Changed value to float

Adafruit_INA219.cpp

@@ -38,7 +38,7 @@ void Adafruit_INA219::wireWriteRegister (uint8_t reg, uint16_t value)
   Wire.beginTransmission(INA219_ADDRESS);
   #if ARDUINO >= 100
     Wire.write(reg);                       // Register
-    Wire.write(value >> 8);                // Upper 8-bits
+    Wire.write((value >> 8) & 0xFF);       // Upper 8-bits
     Wire.write(value & 0xFF);              // Lower 8-bits
   #else
     Wire.send(reg);                        // Register
@@ -55,6 +55,7 @@ void Adafruit_INA219::wireWriteRegister (uint8_t reg, uint16_t value)
 /**************************************************************************/
 void Adafruit_INA219::wireReadRegister(uint8_t reg, uint16_t *value)
 {
+
   Wire.beginTransmission(INA219_ADDRESS);
   #if ARDUINO >= 100
     Wire.write(reg);                       // Register
@@ -66,10 +67,10 @@ void Adafruit_INA219::wireReadRegister(uint8_t reg, uint16_t *value)
   Wire.requestFrom(INA219_ADDRESS, 2);  
   #if ARDUINO >= 100
     // Shift values to create properly formed integer
-    *value = ((Wire.read() << 8) | Wire.read());
+    *value = ((Wire.read() << 8) + Wire.read());
   #else
     // Shift values to create properly formed integer
-    *value = ((Wire.receive() << 8) | Wire.receive());
+    *value = ((Wire.receive() << 8) + Wire.receive());
   #endif
 }
 
@@ -273,50 +274,71 @@ void Adafruit_INA219::begin() {
   // Set chip to known config values to start
   ina219SetCalibration_32V_2A();
 }
- 
+
 /**************************************************************************/
 /*! 
-    @brief  Gets the shunt voltage (16-bit signed integer, so +-32767)
+    @brief  Gets the raw bus voltage (16-bit signed integer, so +-32767)
 */
 /**************************************************************************/
-int16_t Adafruit_INA219::getShuntVoltage() {
+uint16_t Adafruit_INA219::getBusVoltage_raw() {
   uint16_t value;
-  wireReadRegister(INA219_REG_SHUNTVOLTAGE, &value);
-  return value;
+  wireReadRegister(INA219_REG_BUSVOLTAGE, &value);
+
+  // Shift to the right 3 to drop CNVR and OVF and multiply by LSB
+  return (value >> 3) * 4;
 }
 
 /**************************************************************************/
 /*! 
-    @brief  Gets the shunt voltage (16-bit signed integer, so +-32767)
+    @brief  Gets the raw shunt voltage (16-bit signed integer, so +-32767)
 */
 /**************************************************************************/
-int16_t Adafruit_INA219::getBusVoltage() {
+uint16_t Adafruit_INA219::getShuntVoltage_raw() {
   uint16_t value;
-  wireReadRegister(INA219_REG_BUSVOLTAGE, &value);
-  // Shift to the right 3 to drop CNVR and OVF and then multiply by LSB
-  return (value >> 3) * 4;
+  wireReadRegister(INA219_REG_SHUNTVOLTAGE, &value);
+  return value;
 }
 
 /**************************************************************************/
 /*! 
     @brief  Gets the raw current value (16-bit signed integer, so +-32767)
 */
 /**************************************************************************/
-int16_t Adafruit_INA219::getCurrent() {
+uint16_t Adafruit_INA219::getCurrent_raw() {
   uint16_t value;
   wireReadRegister(INA219_REG_CURRENT, &value);
   return value;
 }
+
+/**************************************************************************/
+/*! 
+    @brief  Gets the shunt voltage in mV (so +-327mV)
+*/
+/**************************************************************************/
+float Adafruit_INA219::getShuntVoltage_mV() {
+  uint16_t value;
+  value = getShuntVoltage_raw();
+  return value * 0.01;
+}
+
+/**************************************************************************/
+/*! 
+    @brief  Gets the shunt voltage in volts
+*/
+/**************************************************************************/
+float Adafruit_INA219::getBusVoltage_V() {
+  uint16_t value = getBusVoltage_raw();
+  return value * 0.001;
+}
 
