. Together,
      * the 3 words constitute a unique serial number with a length of 48 bits
-     * (in big endian format).
+     * (in big endian format). This method takes care of converting the serial
+     * number from the 3 words to an 64 bit unsigned integer.
      *
-     * @param[out] serialNumber 48-bit unique serial number of the sensor.
+     * @param[out] serialNumber of the sensor as integer.
      *
      * @note This command is only available in idle mode.
      *
      * @return error_code 0 on success, an error code otherwise.
      */
-    int16_t getSerialNumber(uint16_t serialNumber[], uint16_t serialNumberSize);
+    int16_t getSerialNumber(uint64_t& serialNumber);
 
     /**
      * @brief Perform self test to assess sensor functionality and power supply.