0.2.0 DS18B20_INT

libraries/DS18B20_INT/DS18B20_INT.cpp

@@ -1,10 +1,11 @@
 //
 //    FILE: DS18B20_INT.cpp
 //  AUTHOR: Rob.Tillaart@gmail.com
-// VERSION: 0.1.7
+// VERSION: 0.2.0
 //    DATE: 2017-07-25
 // PUPROSE: library for DS18B20 temperature sensor - integer only.
 //     URL: https://github.com/RobTillaart/DS18B20_INT
+//          https://github.com/RobTillaart/DS18B20_RT
 //
 //  HISTORY:
 //  0.1.0   2017-07-25  initial version
@@ -15,6 +16,8 @@
 //  0.1.5   2021-06-16  add retries parameter to begin()
 //  0.1.6   2021-10-03  add dependency + fix build-CI
 //  0.1.7   2021-12-17  update library.json, license, minor edits
+//  0.2.0   2022-06-23  fix #10 getTempCentiC() (thanks negroKiordi)
+//                      fix reading sensor
 
 
 #include "DS18B20_INT.h"
@@ -26,13 +29,17 @@
 
 
 // Device resolution
-#define TEMP_9_BIT              0x1F //  9 bit
+#define TEMP_9_BIT              0x1F    //  9 bit
+#define TEMP_10_BIT             0x3F    // 10 bit
+#define TEMP_11_BIT             0x5F    // 11 bit
+#define TEMP_12_BIT             0x7F    // 12 bit
 
 
 DS18B20_INT::DS18B20_INT(OneWire* ow)
 {
-  _oneWire = ow;
+  _oneWire      = ow;
   _addressFound = false;
+  _resolution   = TEMP_9_BIT;
 }
 
 
@@ -57,7 +64,7 @@ bool DS18B20_INT::begin(uint8_t retries)
     // two dummy values for LOW & HIGH ALARM
     _oneWire->write(0);
     _oneWire->write(100);
-    _oneWire->write(TEMP_9_BIT);     // lowest as we do only integer math.
+    _oneWire->write(_resolution);     // lowest as we do only integer math.
     _oneWire->reset();
   }
   return _addressFound;
@@ -80,12 +87,7 @@ bool DS18B20_INT::isConversionComplete(void)
 
 int16_t DS18B20_INT::getTempC(void)
 {
-  _oneWire->reset();
+  int16_t rawTemperature = _readRaw();
-  _oneWire->select(_deviceAddress);
-  _oneWire->write(READSCRATCH);
-  int16_t rawTemperature = ((int16_t)_oneWire->read()) << 8;
-  rawTemperature |= _oneWire->read();
-  _oneWire->reset();
   rawTemperature >>= 4;
   if (rawTemperature < -55) return DEVICE_DISCONNECTED;
   return rawTemperature;
@@ -105,5 +107,66 @@ bool  DS18B20_INT::getAddress(uint8_t* buf)
 }
 
 
+void DS18B20_INT::setResolution(uint8_t bits)
+{
+  uint8_t newRes = 0;
+  switch (bits)
+  {
+    case 12: newRes = TEMP_12_BIT;  break;
+    case 11: newRes = TEMP_11_BIT;  break;
+    case 10: newRes = TEMP_10_BIT;  break;
+    default: newRes = TEMP_9_BIT;   break;
+  }
+  if (newRes != _resolution)
+  {
+    _resolution = newRes;
+    begin();
+  }
+}
+
+
+uint8_t DS18B20_INT::getResolution()
+{
+  switch (_resolution)
+  {
+    case TEMP_12_BIT: return 12;
+    case TEMP_11_BIT: return 11;
+    case TEMP_10_BIT: return 10;
+    case TEMP_9_BIT:  return 9;
+  }
+  return 0;
+}
+
+
+int16_t DS18B20_INT::getTempCentiC(void)
+{
+  int16_t rawTemperature = _readRaw();
+  //  rawTemperature = rawTemperature * 100 / 16;
+  rawTemperature *= 25;
+  rawTemperature >>= 2;
+  //  use at own risk.
+  //  if (rawTemperature < -5500) return DEVICE_DISCONNECTED * 100;
+  return rawTemperature;
+}
+
+
+//////////////////////////////////////////////////
+//
+//  PRIVATE
+//
+int16_t DS18B20_INT::_readRaw(void)
+{
+  _oneWire->reset();
+  _oneWire->select(_deviceAddress);
+  _oneWire->write(READSCRATCH);
+  int16_t rawTemperature = ((int16_t)_oneWire->read());
+  rawTemperature |= _oneWire->read() << 8;
+  _oneWire->reset();
+  return rawTemperature;
+}
+
+
+
+
 //  -- END OF FILE --
 

libraries/DS18B20_INT/DS18B20_INT.h

@@ -2,11 +2,12 @@
 //
 //    FILE: DS18B20_INT.h
 //  AUTHOR: Rob.Tillaart@gmail.com
-// VERSION: 0.1.7
+// VERSION: 0.2.0
 //    DATE: 2017-07-25
 // PUPROSE: Minimalistic library for DS18B20 temperature sensor
 //          uses only integer math (no float to minimize footprint)
 //     URL: https://github.com/RobTillaart/DS18B20_INT
+//          https://github.com/RobTillaart/DS18B20_RT
 
 //
 //  BOTTOM VIEW
@@ -20,7 +21,7 @@
 //
 
 
-#define DS18B20_INT_LIB_VERSION       (F("0.1.7"))
+#define DS18B20_INT_LIB_VERSION       (F("0.2.0"))
 
 #include "Arduino.h"
 #include "OneWire.h"
@@ -41,10 +42,18 @@ public:
   bool      isConversionComplete(void);
   bool      getAddress(uint8_t* buf);
 
+  void      setResolution(uint8_t bits = 9);
+  uint8_t   getResolution();
+  int16_t   getTempCentiC(void);
+
+
 private:
   DeviceAddress _deviceAddress;
   OneWire*      _oneWire;
   bool          _addressFound;
+
+  uint8_t       _resolution;
+  int16_t       _readRaw();
 };
 
 

libraries/DS18B20_INT/README.md

@@ -24,6 +24,8 @@ I'm a great fan of the above library however some time ago I needed to strip it
 to save a few dozen bytes. I reworked that minimalistic version into a library and I 
 added a number of Arduino examples to help you get started.
 