 /**************************************************************************/
 /*! 
     @brief  Gets the current value in mA, taking into account the
             config settings and current LSB
 */
 /**************************************************************************/
-int16_t Adafruit_INA219::getCurrent_mA() {
-  uint16_t value;
-  wireReadRegister(INA219_REG_CURRENT, &value);
-  return value / ina219_currentDivider_mA;
+float Adafruit_INA219::getCurrent_mA() {
+  float valueDec = getCurrent_raw() / ina219_currentDivider_mA;
+  return valueDec;
 }
 

Adafruit_INA219.h

@@ -113,10 +113,9 @@ class Adafruit_INA219{
  public:
   Adafruit_INA219();
   void begin(void);
-  int16_t getShuntVoltage(void);
-  int16_t getBusVoltage(void);
-  int16_t getCurrent(void);
-  int16_t getCurrent_mA(void);
+  float getBusVoltage_V(void);
+  float getShuntVoltage_mV(void);
+  float getCurrent_mA(void);
 
  private:
   // The following multipliers are used to convert raw current and power
@@ -128,4 +127,7 @@ class Adafruit_INA219{
   void wireReadRegister(uint8_t reg, uint16_t *value);
   void ina219SetCalibration_32V_2A(void);
   void ina219SetCalibration_32V_1A(void);
+  uint16_t getBusVoltage_raw(void);
+  uint16_t getShuntVoltage_raw(void);
+  uint16_t getCurrent_raw(void);
 };

examples/getcurrent/getcurrent.pde

@@ -10,26 +10,26 @@ void setup(void)
   Serial.begin(115200);
   Serial.println("Hello!");
 
-  Serial.print("Measuring voltage and current with INA219 ...");
+  Serial.println("Measuring voltage and current with INA219 ...");
   ina219.begin();
 }
 
 void loop(void) 
 {
-  int16_t current_mA = 0;
-  int16_t busvoltage = 0;
-  int16_t shuntvoltage = 0;
-  int16_t loadvoltage = 0;
-  
-  shuntvoltage = ina219.getShuntVoltage();
-  busvoltage = ina219.getBusVoltage();
+  float shuntvoltage = 0;
+  float busvoltage = 0;
+  float current_mA = 0;
+  float loadvoltage = 0;
+
+  shuntvoltage = ina219.getShuntVoltage_mV();
+  busvoltage = ina219.getBusVoltage_V();
   current_mA = ina219.getCurrent_mA();
-  loadvoltage = busvoltage + (shuntvoltage / 100);
+  loadvoltage = busvoltage + (shuntvoltage / 1000);
 
-  Serial.print("Shunt Voltage: "); Serial.print(shuntvoltage/100); Serial.print('.'); Serial.print(shuntvoltage%100); Serial.println("V");
-  Serial.print("Bus Voltage:   "); Serial.print(busvoltage/1000); Serial.print('.'); Serial.print(busvoltage%1000); Serial.println("V");
-  Serial.print("Load Voltage:  "); Serial.print(loadvoltage/1000); Serial.print('.'); Serial.print(loadvoltage%1000); Serial.println("V");
-  Serial.print("Current:       "); Serial.print(current_mA); Serial.println("mA");
+  Serial.print("Bus Voltage:   "); Serial.print(busvoltage); Serial.println(" V");
+  Serial.print("Shunt Voltage: "); Serial.print(shuntvoltage); Serial.println(" mV");
+  Serial.print("Load Voltage:  "); Serial.print(loadvoltage); Serial.println(" V");
+  Serial.print("Current:       "); Serial.print(current_mA); Serial.println(" mA");
   Serial.println("");
 
   delay(2000);