0.5.2 SHT2x

Author: RobTillaart

libraries/SHT2x/CHANGELOG.md

@@ -6,6 +6,10 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.5.2] - 2025-06-14
+- PR #34 - revert status checking
+- improve some error handling
+
 ## [0.5.1] - 2025-05-27
 - PR #32 - update readme.md, comments (Kudos to morfeus02)
 - add 2 examples

libraries/SHT2x/README.md

@@ -17,7 +17,7 @@ Arduino library for the SHT2x, HTU2x and Si70xx temperature and humidity sensors
 ## Description
 
 This library is not tested extensively yet.
-It works for the Si7021 incl. the asynchronous interface.
+It works for the Si7021 including the asynchronous interface.
 It should work for SHT20, SHT21 and SHT25 but these are not tested yet.
 The SHT2x family of sensors should work up to 400 KHz I2C.
 
@@ -102,8 +102,8 @@ These functions are used for synchronous (blocking) reads of temperature and hum
 - **bool read()**: Reads both temperature and humidity from the sensor. This is a blocking call; program execution will pause until the readings are complete.
 - **float getTemperature()**: Returns the temperature in degrees Celsius (°C) based on the latest raw data acquired by `read()`.
 - **float getHumidity()**: Returns the relative humidity in percent (%) based on the latest raw data acquired by `read()`.
-- **uint16_t getRawTemperature()**: Returns the raw, uncalibrated 16-bit integer value for temperature directly from the sensor, as acquired by `read()`.
-- **uint16_t getRawHumidity()**: Returns the raw, uncalibrated 16-bit integer value for humidity directly from the sensor, as acquired by `read()`.
+- **uint16_t getRawTemperature()**: Returns the raw, not calibrated 16-bit integer value for temperature directly from the sensor, as acquired by `read()`.
+- **uint16_t getRawHumidity()**: Returns the raw, not calibrated 16-bit integer value for humidity directly from the sensor, as acquired by `read()`.
 
 **Note on `read()` and data retrieval:**
 The `getTemperature()` and `getHumidity()` functions recalculate values from raw data on every call. If performance is critical, cache these values in your code after a `read()` instead of calling them repeatedly. Raw values are useful for minimizing storage or communication overhead.
@@ -138,11 +138,12 @@ The asynchronous interface allows you to initiate a temperature or humidity read
 - **`uint32_t lastRequest()`**: Returns the timestamp (in milliseconds, based on `millis()`) of when the last asynchronous request (`requestTemperature()` or `requestHumidity()`) was made. This can be useful for implementing timeouts for asynchronous operations.
 - **`uint8_t getRequestType()`**: Returns the type of the currently pending or last completed asynchronous request. This helps in determining what kind of data was requested or is ready. The possible return values are:
 
-| Value  | Symbolic              | Description                   |
-|:------:|:----------------------|:------------------------------|
+| Value  | Symbolic                |  Description  |
+|:------:|:------------------------|:--------------|
 | 0x00   | `SHT2x_REQ_NONE`        | No request pending or last request completed/cleared. |
 | 0x01   | `SHT2x_REQ_TEMPERATURE` | A temperature request is currently pending or was the last one made. |
 | 0x02   | `SHT2x_REQ_HUMIDITY`    | A humidity request is currently pending or was the last one made.    |
+| 0xFF   | `SHT2x_REQ_FAIL`        | A humidity request is currently pending or was the last one made.    |
 
 **Example Snippet (Asynchronous Reading):**
 

libraries/SHT2x/SHT2x.cpp

@@ -1,7 +1,7 @@
 //
 //    FILE: SHT2x.cpp
-//  AUTHOR: Rob Tillaart, Viktor Balint, JensB
-// VERSION: 0.5.1
+//  AUTHOR: Rob Tillaart, Viktor Balint, JensB, morfeus02
+// VERSION: 0.5.2
 //    DATE: 2023-11-25
 // PURPOSE: Arduino library for the SHT2x temperature and humidity sensor
 //     URL: https://github.com/RobTillaart/SHT2x
@@ -24,7 +24,7 @@
 
