fix #68, gain for ADS1x13 (#69)

- fix #68, gain bugs ADS1x13
- add unit test for ADS1x13
- update GitHub/actions to v4
- removed depreciated **getLastValue()**
- add multiplexer section to readme.md

.github/workflows/arduino-lint.yml

@@ -6,7 +6,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: arduino/arduino-lint-action@v1
         with:
           library-manager: update

.github/workflows/arduino_test_runner.yml

@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: 2.6

.github/workflows/jsoncheck.yml

@@ -10,7 +10,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@v4
       - name: json-syntax-check
         uses: limitusus/json-syntax-check@v1
         with:

ADS1X15.cpp

@@ -1,7 +1,7 @@
 //
 //    FILE: ADS1X15.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.4.1
+// VERSION: 0.4.2
 //    DATE: 2013-03-24
 // PURPOSE: Arduino library for ADS1015 and ADS1115
 //     URL: https://github.com/RobTillaart/ADS1X15
@@ -193,7 +193,7 @@ float ADS1X15::toVoltage(int16_t value)
   if (value == 0) return 0;
 
   float volts = getMaxVoltage();
-  if (volts < 0) return volts;
+  if (volts < 0) return volts;    //  propagate error
 
   volts *= value;
   if (_config & ADS_CONF_RES_16)
@@ -530,6 +530,22 @@ ADS1013::ADS1013(uint8_t address, TwoWire *wire)
   _conversionDelay = ADS1015_CONVERSION_DELAY;
   _bitShift = 4;
   _maxPorts = 1;
+  _gain     = ADS1X15_PGA_2_048V;  //  fixed value
+}
+
+
+//  ADS1x13 has no gain so set default.
+//  Table 8. Config Register Field Descriptions
+void ADS1013::setGain(uint8_t gain)
+{
+  _gain = gain;  //  keep compiler happy.
+  _gain = ADS1X15_PGA_2_048V;  //  fixed value
+}
+
+
+uint8_t ADS1013::getGain()
+{
+  return 2;  //  fixed value
 }
 
 
@@ -623,6 +639,22 @@ ADS1113::ADS1113(uint8_t address, TwoWire *wire)
   _conversionDelay = ADS1115_CONVERSION_DELAY;
   _bitShift = 0;
   _maxPorts = 1;
+  _gain     = ADS1X15_PGA_2_048V;  //  fixed value
+}
+
+
+//  ADS1x13 has no gain so set default.
+//  Table 8. Config Register Field Descriptions
+void ADS1113::setGain(uint8_t gain)
+{
+  _gain = gain;  //  keep compiler happy.
+  _gain = ADS1X15_PGA_2_048V;  //  fixed value
+}
+
+
+uint8_t ADS1113::getGain()
+{
+  return 2;  //  fixed value
 }
 
 

ADS1X15.h

@@ -2,7 +2,7 @@
 //
 //    FILE: ADS1X15.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.4.1
+// VERSION: 0.4.2
 //    DATE: 2013-03-24
 // PURPOSE: Arduino library for ADS1015 and ADS1115
 //     URL: https://github.com/RobTillaart/ADS1X15
@@ -12,7 +12,7 @@
 #include "Arduino.h"
 #include "Wire.h"
 
-#define ADS1X15_LIB_VERSION               (F("0.4.1"))
+#define ADS1X15_LIB_VERSION               (F("0.4.2"))
 
 //  allow compile time default address
 //  address in { 0x48, 0x49, 0x4A, 0x4B }, no test...
@@ -72,8 +72,8 @@ class ADS1X15
   int16_t  readADC_Differential_0_1();
 
   //  used by continuous mode and async mode.
-  [[deprecated("Use getValue() instead")]]
-  int16_t  getLastValue() { return getValue(); };  //  will be obsolete in the future 0.4.0
+  //  [[deprecated("Use getValue() instead")]]
+  //  int16_t  getLastValue() { return getValue(); };  //  will be obsolete in the future 0.4.0
   int16_t  getValue();
 
 
@@ -86,7 +86,7 @@ class ADS1X15
   bool     isReady();
 
 
-  //  returns a pin 0x0[0..3] or 
+  //  returns a pin 0x0[0..3] or
   //          a differential "mode" 0x[pin second][pin first] or
   //          0xFF (no request / invalid request)
   uint8_t   lastRequest();
@@ -164,7 +164,7 @@ class ADS1X15
   uint8_t  _compLatch;
   uint8_t  _compQueConvert;
 
-  //  variable to track the last pin requested, 
+  //  variable to track the last pin requested,
   //  to allow for round robin query of
   //  pins based on this state == if no last request then == 0xFFFF.
   uint16_t  _lastRequest;
@@ -188,6 +188,8 @@ class ADS1013 : public ADS1X15
 {
 public:
   ADS1013(uint8_t Address = ADS1015_ADDRESS, TwoWire *wire = &Wire);
+  void setGain(uint8_t gain);
+  uint8_t getGain();
 };
 
 
@@ -217,6 +219,8 @@ class ADS1113 : public ADS1X15
 {
 public:
   ADS1113(uint8_t address = ADS1115_ADDRESS, TwoWire *wire = &Wire);
+  void setGain(uint8_t gain);
+  uint8_t getGain();
 };
 
 

