add compensation + test ROM in reset (#28)

* add compensation + test ROM in reset

MS5611.cpp

@@ -2,11 +2,13 @@
 //    FILE: MS5611.cpp
 //  AUTHOR: Rob Tillaart
 //          Erni - testing/fixes
-// VERSION: 0.3.7
+// VERSION: 0.3.8
 // PURPOSE: MS5611 Temperature & Humidity library for Arduino
 //     URL: https://github.com/RobTillaart/MS5611
 //
 //  HISTORY:
+//  0.3.8   2022-01-24  reset() returns bool 
+//                      get/setCompensation()
 //  0.3.7   2022-01-22  fix #26 added getPromHash()
 //                      fix #24 default all examples address 0x77
 //  0.3.6   2022-01-15  add setOffset functions; minor refactor;
@@ -74,6 +76,7 @@ MS5611::MS5611(uint8_t deviceAddress)
   _deviceID          = 0;
   _pressureOffset    = 0;
   _temperatureOffset = 0;
+  _compensation      = true;
 }
 
 
@@ -91,8 +94,7 @@ bool MS5611::begin(uint8_t dataPin, uint8_t clockPin, TwoWire * wire)
   }
   if (! isConnected()) return false;
 
-  reset();
-  return true;
+  return reset();
 }
 #endif
 
@@ -104,8 +106,7 @@ bool MS5611::begin(TwoWire * wire)
   _wire->begin();
   if (! isConnected()) return false;
 
-  reset();
-  return true;
+  return reset();
 }
 
 
@@ -120,7 +121,7 @@ bool MS5611::isConnected()
 }
 
 
-void MS5611::reset()
+bool MS5611::reset()
 {
   command(MS5611_CMD_RESET);
   uint32_t start = micros();
@@ -140,6 +141,7 @@ void MS5611::reset()
   C[5] = 256;             // Tref     = C[5] * 2^8
   C[6] = 1.1920928955E-7; // TEMPSENS = C[6] / 2^23
   // read factory calibrations from EEPROM.
+  bool ROM_OK = true;
   for (uint8_t reg = 0; reg < 7; reg++)
   {
     // used indices match datasheet.
@@ -151,7 +153,12 @@ void MS5611::reset()
     _deviceID <<= 4;
     _deviceID ^= tmp;
     // Serial.println(readProm(reg));
+    if (reg > 0)
+    {
+      ROM_OK = ROM_OK && (tmp != 0);
+    }
   }
+  return ROM_OK;
 }
 
 
@@ -171,9 +178,12 @@ int MS5611::read(uint8_t bits)
   uint32_t _D2 = readADC();
   if (_result) return _result;
 
+  // Serial.println(_D1);
+  // Serial.println(_D2);
+
   //  TEST VALUES - comment lines above
-  // uint32_t D1 = 9085466;
-  // uint32_t D2 = 8569150;
+  // uint32_t _D1 = 9085466;
+  // uint32_t _D2 = 8569150;
 
   // TEMP & PRESS MATH - PAGE 7/20
   float dT = _D2 - C[5];
@@ -182,27 +192,30 @@ int MS5611::read(uint8_t bits)
   float offset =  C[2] + dT * C[4];
   float sens = C[1] + dT * C[3];
 
