add getSerialNumber (#46)

- add getSerialNumber, kudos to skunktrading
- add example SHT31_getSerialNumber.ino
- changed defines for commands in static constexpr (.cpp)
- update examples
- update readme.md
- update keywords.txt
- minor edits

* fix build

* fix build

Author: RobTillaart

CHANGELOG.md

@@ -6,6 +6,15 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.5.2] - 2025-05-10
+- add getSerialNumber, kudos to skunktrading
+- add example SHT31_getSerialNumber.ino
+- changed defines for commands in static constexpr (.cpp)
+- update examples
+- update readme.md
+- update keywords.txt
+- minor edits
+
 ## [0.5.1] - 2025-04-28
 - add **clearStatus()**, kudos to Elbandi
 - update readme.md

README.md

@@ -148,18 +148,19 @@ you've performed a new reading.
 Be sure to clear the error flag by calling **getError()** before calling 
 any command as the error flag could be from a previous command.
 
-|  Error  |  Symbolic                   |  Description                   |
-|:-------:|:----------------------------|:-------------------------------|
-|  0x00   |  SHT31_OK                   |  no error                      |
-|  0x81   |  SHT31_ERR_WRITECMD         |  I2C write failed              |
-|  0x82   |  SHT31_ERR_READBYTES        |  I2C read failed               |
-|  0x83   |  SHT31_ERR_HEATER_OFF       |  Could not switch off heater   |
-|  0x84   |  SHT31_ERR_NOT_CONNECT      |  Could not connect             |
-|  0x85   |  SHT31_ERR_CRC_TEMP         |  CRC error in temperature      |
-|  0x86   |  SHT31_ERR_CRC_HUM          |  CRC error in humidity         |
-|  0x87   |  SHT31_ERR_CRC_STATUS       |  CRC error in status field     |
-|  0x88   |  SHT31_ERR_HEATER_COOLDOWN  |  Heater need to cool down      |
-|  0x89   |  SHT31_ERR_HEATER_ON        |  Could not switch on heater    |
+|  Error  |  Symbolic                     |  Description                   |
+|:-------:|:------------------------------|:-------------------------------|
+|  0x00   |  SHT31_OK                     |  no error                      |
+|  0x81   |  SHT31_ERR_WRITECMD           |  I2C write failed              |
+|  0x82   |  SHT31_ERR_READBYTES          |  I2C read failed               |
+|  0x83   |  SHT31_ERR_HEATER_OFF         |  Could not switch off heater   |
+|  0x84   |  SHT31_ERR_NOT_CONNECT        |  Could not connect             |
+|  0x85   |  SHT31_ERR_CRC_TEMP           |  CRC error in temperature      |
+|  0x86   |  SHT31_ERR_CRC_HUM            |  CRC error in humidity         |
+|  0x87   |  SHT31_ERR_CRC_STATUS         |  CRC error in status field     |
+|  0x88   |  SHT31_ERR_HEATER_COOLDOWN    |  Heater need to cool down      |
+|  0x89   |  SHT31_ERR_HEATER_ON          |  Could not switch on heater    |
+|  0x8A   |  SHT31_ERR_SERIAL_NUMBER_CRC  |  Could not switch on heater    |
 
 
 ### Heater interface
@@ -223,6 +224,12 @@ Returns false if reading fails or in case of a CRC failure.
 **bool clearStatus()** clears 15, 11, 10 and 4.
 
 
+### GetSerial
+
+- **bool getSerialNumber(uint32_t &serial, bool fast = true)** fast == true, => no CRC check
+fast == false, => do CRC check. 
+
+
 ## Future
 
 #### Must
@@ -240,6 +247,8 @@ Returns false if reading fails or in case of a CRC failure.
 #### Could
 
 - move code from .h to .cpp
+- param fast in getSerialNumber => skipCRC?
+
 
 #### Wont
 

SHT31.cpp

@@ -12,25 +12,26 @@
 
 
 //  SUPPORTED COMMANDS - single shot mode only
-#define SHT31_READ_STATUS       0xF32D
-#define SHT31_CLEAR_STATUS      0x3041
+static constexpr uint16_t SHT31_READ_STATUS       = 0xF32D;
+static constexpr uint16_t SHT31_CLEAR_STATUS      = 0x3041;
 
-#define SHT31_SOFT_RESET        0x30A2
-#define SHT31_HARD_RESET        0x0006
+static constexpr uint16_t SHT31_SOFT_RESET        = 0x30A2;
+static constexpr uint16_t SHT31_HARD_RESET        = 0x0006;
 
-#define SHT31_MEASUREMENT_FAST  0x2416     //  page 10 datasheet
-#define SHT31_MEASUREMENT_SLOW  0x2400     //  no clock stretching
+static constexpr uint16_t SHT31_MEASUREMENT_FAST  = 0x2416;     //  page 10 datasheet
+static constexpr uint16_t SHT31_MEASUREMENT_SLOW  = 0x2400;     //  no clock stretching
 