CHANGELOG.md

@@ -5,11 +5,18 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.4.2] - 2024-03-04
+- fix #68, gain bugs ADS1x13
+- add unit test for ADS1x13
+- update GitHub/actions to v4
+- removed depreciated **getLastValue()**
+- add multiplexer section to readme.md
+
+
 ## [0.4.1] - 2024-01-02
 - fix some typos
 - minor edits
 
-
 ## [0.4.0] - 2023-12-06
 - refactor API, begin()
 - update readme.md

README.md

@@ -65,6 +65,24 @@ is connected to:
 |        SCL              |   0x4B    |           |
 
 
+#### I2C multiplexing
+
+Sometimes you need to control more devices than possible with the default
+address range the device provides.
+This is possible with an I2C multiplexer e.g. TCA9548 which creates up 
+to eight channels (think of it as I2C subnets) which can use the complete 
+address range of the device. 
+
+Drawback of using a multiplexer is that it takes more administration in 
+your code e.g. which device is on which channel. 
+This will slow down the access, which must be taken into account when
+deciding which devices are on which channel.
+Also note that switching between channels will slow down other devices 
+too if they are behind the multiplexer.
+
+- https://github.com/RobTillaart/TCA9548
+
+
 ## Interface
 
 ```cpp

examples/ADS1113_getMaxVoltage/ADS1113_getMaxVoltage.ino

@@ -0,0 +1,49 @@
+//
+//    FILE: ADS1113_getMaxVoltage.ino
+//  AUTHOR: Rob.Tillaart
+// PURPOSE: read analog inputs - straightforward.
+//     URL: https://github.com/RobTillaart/ADS1X15
+
+//  test for issue #68 behaviour ADS1113 / ADS1013
+//
+//  connect 1 potmeter per port.
+//
+//  GND ---[   x   ]------ 5V
+//             |
+//
+//  measure at x (connect to AIN0).
+
+
+#include "ADS1X15.h"
+
+ADS1113 ADS(0x48);
+
+
+void setup() 
+{
+  Serial.begin(115200);
+  Serial.println(__FILE__);
+  Serial.print("ADS1X15_LIB_VERSION: ");
+  Serial.println(ADS1X15_LIB_VERSION);
+
+  Wire.begin();
+  ADS.begin();
+
+  for (int g = 0; g < 8; g++)
+  {
+    ADS.setGain(g);
+    Serial.print(g);
+    Serial.print('\t');
+    Serial.print(ADS.getGain());             //  should all print 2
+    Serial.print('\t');
+    Serial.println(ADS.getMaxVoltage(), 3);  //  should all print 2.048
+  }
+}
+
+
+void loop() 
+{
+}
+
+
+//  -- END OF FILE --

keywords.txt

@@ -1,7 +1,8 @@
 # Syntax Colouring Map For ADS1X15
 
 # Data types (KEYWORD1)
-ADS1X13	KEYWORD1
+ADS1X15	KEYWORD1
+ADS1013	KEYWORD1
 ADS1014	KEYWORD1
 ADS1015	KEYWORD1
 ADS1015	KEYWORD1

library.json

@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/ADS1X15"
   },
-  "version": "0.4.1",
+  "version": "0.4.2",
   "license": "MIT",
   "frameworks": "*",
   "platforms": "*",

library.properties

@@ -1,5 +1,5 @@
 name=ADS1X15
-version=0.4.1
+version=0.4.2
 author=Rob Tillaart <[email protected]>
 maintainer=Rob Tillaart <[email protected]>
 sentence=Arduino library for ADS1015 - I2C 12 bit ADC and ADS1115 I2C 16 bit ADC

test/unit_test_001.cpp

@@ -79,6 +79,30 @@ unittest(test_gain)
 }
 
 
+//  For issue #68, #2
+unittest(test_gain_ADS1113)
+{
+  ADS1113 ADS(0x48);
+
+  Wire.begin();
+
+  assertTrue(ADS.begin());
+
+  assertEqual(2, ADS.getGain());
+  int gains[6] = { 0,1,2,4,8,16 };
+  for (int i = 0; i < 6; i++)
+  {
+    ADS.setGain(gains[i]);
+    assertEqual(2, ADS.getGain());
+    assertEqualFloat(2.048, ADS.getMaxVoltage(), 0.001);
+  }
+
+  ADS.setGain(42);
+  assertEqual(2, ADS.getGain());
+  assertEqualFloat(2.048, ADS.getMaxVoltage(), 0.001);
+}
+
+
 unittest(test_Voltage)
 {
   ADS1115 ADS(0x48);
@@ -93,6 +117,26 @@ unittest(test_Voltage)
   float delta = abs(6.144 - volts);
   assertMoreOrEqual(0.001, delta);
 
+  ADS.setGain(1);
+  volts = ADS.getMaxVoltage();
+  delta = abs(4.096 - volts);
+  assertMoreOrEqual(0.001, delta);
+
+  ADS.setGain(2);
+  volts = ADS.getMaxVoltage();
+  delta = abs(2.048 - volts);
+  assertMoreOrEqual(0.001, delta);
+
+  ADS.setGain(4);
+  volts = ADS.getMaxVoltage();
+  delta = abs(1.024 - volts);
+  assertMoreOrEqual(0.001, delta);
+
+  ADS.setGain(8);
+  volts = ADS.getMaxVoltage();
+  delta = abs(0.512 - volts);
+  assertMoreOrEqual(0.001, delta);
+
   ADS.setGain(16);
   volts = ADS.getMaxVoltage();
   delta = abs(0.256 - volts);