Fix #47, calibration register is 15 bit

CHANGELOG.md

@@ -6,6 +6,12 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.6.0] - 2024-05-27
+- Fix #47, calibration register is 15 bit, not 16 bit.
+- minor edits
+
+----
+
 ## [0.5.5] - 2024-04-22
 - Fix possible overflow in **getPower()**
 

INA226.cpp

@@ -1,6 +1,6 @@
 //    FILE: INA226.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.5.5
+// VERSION: 0.6.0
 //    DATE: 2021-05-18
 // PURPOSE: Arduino library for INA226 power sensor
 //     URL: https://github.com/RobTillaart/INA226
@@ -111,7 +111,7 @@ bool INA226::waitConversionReady(uint32_t timeout)
   while ( (millis() - start) <= timeout)
   {
     if (isConversionReady()) return true;
-   delay(1);  //  implicit yield();
+    delay(1);  //  implicit yield();
   }
   return false;
 }
@@ -214,14 +214,14 @@ int INA226::setMaxCurrentShunt(float maxCurrent, float shunt, bool normalize)
 
   _current_LSB = maxCurrent * 3.0517578125e-5;      //  maxCurrent / 32768;
 
-  #ifdef printdebug
-    Serial.println();
-    Serial.print("normalize:\t");
-    Serial.println(normalize ? " true":" false");
-    Serial.print("initial current_LSB:\t");
-    Serial.print(_current_LSB * 1e+6, 1);
-    Serial.println(" uA / bit");
-  #endif
+#ifdef printdebug
+  Serial.println();
+  Serial.print("normalize:\t");
+  Serial.println(normalize ? " true" : " false");
+  Serial.print("initial current_LSB:\t");
+  Serial.print(_current_LSB * 1e+6, 1);
+  Serial.println(" uA / bit");
+#endif
 
   //  normalize the LSB to a round number
   //  LSB will increase
@@ -232,25 +232,27 @@ int INA226::setMaxCurrentShunt(float maxCurrent, float shunt, bool normalize)
        (due to unusual low resistor values in relation to maxCurrent) determines currentLSB
        we have to take the upper value for currentLSB
 
+       (adjusted in 0.6.0)
        calculation of currentLSB based on shunt resistor and calibration register limits (2 bytes)
        cal = 0.00512 / ( shunt * currentLSB )
-       cal(max) = 2^16-1
+       cal(max) = 2^15-1
        currentLSB(min) = 0.00512 / ( shunt * cal(max) )
-       currentLSB(min) ~= 0.00512 / ( shunt * 2^16 )
-       currentLSB(min) ~= 2^9 * 1e-5 / ( shunt * 2^16 )
-       currentLSB(min) ~= 1e-5 / 2^7 / shunt
-       currentLSB(min) ~= 7.8125e-8 / shunt
+       currentLSB(min) ~= 0.00512 / ( shunt * 2^15 )
+       currentLSB(min) ~= 2^9 * 1e-5 / ( shunt * 2^15 )
+       currentLSB(min) ~= 1e-5 / 2^6 / shunt
+       currentLSB(min) ~= 1.5625e-7 / shunt
     */
-    if ( 7.8125e-8 / shunt > _current_LSB ) {
-      //  shunt resistor determines currentLSB -> take this a starting point for currentLSB
-      _current_LSB = 7.8125e-8 / shunt;
+    if ( 1.5625e-7 / shunt > _current_LSB ) {
+      //  shunt resistor determines current_LSB
+      //  => take this a starting point for current_LSB
+      _current_LSB = 1.5625e-7 / shunt;
     }
 
-    #ifdef printdebug
-      Serial.print("Pre-scale current_LSB:\t");
-      Serial.print(_current_LSB * 1e+6, 1);
-      Serial.println(" uA / bit");
-    #endif
+#ifdef printdebug
+    Serial.print("Pre-scale current_LSB:\t");
+    Serial.print(_current_LSB * 1e+6, 1);
+    Serial.println(" uA / bit");
+#endif
 
     //  normalize _current_LSB to a value of 1, 2 or 5 * 1e-6 to 1e-3
     //  convert float to int
@@ -274,24 +276,25 @@ int INA226::setMaxCurrentShunt(float maxCurrent, float shunt, bool normalize)
         factor *= 10;
         i++;
       }
-    } while( (i < 4) && (!result) );  //  factor < 10000
+    } while ( (i < 4) && (!result) );  //  factor < 10000
 
-    if (result == false) {  //  not succeeded to normalize.
+    if (result == false)  //  not succeeded to normalize.
+    {
       _current_LSB = 0;
       return INA226_ERR_NORMALIZE_FAILED;
     }
 