 
 #define SHT2x_USRREG_RESOLUTION            0x81
-#define SHT2x_USRREG_BATTERY               0x20
+#define SHT2x_USRREG_BATTERY               0x40  //  sht21 datasheet
 #define SHT2x_USRREG_HEATER                0x04
 
 
@@ -97,7 +97,11 @@ bool SHT2x::read()
 //
 bool SHT2x::requestTemperature()
 {
-  writeCmd(SHT2x_GET_TEMPERATURE_NO_HOLD);
+  if (! writeCmd(SHT2x_GET_TEMPERATURE_NO_HOLD))
+  {
+    _requestType = SHT2x_REQ_FAIL;
+    return false;  //  error is registered in writeCmd()
+  }
   _lastRequest = millis();
   _requestType = SHT2x_REQ_TEMPERATURE;
   return true;
@@ -106,7 +110,11 @@ bool SHT2x::requestTemperature()
 
 bool SHT2x::requestHumidity()
 {
-  writeCmd(SHT2x_GET_HUMIDITY_NO_HOLD);
+  if (! writeCmd(SHT2x_GET_HUMIDITY_NO_HOLD))
+  {
+    _requestType = SHT2x_REQ_FAIL;
+    return false;
+  }
   _lastRequest = millis();
   _requestType = SHT2x_REQ_HUMIDITY;
   return true;
@@ -170,19 +178,23 @@ bool SHT2x::readTemperature()
   }
   _rawTemperature  = buffer[0] << 8;
   _rawTemperature += buffer[1];
-  _rawTemperature &= 0xFFFC; // Clear status bits (last two bits)
+  //  Clear status bits (last two bits)
+  _rawTemperature &= 0xFFFC;
 
-  //  clear requestType, marking this async operation as complete
+  //  Clear requestType, marking this async operation as complete
   _requestType = SHT2x_REQ_NONE;
 
-  _status = buffer[1] & 0x03; // Extract status bits
+  //  _status = buffer[1] & 0x02;  //  Extract status bit  (bit 0 not used)
   //  After a temperature read, the status bits should indicate "temperature reading" (0x01).
   //  If not, it implies a read error or unexpected sensor state.
-  if (_status != SHT2x_STATUS_TEMPERATURE)
-  {
-    _error = SHT2x_ERR_READBYTES; // Or a more specific error e.g. SHT2x_ERR_UNEXPECTED_STATUS
-    return false;
-  }
+  //if (_status != SHT2x_STATUS_TEMPERATURE)
+  //{
+  //  _error = SHT2x_ERR_READBYTES; // Or a more specific error e.g. SHT2x_ERR_UNEXPECTED_STATUS
+  //  return false;
+  //}
+
+  _error = SHT2x_OK;
+  _lastRead = millis();
   return true;
 }
 
@@ -209,14 +221,14 @@ bool SHT2x::readHumidity()
   //  clear requestType, marking this async operation as complete
   _requestType = SHT2x_REQ_NONE;
 
-  _status = buffer[1] & 0x03; // Extract status bits
-  //  After a humidity read, the status bits should indicate "humidity reading" (0x02).
+  //  _status = buffer[1] & 0x02; // Extract status bit
+  //  After a humidity read, the status bit should indicate "humidity reading" (0x00).
   //  If not, it implies a read error or unexpected sensor state.
-  if (_status != SHT2x_STATUS_HUMIDITY)
-  {
-    _error = SHT2x_ERR_READBYTES; // Or a more specific error e.g. SHT2x_ERR_UNEXPECTED_STATUS
-    return false;
-  }
+  //if (_status != SHT2x_STATUS_HUMIDITY)
+  //{
+  //  _error = SHT2x_ERR_READBYTES; // Or a more specific error e.g. SHT2x_ERR_UNEXPECTED_STATUS
+  //  return false;
+  //}
 