-#define SHT31_HEAT_ON           0x306D
-#define SHT31_HEAT_OFF          0x3066
-#define SHT31_HEATER_TIMEOUT    180000UL   //  milliseconds
+static constexpr uint16_t SHT31_HEAT_ON           = 0x306D;
+static constexpr uint16_t SHT31_HEAT_OFF          = 0x3066;
+static constexpr uint32_t SHT31_HEATER_TIMEOUT    = 180000UL;   //  milliseconds
+
+static constexpr uint16_t SHT31_GET_SERIAL_NUMBER = 0x3682;     //  no clock stretching
 
-static constexpr uint16_t SHT31_GET_SERIAL_NUMBER = 0x3682;		//  no clock stretching
 
 SHT31::SHT31(uint8_t address, TwoWire *wire)
 {
-  _wire           = wire;
   _address        = address;
+  _wire           = wire;
   _lastRead       = 0;
   _rawTemperature = 0;
   _rawHumidity    = 0;
@@ -132,7 +133,6 @@ uint16_t SHT31::readStatus()
     _error = SHT31_ERR_CRC_STATUS;
     return 0xFFFF;
   }
-
   return (uint16_t) (status[0] << 8) + status[1];
 }
 
@@ -151,6 +151,7 @@ bool SHT31::clearStatus()
   return true;
 }
 
+
 bool SHT31::reset(bool hard)
 {
   bool b = writeCmd(hard ? SHT31_HARD_RESET : SHT31_SOFT_RESET);
@@ -225,7 +226,7 @@ bool SHT31::isHeaterOn()
 
 /////////////////////////////////////////////////////////////////
 //
-//  ASYNC
+//  ASYNCHRONUOUS INTERFACE
 //
 bool SHT31::requestData()
 {
@@ -270,18 +271,22 @@ bool SHT31::readData(bool fast)
   _rawHumidity    = (buffer[3] << 8) + buffer[4];
 
   _lastRead = millis();
-
   return true;
 }
 
 
+/////////////////////////////////////////////////////////////////
+//
+//  MISC
+//
 int SHT31::getError()
 {
   int rv = _error;
   _error = SHT31_OK;
   return rv;
 }
 
+
 /**
  * See https://sensirion.com/media/documents/E5762713/63D103C2/Sensirion_electronic_identification_code_SHT3x.pdf
  */
@@ -305,10 +310,17 @@ bool SHT31::getSerialNumber(uint32_t &serial, bool fast) {
       return false;
       }
   }
-  serial = (buffer[0] << 24) | (buffer[1] << 16) | (buffer[3] << 8) | buffer[4];
+  serial = buffer[0];
+  serial <<= 8;
+  serial += buffer[1];
+  serial <<= 8;
+  serial += buffer[3];
+  serial <<= 8;
+  serial += buffer[4];
   return true;
 }
 
+
 /////////////////////////////////////////////////////////////////
 //
 //  PROTECTED
@@ -342,6 +354,7 @@ bool SHT31::writeCmd(uint16_t cmd)
     _error = SHT31_ERR_WRITECMD;
     return false;
   }
+  _error = SHT31_OK;
   return true;
 }
 
@@ -355,6 +368,7 @@ bool SHT31::readBytes(uint8_t n, uint8_t *val)
     {
       val[i] = _wire->read();
     }
+    _error = SHT31_OK;
     return true;
   }
   _error = SHT31_ERR_READBYTES;

SHT31.h

@@ -2,7 +2,7 @@
 //
 //    FILE: SHT31.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.5.1
+// VERSION: 0.5.2
 //    DATE: 2019-02-08
 // PURPOSE: Arduino library for the SHT31 temperature and humidity sensor
 //          https://www.adafruit.com/product/2857
@@ -13,7 +13,7 @@
 #include "Wire.h"
 
 
-#define SHT31_LIB_VERSION             (F("0.5.1"))
+#define SHT31_LIB_VERSION             (F("0.5.2"))
 
 #ifndef SHT_DEFAULT_ADDRESS
 #define SHT_DEFAULT_ADDRESS           0x44
@@ -39,7 +39,8 @@
 #define SHT31_ERR_CRC_STATUS          0x87
 #define SHT31_ERR_HEATER_COOLDOWN     0x88
 #define SHT31_ERR_HEATER_ON           0x89
-#define SHT31_ERR_SERIAL_NUMBER_CRC		0x8A
+#define SHT31_ERR_SERIAL_NUMBER_CRC   0x8A
+
 
 class SHT31
 {
@@ -90,8 +91,11 @@ class SHT31
   bool dataReady();
   bool readData(bool fast = true);
 