-  // SECOND ORDER COMPENSATION - PAGE 8/20
-  // COMMENT OUT < 2000 CORRECTION IF NOT NEEDED
-  // NOTE TEMPERATURE IS IN 0.01 C
-  if (_temperature < 2000)
+  if (_compensation)
   {
-    float T2 = dT * dT * 4.6566128731E-10;
-    float t = (_temperature - 2000) * (_temperature - 2000);
-    float offset2 = 2.5 * t;
-    float sens2 = 1.25 * t;
-    // COMMENT OUT < -1500 CORRECTION IF NOT NEEDED
-    if (_temperature < -1500)
+    // SECOND ORDER COMPENSATION - PAGE 8/20
+    // COMMENT OUT < 2000 CORRECTION IF NOT NEEDED
+    // NOTE TEMPERATURE IS IN 0.01 C
+    if (_temperature < 2000)
     {
-      t = (_temperature + 1500) * (_temperature + 1500);
-      offset2 += 7 * t;
-      sens2 += 5.5 * t;
+      float T2 = dT * dT * 4.6566128731E-10;
+      float t = (_temperature - 2000) * (_temperature - 2000);
+      float offset2 = 2.5 * t;
+      float sens2 = 1.25 * t;
+      // COMMENT OUT < -1500 CORRECTION IF NOT NEEDED
+      if (_temperature < -1500)
+      {
+        t = (_temperature + 1500) * (_temperature + 1500);
+        offset2 += 7 * t;
+        sens2 += 5.5 * t;
+      }
+      _temperature -= T2;
+      offset -= offset2;
+      sens -= sens2;
     }
-    _temperature -= T2;
-    offset -= offset2;
-    sens -= sens2;
+    // END SECOND ORDER COMPENSATION
   }
-  // END SECOND ORDER COMPENSATION
 
   _pressure = (_D1 * sens * 4.76837158205E-7 - offset) * 3.051757813E-5;
 

MS5611.h

@@ -3,7 +3,7 @@
 //    FILE: MS5611.h
 //  AUTHOR: Rob Tillaart
 //          Erni - testing/fixes
-// VERSION: 0.3.7
+// VERSION: 0.3.8
 // PURPOSE: Arduino library for MS5611 temperature and pressure sensor
 //     URL: https://github.com/RobTillaart/MS5611
 
@@ -30,7 +30,7 @@
 //  CS to GND  ==>  0x77
 
 
-#define MS5611_LIB_VERSION                    (F("0.3.7"))
+#define MS5611_LIB_VERSION                    (F("0.3.8"))
 
 #ifndef MS5611_DEFAULT_ADDRESS
 #define MS5611_DEFAULT_ADDRESS                0x77
@@ -63,7 +63,8 @@ class MS5611
   bool     isConnected();
 
   // reset command + get constants
-  void     reset();
+  // returns false if ROM constants == 0;
+  bool     reset();
 
   // the actual reading of the sensor;
   // returns MS5611_READ_OK upon success
@@ -97,6 +98,9 @@ class MS5611
 
   uint32_t getDeviceID() const     { return _deviceID; };
 
+  void     setCompensation(bool flag = true) { _compensation = flag; };
+  bool     getCompensation() { return _compensation; };
+
   // develop functions.
   /*
   void     setAddress(uint8_t address) { _address = address; };  // RANGE CHECK + isConnected() !
@@ -121,6 +125,7 @@ class MS5611
   float    C[7];
   uint32_t _lastRead;
   uint32_t _deviceID;
+  bool     _compensation;
 
   TwoWire * _wire;
 };

README.md

@@ -24,7 +24,7 @@ An experimental SPI version of the library can be found here
 - https://github.com/RobTillaart/MS5611_SPI
 
 
-#### breakout
+#### Breakout GY-63
 
 ```cpp
 //
@@ -48,7 +48,7 @@ An experimental SPI version of the library can be found here
 //
 ```
 
-#### related libraries
+#### Related libraries
 
 For pressure conversions see - https://github.com/RobTillaart/pressure
 
@@ -88,17 +88,28 @@ MS5611_DEFAULT_ADDRESS
 upon uniqueness of the factory calibration values.
 
