Fix getShuntVoltage() + add getMaxShuntVoltage() (#21)

- fix **float getShuntVoltage()** for negative values, kudos to aguilerabr
- add **int getMaxShuntVoltage()**, depends on GAIN (Table 7).
- removed default for **setGain()** as it was not sensors default.
- update readme.md

CHANGELOG.md

@@ -6,6 +6,14 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.4.0] - 2024-08-14
+- fix **float getShuntVoltage()** for negative values, kudos to aguilerabr
+- add **int getMaxShuntVoltage()**, depends on GAIN (Table 7).
+- removed default for **setGain()** as it was not sensors default.
+- update readme.md
+
+----
+
 ## [0.3.1] - 2024-04-22
 - Bump version after Fix #17, Kudos to ChrisRed255
 

INA219.cpp

@@ -1,6 +1,6 @@
 //    FILE: INA219.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.3.1
+// VERSION: 0.4.0
 //    DATE: 2021-05-18
 // PURPOSE: Arduino library for INA219 voltage, current and power sensor
 //     URL: https://github.com/RobTillaart/INA219
@@ -167,6 +167,7 @@ bool INA219::setGain(uint8_t factor)
   }
   uint16_t config = _readRegister(INA219_CONFIGURATION);
   config &= ~INA219_CONF_PROG_GAIN;
+  //  factor == 1 ==> mask = 00
   if      (factor == 2) config |= (1 << 11);
   else if (factor == 4) config |= (2 << 11);
   else if (factor == 8) config |= (3 << 11);
@@ -187,6 +188,13 @@ uint8_t INA219::getGain()
 }
 
 
+int INA219::getMaxShuntVoltage()
+{
+  int gain = getGain();  //  1,  2,  4,   8
+  return gain * 40;      //  40, 80, 160, 320
+}
+
+
 ////////////////////////////////////////////////////////
 //
 //  BUS

INA219.h

@@ -1,7 +1,7 @@
 #pragma once
 //    FILE: INA219.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.3.1
+// VERSION: 0.4.0
 //    DATE: 2021-05-18
 // PURPOSE: Arduino library for INA219 voltage, current and power sensor
 //     URL: https://github.com/RobTillaart/INA219
@@ -13,7 +13,7 @@
 #include "Wire.h"
 
 
-#define INA219_LIB_VERSION              (F("0.3.1"))
+#define INA219_LIB_VERSION              (F("0.4.0"))
 
 
 class INA219
@@ -54,9 +54,14 @@ class INA219
   //  voltage = 16, 32  (values below 32 are rounded to 16 or 32)
   bool     setBusVoltageRange(uint8_t voltage = 16);
   uint8_t  getBusVoltageRange();  //  returns 16 or 32.
-  //  factor = 1, 2, 4, 8
-  bool     setGain(uint8_t factor = 1);
+  //  factor = 1, 2, 4, 8 (8 = sensor default)
+  bool     setGain(uint8_t factor);  //  removed default parameter.
   uint8_t  getGain();
+  //  MaxShuntVoltagedepends on GAIN, 
+  //  See Table 7. Shunt Voltage Register Format
+  //  default = 320.
+  int      getMaxShuntVoltage();
+
 
   //  configuration BUS
   //  use one of the next three

README.md

@@ -33,6 +33,12 @@ A few important maxima, see datasheet, chapter 7, esp 7.5
 
 
 
+#### 0.4.0 Breaking change
+
+Version 0.4.0 fixed negative values for **getShuntVoltage()**.
+Older versions are obsolete now.
+
+
 #### 0.2.0 Breaking change
 
 Version 0.2.0 introduced a breaking change.
@@ -146,14 +152,16 @@ See section below.
 Returns false if it could not write settings to device.
 - **bool setBusVoltageRange(uint8_t voltage = 16)** set to 16 or 32.
 Values <= 16 map to 16 and values between 16 and 32 map to 32.
-Returns false if voltage is above 32..
+Returns false if voltage is above 32.
 Returns false if it could not write settings to device.
 - **uint8_t getBusVoltageRange()** returns 16 or 32. (Volts)
-- **bool setGain(uint8_t factor = 1)** factor = 1, 2, 4, 8.
+- **bool setGain(uint8_t factor)** factor = 1, 2, 4, 8 (default).
 Determines the shunt voltage range. 40, 80, 160 or 320 mV. 
 Returns false if factor is not a valid value.
 Returns false if it could not write settings to device.
 - **uint8_t getGain()** returns set factor.
+- **int getMaxShuntVoltage()** returns 40, 80, 160 or 320 (mV).
+320 is the sensors default.
 
 
 #### Configuration BUS and SHUNT

keywords.txt

@@ -32,6 +32,7 @@ setBusVoltageRange	KEYWORD2
 getBusVoltageRange	KEYWORD2
 setGain	KEYWORD2
 getGain	KEYWORD2
+getMaxShuntVoltage	KEYWORD2
 
 setBusResolution	KEYWORD2
 setBusSamples	KEYWORD2

library.json

@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/INA219.git"
   },
-  "version": "0.3.1",
+  "version": "0.4.0",
   "license": "MIT",
   "frameworks": "*",
   "platforms": "*",

library.properties

@@ -1,5 +1,5 @@
 name=INA219
-version=0.3.1
+version=0.4.0
 author=Rob Tillaart <[email protected]>
 maintainer=Rob Tillaart <[email protected]>
 sentence=Arduino library for INA219 voltage, current and power sensor.