   _error = SHT2x_OK; // Mark as OK if all checks passed for this specific read
   _lastRead = millis(); // Record time of successful synchronous style read completion
@@ -229,12 +241,16 @@ bool SHT2x::readCachedTemperature()
   if (_error == SHT2x_OK)
   {
     writeCmd(SHT2x_GET_TEMPERATURE_FOR_HUMIDITY);
-    uint8_t buffer[2];
-    if (readBytes(2, (uint8_t*) &buffer[0], 10) == false)
+    uint8_t buffer[3];
+    if (readBytes(3, (uint8_t*) &buffer[0], 10) == false)
     {
       _error = SHT2x_ERR_READBYTES;
       return false;
     }
+    if (crc8(buffer, 2) != buffer[2])
+    {
+      _error = SHT2x_ERR_CRC_TEMP;
+    }
     _rawTemperature  = buffer[0] << 8;
     _rawTemperature += buffer[1];
     _rawTemperature &= 0xFFFC;

libraries/SHT2x/SHT2x.h

@@ -1,7 +1,7 @@
 #pragma once
 //
 //    FILE: SHT2x.h
-//  AUTHOR: Rob Tillaart, Viktor Balint, JensB
+//  AUTHOR: Rob Tillaart, Viktor Balint, JensB, morfeus02
 // VERSION: 0.5.1
 //    DATE: 2023-11-25
 // PURPOSE: Arduino library for the SHT2x temperature and humidity sensor
@@ -18,31 +18,32 @@
 
 //  fields getStatus
 #define SHT2x_STATUS_OPEN_CIRCUIT     0x00
-#define SHT2x_STATUS_TEMPERATURE      0x01
-#define SHT2x_STATUS_HUMIDITY         0x02
+#define SHT2x_STATUS_TEMPERATURE      0x00  //  only bit 1
+#define SHT2x_STATUS_HUMIDITY         0x02  //  only bit 1
 #define SHT2x_STATUS_CLOSED_CIRCUIT   0x03
 
 
 //  Error codes
 //  Error codes are kept somewhat in sync with SHT31 library for consistency where applicable.
-#define SHT2x_OK                      0x00  // Default success value, no error.
-#define SHT2x_ERR_WRITECMD            0x81  // Error during I2C write command.
-#define SHT2x_ERR_READBYTES           0x82  // Error during I2C read bytes.
-#define SHT2x_ERR_HEATER_OFF          0x83  // Failed to switch off the internal heater.
-#define SHT2x_ERR_NOT_CONNECT         0x84  // Sensor not connected or does not acknowledge on the I2C bus.
-#define SHT2x_ERR_CRC_TEMP            0x85  // CRC check failed for the temperature reading.
-#define SHT2x_ERR_CRC_HUM             0x86  // CRC check failed for the humidity reading.
-#define SHT2x_ERR_CRC_STATUS          0x87  // CRC check failed for the status register (currently not actively used for status validation within library).
-#define SHT2x_ERR_HEATER_COOLDOWN     0x88  // Heater is in its mandatory cool-down period and cannot be re-enabled yet.
-#define SHT2x_ERR_HEATER_ON           0x89  // Failed to switch on the internal heater.
-#define SHT2x_ERR_RESOLUTION          0x8A  // Invalid resolution parameter provided (since 0.2.0).
+#define SHT2x_OK                      0x00  //  Default success value, no error.
+#define SHT2x_ERR_WRITECMD            0x81  //  Error during I2C write command.
+#define SHT2x_ERR_READBYTES           0x82  //  Error during I2C read bytes.
+#define SHT2x_ERR_HEATER_OFF          0x83  //  Failed to switch off the internal heater.
+#define SHT2x_ERR_NOT_CONNECT         0x84  //  Sensor not connected or does not acknowledge on the I2C bus.
+#define SHT2x_ERR_CRC_TEMP            0x85  //  CRC check failed for the temperature reading.
+#define SHT2x_ERR_CRC_HUM             0x86  //  CRC check failed for the humidity reading.
+#define SHT2x_ERR_CRC_STATUS          0x87  //  CRC check failed for the status register (currently not actively used for status validation within library).
+#define SHT2x_ERR_HEATER_COOLDOWN     0x88  //  Heater is in its mandatory cool-down period and cannot be re-enabled yet.
+#define SHT2x_ERR_HEATER_ON           0x89  //  Failed to switch on the internal heater.
+#define SHT2x_ERR_RESOLUTION          0x8A  //  Invalid resolution parameter provided (since 0.2.0).
 // Consider adding SHT2x_ERR_UNEXPECTED_STATUS for status check failures in readTemperature/readHumidity.
 // Currently, these failures reuse SHT2x_ERR_READBYTES.
 
