diff --git a/LICENSE b/LICENSE
index 8eba944..c3d6b3d 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2020-2021 Rob Tillaart
+Copyright (c) 2020-2022 Rob Tillaart
 
 Permission is hereby granted, free of charge, to any person obtaining a copy
 of this software and associated documentation files (the "Software"), to deal
diff --git a/PCF8575.cpp b/PCF8575.cpp
index d3187b9..cf709eb 100644
--- a/PCF8575.cpp
+++ b/PCF8575.cpp
@@ -2,7 +2,7 @@
 //    FILE: PCF8575.cpp
 //  AUTHOR: Rob Tillaart
 //    DATE: 2020-07-20
-// VERSION: 0.1.3
+// VERSION: 0.1.4
 // PURPOSE: Arduino library for PCF8575 - 16 channel I2C IO expander
 //     URL: https://github.com/RobTillaart/PCF8575
 //
@@ -15,6 +15,7 @@
 //  0.1.2   2021-07-09  fix #10 add set/getAddress() function 
 //  0.1.3   2021-12-01  update build-CI, readme
 //                      add getButtonMask()
+//  0.1.4   2021-12-23  update library.json, license, minor edits
 
 
 #include "PCF8575.h"
@@ -32,7 +33,7 @@ PCF8575::PCF8575(const uint8_t deviceAddress, TwoWire *wire)
 
 
 #if defined (ESP8266) || defined(ESP32)
-bool PCF8575::begin(uint8_t dataPin, uint8_t clockPin, uint16_t val)
+bool PCF8575::begin(uint8_t dataPin, uint8_t clockPin, uint16_t value)
 {
   _wire      = &Wire;
   if ((dataPin < 255) && (clockPin < 255))
@@ -42,17 +43,17 @@ bool PCF8575::begin(uint8_t dataPin, uint8_t clockPin, uint16_t val)
     _wire->begin();
   }
   if (! isConnected()) return false;
-  PCF8575::write16(val);
+  PCF8575::write16(value);
   return true;
 }
 #endif
 
 
-bool PCF8575::begin(uint16_t val)
+bool PCF8575::begin(uint16_t value)
 {
   _wire->begin();
   if (! isConnected()) return false;
-  PCF8575::write16(val);
+  PCF8575::write16(value);
   return true;
 }
 
@@ -152,7 +153,7 @@ void PCF8575::toggleMask(const uint16_t mask)
 void PCF8575::shiftRight(const uint8_t n)
 {
   if ((n == 0) || (_dataOut == 0)) return;
-  if (n > 15)         _dataOut = 0;    // shift 8++ clears all, valid...
+  if (n > 15)         _dataOut = 0;    // shift 15++ clears all, valid...
   if (_dataOut != 0) _dataOut >>= n;   // only shift if there are bits set
   PCF8575::write16(_dataOut);
 }
@@ -161,7 +162,7 @@ void PCF8575::shiftRight(const uint8_t n)
 void PCF8575::shiftLeft(const uint8_t n)
 {
   if ((n == 0) || (_dataOut == 0)) return;
-  if (n > 15)        _dataOut = 0;    // shift 8++ clears all, valid...
+  if (n > 15)        _dataOut = 0;    // shift 15++ clears all, valid...
   if (_dataOut != 0) _dataOut <<= n;  // only shift if there are bits set
   PCF8575::write16(_dataOut);
 }
@@ -229,3 +230,4 @@ uint8_t PCF8575::readButton(const uint8_t pin)
 
 
 // -- END OF FILE --
+
diff --git a/PCF8575.h b/PCF8575.h
index 8256a8e..684cda3 100644
--- a/PCF8575.h
+++ b/PCF8575.h
@@ -3,7 +3,7 @@
 //    FILE: PCF8575.h
 //  AUTHOR: Rob Tillaart
 //    DATE: 2020-07-20
-// VERSION: 0.1.3
+// VERSION: 0.1.4
 // PURPOSE: Arduino library for PCF8575 - 16 channel I2C IO expander
 //     URL: https://github.com/RobTillaart/PCF8575
 //
@@ -16,7 +16,7 @@
 #include "Wire.h"
 