 
+#### 0.3.8
+
+- reset() returns bool indicating succesful ROM read
+- get/setCompensation() to enable/disable compensation.
+
+
 ## Interface
 
 #### Base
 
 - **MS5611(uint8_t deviceAddress = MS5611_DEFAULT_ADDRESS)** constructor.
 Since 0.3.7 a default address 0x77 is added.
-- **bool begin(uint8_t sda, uint8_t scl, TwoWire \*wire = &Wire)** for ESP and alike, optionally set Wire interface. initializes internals, 
-- **bool begin(TwoWire \*wire = &Wire)** for UNO and alike, optionally set Wire interface. Initializes internals.
+- **bool begin(uint8_t sda, uint8_t scl, TwoWire \*wire = &Wire)** for ESP and alike, optionally set Wire interface. 
+Initializes internals by calling reset().
+Return false indicates either isConnected() error or reset() error.
+- **bool begin(TwoWire \*wire = &Wire)** for UNO and alike, optionally set Wire interface. 
+Initializes internals by calling reset().
+Return false indicates either isConnected() error or reset() error.
 - **bool isConnected()** checks availability of device address on the I2C bus.
 (see note above NANO 33 BLE).
-- **reset()** resets the chip and loads constants from its ROM.
+- **bool reset()** resets the chip and loads constants from its ROM.
+Returns false if ROM could not be read.
 - **int read(uint8_t bits)** the actual reading of the sensor. 
 Number of bits determines the oversampling factor. Returns MS5611_READ_OK upon success.
 - **int read()** wraps the **read()** above, uses the preset oversampling (see below). 
@@ -149,6 +160,10 @@ Default the offset is set to 0.
 
 - **int getLastResult()** checks last I2C communication. Replace with more informative error handling?
 - **uint32_t lastRead()** last time when **read()** was called in milliseconds since startup.
+
+
+#### DeviceID
+
 - **uint32_t getDeviceID()** returns the hashed values of the calibration PROM. 
 As these calibration are set in the factory and differ (enough) per sensor these can serve as an unique deviceID.
 
@@ -161,6 +176,14 @@ Having a device-ID can be used in many ways:
 Note: this is not an official ID from the device / datasheet, it is made up from calibration data.
 
 
+#### 2nd order pressure compensation
+
+- **setCompensation(bool flag = true)** to enable/desiable the 2nd order compensation. 
+The default = true. 
+Disabling the compensation will be slightly faster but you loose precision.
+- **getCompensation()** returns flag set above.
+
+
 ## Operation
 
 See examples
@@ -170,7 +193,7 @@ See examples
 
 - update documentation
   - separate release notes?
-- proper error handling
+- proper error handling.
 - redo lower level functions?
 - handle the read + math of temperature first? 
-- flag to enable / disable the compensation part?
+

library.json

@@ -18,7 +18,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/MS5611.git"
   },
-  "version": "0.3.7",
+  "version": "0.3.8",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*",

library.properties

@@ -1,5 +1,5 @@
 name=MS5611
-version=0.3.7
+version=0.3.8
 author=Rob Tillaart <[email protected]>
 maintainer=Rob Tillaart <[email protected]>
 sentence=Arduino library for MS5611 temperature and pressure sensor

test/unit_test_001.cpp

@@ -72,7 +72,7 @@ unittest(test_constants)
 unittest(test_constructor)
 {
   MS5611 sensor(0x77);
-  assertTrue(sensor.begin());
+  assertFalse(sensor.begin());  // as there is no sensor, and no ROM values.
 
   assertEqualFloat(-9.99, sensor.getTemperature(), 0.01);
   assertEqualFloat(-9.99, sensor.getPressure(),    0.01);
@@ -85,7 +85,7 @@ unittest(test_read_sensor)
 {
   MS5611 sensor(0x77);
 
-  assertTrue(sensor.begin());
+  assertFalse(sensor.begin());
 
   assureEqual(MS5611_READ_OK, sensor.read());
 
@@ -101,7 +101,7 @@ unittest(test_overSampling)
 {
   MS5611 sensor(0x77);
 
-  assertTrue(sensor.begin());
+  assertFalse(sensor.begin());
 
   // default
   assureEqual(OSR_ULTRA_LOW, sensor.getOversampling());