+  //  MISC
   int getError();  //  clears error flag
-  bool getSerialNumber(uint32_t &serial, bool fast=true);
+  //  fast == true, => skips CRC check
+  bool getSerialNumber(uint32_t &serial, bool fast = true);
+
 
 protected:
   uint8_t  _address;

examples/SHT31_I2Cspeed/SHT31_I2Cspeed.ino

@@ -18,10 +18,13 @@ SHT31 sht(SHT31_ADDRESS);
 
 void setup()
 {
+  //  while(!Serial);  //  uncomment if needed
   Serial.begin(115200);
+  Serial.println();
   Serial.println(__FILE__);
   Serial.print("SHT31_LIB_VERSION: \t");
   Serial.println(SHT31_LIB_VERSION);
+  Serial.println();
 
   Wire.begin();
   Wire.setClock(100000);

examples/SHT31_async/SHT31_async.ino

@@ -19,10 +19,13 @@ SHT31 sht;  //  use default address and Wire
 
 void setup()
 {
+  //  while(!Serial);  //  uncomment if needed
   Serial.begin(115200);
+  Serial.println();
   Serial.println(__FILE__);
   Serial.print("SHT31_LIB_VERSION: \t");
   Serial.println(SHT31_LIB_VERSION);
+  Serial.println();
 
   Wire.begin();
   Wire.setClock(100000);
@@ -31,7 +34,7 @@ void setup()
   uint16_t stat = sht.readStatus();
   Serial.print(stat, HEX);
   Serial.println();
-  
+
   sht.requestData();
   cnt = 0;
 }

examples/SHT31_demo/SHT31_demo.ino

@@ -18,10 +18,13 @@ SHT31 sht;
 
 void setup()
 {
+  //  while(!Serial);  //  uncomment if needed
   Serial.begin(115200);
+  Serial.println();
   Serial.println(__FILE__);
   Serial.print("SHT31_LIB_VERSION: \t");
   Serial.println(SHT31_LIB_VERSION);
+  Serial.println();
 
   Wire.begin();
   Wire.setClock(100000);

examples/SHT31_demo_plotter/SHT31_demo_plotter.ino

@@ -1,7 +1,7 @@
 //
 //    FILE: SHT31_demo_plotter.ino
 //  AUTHOR: Rob Tillaart
-// PURPOSE: demo
+// PURPOSE: demo for plotter
 //     URL: https://github.com/RobTillaart/SHT31
 
 
@@ -18,11 +18,13 @@ SHT31 sht;
 
 void setup()
 {
+  //  while(!Serial);  //  uncomment if needed
   Serial.begin(115200);
+  //  Serial.println();
   //  Serial.println(__FILE__);
   //  Serial.print("SHT31_LIB_VERSION: \t");
   //  Serial.println(SHT31_LIB_VERSION);
-
+  //  Serial.println();
 
   Wire.begin();
   Wire.setClock(100000);

examples/SHT31_getSerialNumber/SHT31_getSerialNumber.ino

@@ -0,0 +1,88 @@
+//
+//    FILE: SHT31_getSerialNumber.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: demo Serial Number
+//     URL: https://github.com/RobTillaart/SHT31
+
+
+#include "Wire.h"
+#include "SHT31.h"
+
+#define SHT31_ADDRESS   0x44
+
+uint32_t start;
+uint32_t stop;
+
+SHT31 sht(SHT31_ADDRESS);  //  uses explicit address
+
+
+void setup()
+{
+  //  while(!Serial);  //  uncomment if needed
+  Serial.begin(115200);
+  Serial.println();
+  Serial.println(__FILE__);
+  Serial.print("SHT31_LIB_VERSION: \t");
+  Serial.println(SHT31_LIB_VERSION);
+  Serial.println();
+
+  Wire.begin();
+  Wire.setClock(100000);
+  sht.begin();
+
+  uint16_t stat = sht.readStatus();
+  Serial.print("STATUS:\t");
+  Serial.print(stat, HEX);
+  Serial.println();
+
+  delay(100);
+
+  uint32_t sn = 0;
+  bool b;
+
+  start = micros();
+  b = sht.getSerialNumber(sn, true);
+  stop = micros();
+  Serial.println("FAST:\ttrue");
+  Serial.print("TIME:\t");
+  Serial.println(stop - start);
+  if (b)
+  {
+    Serial.print("SN:\t");
+    Serial.println(sn);
+  }
+  else
+  {
+    Serial.print("ERROR:\t");
+    Serial.println(sht.getError(), HEX);
+  }
+  delay(100);
+
+  start = micros();
+  b = sht.getSerialNumber(sn, false);
+  stop = micros();
+  Serial.println("FAST:\tfalse");
+  Serial.print("TIME:\t");
+  Serial.println(stop - start);
+  if (b)
+  {
+    Serial.print("SN:\t");
+    Serial.println(sn);
+  }
+  else
+  {
+    Serial.print("ERROR:\t");
+    Serial.println(sht.getError(), HEX);
+  }
+
+  Serial.println("\ndone...");
+}
+
+
+void loop()
+{
+
+}
+
+
+//  -- END OF FILE --