-    #ifdef printdebug
-      Serial.print("After scale current_LSB:\t");
-      Serial.print(_current_LSB * 1e+6, 1);
-      Serial.println(" uA / bit");
-    #endif
+#ifdef printdebug
+    Serial.print("After scale current_LSB:\t");
+    Serial.print(_current_LSB * 1e+6, 1);
+    Serial.println(" uA / bit");
+#endif
     // done
   }
 
   //  auto scale calibration if needed.
   uint32_t calib = round(0.00512 / (_current_LSB * shunt));
-  while (calib > 65535)
+  while (calib > 32767)
   {
     _current_LSB *= 2;
     calib >>= 1;
@@ -301,22 +304,22 @@ int INA226::setMaxCurrentShunt(float maxCurrent, float shunt, bool normalize)
   _maxCurrent = _current_LSB * 32768;
   _shunt = shunt;
 
-  #ifdef printdebug
-    Serial.print("Final current_LSB:\t");
-    Serial.print(_current_LSB * 1e+6, 1);
-    Serial.println(" uA / bit");
-    Serial.print("Calibration:\t");
-    Serial.println(calib);
-    Serial.print("Max current:\t");
-    Serial.print(_maxCurrent, 3);
-    Serial.println(" A");
-    Serial.print("Shunt:\t");
-    Serial.print(_shunt, 4);
-    Serial.println(" Ohm");
-    Serial.print("ShuntV:\t");
-    Serial.print(shuntVoltage, 4);
-    Serial.println(" Volt");
-  #endif
+#ifdef printdebug
+  Serial.print("Final current_LSB:\t");
+  Serial.print(_current_LSB * 1e+6, 1);
+  Serial.println(" uA / bit");
+  Serial.print("Calibration:\t");
+  Serial.println(calib);
+  Serial.print("Max current:\t");
+  Serial.print(_maxCurrent, 3);
+  Serial.println(" A");
+  Serial.print("Shunt:\t");
+  Serial.print(_shunt, 4);
+  Serial.println(" Ohm");
+  Serial.print("ShuntV:\t");
+  Serial.print(shuntVoltage, 4);
+  Serial.println(" Volt");
+#endif
 
   return INA226_ERR_NONE;
 }

INA226.h

@@ -1,7 +1,7 @@
 #pragma once
 //    FILE: INA226.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.5.5
+// VERSION: 0.6.0
 //    DATE: 2021-05-18
 // PURPOSE: Arduino library for INA226 power sensor
 //     URL: https://github.com/RobTillaart/INA226
@@ -13,7 +13,7 @@
 #include "Wire.h"
 
 
-#define INA226_LIB_VERSION              "0.5.5"
+#define INA226_LIB_VERSION              "0.6.0"
 
 
 //  set by setAlertRegister

README.md

@@ -55,6 +55,7 @@ before calling **begin()**.
 - https://www.ti.com/document-viewer/INA226/datasheet
 - https://github.com/RobTillaart/INA219
 - https://github.com/RobTillaart/INA226
+- https://github.com/RobTillaart/INA236
 
 
 ## I2C
@@ -65,26 +66,26 @@ The sensor can have 16 different I2C addresses,
 which depends on how the A0 and A1 address lines 
 are connected to the SCL, SDA, GND and VCC pins.
 
-See table - from datasheet table 2, page18.
-
-|  A1   |  A0   |  ADDRESS   |
-|:-----:|:-----:|:----------:|
-|  GND  |  GND  |  1000000   |
-|  GND  |  VS   |  1000001   |
-|  GND  |  SDA  |  1000010   |
-|  GND  |  SCL  |  1000011   |
-|  VS   |  GND  |  1000100   |
-|  VS   |  VS   |  1000101   |
-|  VS   |  SDA  |  1000110   |
-|  VS   |  SCL  |  1000111   |
-|  SDA  |  GND  |  1001000   |
-|  SDA  |  VS   |  1001001   |
-|  SDA  |  SDA  |  1001010   |
-|  SDA  |  SCL  |  1001011   |
-|  SCL  |  GND  |  1001100   |
-|  SCL  |  VS   |  1001101   |
-|  SCL  |  SDA  |  1001110   |
-|  SCL  |  SCL  |  1001111   |
+See table - from datasheet table 2, page 18.
+
+|  A1   |  A0   |  Addr  |  HEX   |
+|:-----:|:-----:|:------:|:------:|
+|  GND  |  GND  |   64   |  0x40  |
+|  GND  |  VS   |   65   |  0x41  |
+|  GND  |  SDA  |   66   |  0x42  |
+|  GND  |  SCL  |   67   |  0x43  |
+|  VS   |  GND  |   68   |  0x44  |
+|  VS   |  VS   |   69   |  0x45  |
+|  VS   |  SDA  |   70   |  0x46  |
+|  VS   |  SCL  |   71   |  0x47  |
+|  SDA  |  GND  |   72   |  0x48  |
+|  SDA  |  VS   |   73   |  0x49  |
+|  SDA  |  SDA  |   74   |  0x4A  |
+|  SDA  |  SCL  |   75   |  0x4B  |
+|  SCL  |  GND  |   76   |  0x4C  |
+|  SCL  |  VS   |   77   |  0x4D  |
+|  SCL  |  SDA  |   78   |  0x4E  |
+|  SCL  |  SCL  |   79   |  0x4F  |
 