+This library is also related to - https://github.com/RobTillaart/DS18B20_RT
+
 
 ## Interface
 
@@ -37,10 +39,29 @@ returns true if all is OK. there will be a number of retries to connect, default
 - **void requestTemperatures()** trigger temperature conversion.
 - **bool isConversionComplete()** check if conversion is complete.
 - **int16_t getTempC()** returns temperature in whole degrees only. -55..125  
--127 = DEVICE_DISCONNECTED
+or  -127 = DEVICE_DISCONNECTED
 - **bool getAddress()** returns true if the sensor is configured (available).
 
 
+### CentiC part
+
+The following functions are experimental since 0.2.0
+They allow to use a higher resolution while not using floats. 
+This keeps the library small.
+
+- **void setResolution(uint8_t bits = 9)** sets the internal resolution to 9, 10, 11 or 12 bits. 
+Other numbers will be mapped on 9. 
+This will affect the conversion time for a measurement.
+Internally it will call **begin()** to set the new resolution if needed.
+- **void getResolution()** returns the bits set, default 9.
+Convenience function.
+- **getTempCentiC(void)** returns the measured temperature times 100. -5500..12500
+So 10.62°C will be returned as 1062.
+
+**Warning** The DEVICE_DISCONNECTED is not tested for, but is commented in the code. 
+Use at own risk.
+
+
 ## Operation
 
 This library supports only one DS18B20 per Arduino/ MCU pin.
@@ -60,8 +81,6 @@ This library supports only one DS18B20 per Arduino/ MCU pin.
 Connect a pull-up resistor 4.7 KOhm between pin3 and pin2. 
 When the wires are longer this resistor needs to be smaller.
 
-Check examples.
-
 
 ### Pull up resistor
 
@@ -78,7 +97,7 @@ Note: thicker wires require smaller resistors (typically 1 step in E12 series)
 | 100cm (3'4")  |     3K3     |    2K2     | 
 | 200cm (6'8")  |     2K2     |    1K0     | 
 | 500cm (16'8") |     1K0     |    \*      |  
-| longer        |       *     |    \*      |
+| longer        |     \*      |    \*      |
 
 \* = no info, smaller 
 
@@ -93,4 +112,7 @@ and all people who contributed to that lib.
 
 - add examples
   - a multi sensor == multiple pins, no bus
+- add rounding for **getTempC()**.
+  - now it truncates, so it can be 0.5°C off.
+  - add "0.5" to raw and truncate
 

libraries/DS18B20_INT/examples/DS18B20_INT/DS18B20_INT.ino

@@ -1,7 +1,6 @@
 //
 //    FILE: DS18B20_INT.ino
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.0.1
 // PURPOSE: Minimalistic demo
 
 
@@ -43,4 +42,3 @@ void loop()
 
 
 // -- END OF FILE --
-

libraries/DS18B20_INT/examples/DS18B20_INT_getTempCentiC/DS18B20_INT_getTempCentiC.ino

@@ -0,0 +1,46 @@
+//
+//    FILE: DS18B20_INT_getTempCentiC.ino
+//  AUTHOR: Rob Tillaart
+// PURPOSE: Minimalistic demo
+
+
+#include "DS18B20_INT.h"
+
+#define ONE_WIRE_BUS            2
+
+OneWire oneWire(ONE_WIRE_BUS);
+DS18B20_INT sensor(&oneWire);
+
+uint32_t start, stop;
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  sensor.begin();
+  sensor.setResolution(12);
+  Serial.println(sensor.getResolution());
+}
+
+
+void loop()
+{
+  int n = 0;
+  start = millis();
+  sensor.requestTemperatures();
+  while (!sensor.isConversionComplete()) n++;
+  int t = sensor.getTempCentiC();
+  stop = millis();
+
+  Serial.print(stop - start);
+  Serial.print("\t");
+  Serial.print(n);
+  Serial.print("\t");
+  Serial.println(t);
+  Serial.println();
+  delay(1000);
+}
+
+
+// -- END OF FILE --

libraries/DS18B20_INT/keywords.txt

@@ -11,6 +11,10 @@ requestTemperatures	KEYWORD2
 isConversionComplete	KEYWORD2
 getAddress	KEYWORD2
 
+setResolution	KEYWORD2
+getResolution	KEYWORD2
+getTempCentiC	KEYWORD2
+
 
 # Constants (LITERAL1)
 DS18B20_INT_LIB_VERSION	LITERAL1

libraries/DS18B20_INT/library.json

@@ -23,7 +23,7 @@
       "version": "^2.3.5"
     }
   ],
-  "version": "0.1.7",
+  "version": "0.2.0",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*",

libraries/DS18B20_INT/library.properties

@@ -1,5 +1,5 @@
 name=DS18B20_int
-version=0.1.7
+version=0.2.0
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=Library for DS18B20 restricted to a single sensor per pin.