 //  Asynchronous request types
-#define SHT2x_REQ_NONE                0x00  // No active asynchronous request.
-#define SHT2x_REQ_TEMPERATURE         0x01  // Asynchronous temperature request is currently active.
-#define SHT2x_REQ_HUMIDITY            0x02  // Asynchronous humidity request is currently active.
+#define SHT2x_REQ_NONE                0x00  //  No active asynchronous request.
+#define SHT2x_REQ_TEMPERATURE         0x01  //  Asynchronous temperature request is currently active.
+#define SHT2x_REQ_HUMIDITY            0x02  //  Asynchronous humidity request is currently active.
+#define SHT2x_REQ_FAIL                0xFF  //  Asynchronous humidity request is currently active.
 
 
 class SHT2x
@@ -62,7 +63,7 @@ class SHT2x
 
   //  Getters for sensor values
   //  These functions return values based on the last successful read() or asynchronous read operation.
-  float    getTemperature();    // Returns the temperature in degrees Celsius (°C).
+  float    getTemperature();    // Returns the temperature in degrees Celsius (°C).
   float    getHumidity();       // Returns the relative humidity in percent (%).
   uint16_t getRawTemperature(); // Returns the raw 16-bit sensor data for temperature.
   uint16_t getRawHumidity();    // Returns the raw 16-bit sensor data for humidity.

libraries/SHT2x/keywords.txt

@@ -79,4 +79,5 @@ SHT2x_STATUS_CLOSED_CIRCUIT	LITERAL1
 SHT2x_REQ_NONE	LITERAL1
 SHT2x_REQ_TEMPERATURE	LITERAL1
 SHT2x_REQ_HUMIDITY	LITERAL1
+SHT2x_REQ_FAIL	LITERAL1
 

libraries/SHT2x/library.json

@@ -24,7 +24,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/SHT2x.git"
   },
-  "version": "0.5.1",
+  "version": "0.5.2",
   "license": "MIT",
   "frameworks": "*",
   "platforms": "*",

libraries/SHT2x/library.properties

@@ -1,5 +1,5 @@
 name=SHT2x
-version=0.5.1
+version=0.5.2
 author=Rob Tillaart <[email protected]>
 maintainer=Rob Tillaart <[email protected]>
 sentence=Arduino library for the I2C SHT20 SHT21 SHT25 series temperature and humidity sensor.

libraries/SHT2x/test/unit_test_001.cpp

@@ -62,7 +62,7 @@ unittest(test_constants_1)
 {
   fprintf(stderr, "fields getStatus\n");
   assertEqual(SHT2x_STATUS_OPEN_CIRCUIT  , 0x00);
-  assertEqual(SHT2x_STATUS_TEMPERATURE   , 0x01);
+  assertEqual(SHT2x_STATUS_TEMPERATURE   , 0x00);
   assertEqual(SHT2x_STATUS_HUMIDITY      , 0x02);
   assertEqual(SHT2x_STATUS_CLOSED_CIRCUIT, 0x03);
 }