 
 #### Performance
@@ -230,7 +231,7 @@ Note the value returned is not a unit of time.
 
 
 |  enum description  | BVCT SVCT |   time    |  notes  |
-|:------------------:|:---------:|----------:|--------:|
+|:------------------:|:---------:|:---------:|--------:|
 |  INA226_140_us     |     0     |  140 us   |
 |  INA226_204_us     |     1     |  204 us   |
 |  INA226_332_us     |     2     |  332 us   |
@@ -285,7 +286,7 @@ See https://github.com/RobTillaart/INA226/pull/29 for details of the discussion.
 #### Error codes setMaxCurrentShunt
 
 |  descriptive name error        |  value   |  meaning  |
-|:-------------------------------|---------:|:----------|
+|:-------------------------------|:--------:|:----------|
 |  INA226_ERR_NONE               |  0x0000  |  OK
 |  INA226_ERR_SHUNTVOLTAGE_HIGH  |  0x8000  |  maxCurrent \* shunt > 80 mV 
 |  INA226_ERR_MAXCURRENT_LOW     |  0x8001  |  maxCurrent < 0.001
@@ -329,7 +330,7 @@ Returns true if write to register successful.
 
 
 |  description alert register  |  value   | a.k.a.  |
-|:-----------------------------|---------:| -------:|
+|:-----------------------------|:--------:| -------:|
 |  INA226_SHUNT_OVER_VOLTAGE   |  0x8000  |  SOL    |
 |  INA226_SHUNT_UNDER_VOLTAGE  |  0x4000  |  SUL    |
 |  INA226_BUS_OVER_VOLTAGE     |  0x2000  |  BOL    |
@@ -339,7 +340,7 @@ Returns true if write to register successful.
 
 
 |  description alert flags         |  value   |
-|:---------------------------------|---------:|
+|:---------------------------------|:--------:|
 |  INA226_ALERT_FUNCTION_FLAG      |  0x0010  |
 |  INA226_CONVERSION_READY_FLAG    |  0x0008  |
 |  INA226_MATH_OVERFLOW_FLAG       |  0x0004  |
@@ -381,11 +382,6 @@ Be aware that
 - you do this at your own risk.
 
 
-## Operational
-
-See examples.. 
-
-
 ## Future
 
 

examples/INA226_setMaxCurrentShunt/INA226_setMaxCurrentShunt.ino

@@ -33,12 +33,14 @@ void setup()
   delay(100);
 
 
-  INA.setMaxCurrentShunt(1, 0.002);
+  int x = INA.setMaxCurrentShunt(1, 0.002);
   Serial.println("normalized = true (default)");
+  Serial.println(x);
   printConfig();
 
-  INA.setMaxCurrentShunt(1, 0.002, false);
+  x = INA.setMaxCurrentShunt(1, 0.002, false);
   Serial.println("normalized = false");
+  Serial.println(x);
   printConfig();
 
 
@@ -54,10 +56,10 @@ void setup()
 
 void loop()
 {
-  INA.setMaxCurrentShunt(1, 0.002);
+  INA.setMaxCurrentShunt(1, 0.100);
   measure(20);
 
-  INA.setMaxCurrentShunt(1, 0.002, false);
+  INA.setMaxCurrentShunt(1, 0.100, false);
   measure(20);
 }
 

library.json

@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/INA226.git"
   },
-  "version": "0.5.5",
+  "version": "0.6.0",
   "license": "MIT",
   "frameworks": "*",
   "platforms": "*",

library.properties

@@ -1,5 +1,5 @@
 name=INA226
-version=0.5.5
+version=0.6.0
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=Arduino library for INA226 power sensor