 
-#define PCF8575_LIB_VERSION      (F("0.1.3"))
+#define PCF8575_LIB_VERSION      (F("0.1.4"))
 
 
 #ifndef PCF8575_INITIAL_VALUE
@@ -32,12 +32,12 @@ class PCF8575
 {
 public:
   // deviceAddress base = 0x20 + depends on address bits
-  explicit PCF8575(const uint8_t deviceAddress, TwoWire *wire = &Wire);
+  explicit PCF8575(const uint8_t deviceAddress = 0x20, TwoWire *wire = &Wire);
 
 #if defined (ESP8266) || defined(ESP32)
-  bool     begin(uint8_t sda, uint8_t scl, uint16_t val = PCF8575_INITIAL_VALUE);
+  bool     begin(uint8_t sda, uint8_t scl, uint16_t value = PCF8575_INITIAL_VALUE);
 #endif
-  bool     begin(uint16_t val = PCF8575_INITIAL_VALUE);
+  bool     begin(uint16_t value = PCF8575_INITIAL_VALUE);
   bool     isConnected();
 
 
@@ -90,3 +90,4 @@ class PCF8575
 
 
 // -- END OF FILE --
+
diff --git a/README.md b/README.md
index c57c655..b3a0355 100644
--- a/README.md
+++ b/README.md
@@ -51,10 +51,10 @@ the include of "pcf8575.h" to overrule the default value used with the
 
 ### Constructor
 
-- **PCF8575(uint8_t deviceAddress, TwoWire \*wire = &Wire)** Constructor with I2C device address,
-and optional the Wire interface as parameter.
-- **bool begin(uint8_t val = PCF8575_INITIAL_VALUE)** set the initial value for the pins and masks.
-- **bool begin(uint8_t sda, uint8_t scl, uint8_t val = PCF8575_INITIAL_VALUE)** idem, 
+- **PCF8575(uint8_t deviceAddress = 0x20, TwoWire \*wire = &Wire)** Constructor with the optional 
+I2C device address, default 0x20, and the optional Wire interface as parameter.
+- **bool begin(uint8_t value = PCF8575_INITIAL_VALUE)** set the initial value for the pins and masks.
+- **bool begin(uint8_t dataPin, uint8_t clockPin, uint8_t value = PCF8575_INITIAL_VALUE)** idem, 
 for the ESP32 where one can choose the I2C pins.
 - **bool isConnected()** checks if the address is visible on the I2C bus.
 - **bool setAddress(const uint8_t deviceAddress)** sets the device address after construction. 
@@ -132,3 +132,5 @@ See examples.
 
 - update documentation.
 - keep in sync with pcf8574 (as far as meaningful)
+- **value()** => **lastRead16()**  ??
+
diff --git a/examples/PCF8575_Wire2/PCF8575_Wire2.ino b/examples/PCF8575_Wire2/PCF8575_Wire2.ino
index c71c1bb..bf702f2 100644
--- a/examples/PCF8575_Wire2/PCF8575_Wire2.ino
+++ b/examples/PCF8575_Wire2/PCF8575_Wire2.ino
@@ -2,15 +2,15 @@
 //    FILE: PCF8575_Wire2.ino
 //  AUTHOR: Rob Tillaart
 //    DATE: 2021-01-03
-//
-// PUPROSE: demo 
-//
+// PUPROSE: demo
+
 
 #include "PCF8575.h"
 
 // adjust addresses if needed
 PCF8575 PCF(0x39, &Wire2);
 
+
 void setup()
 {
   Serial.begin(115200);
@@ -34,6 +34,7 @@ void setup()
   delay(1000);
 }
 
+
 void loop()
 {
   Serial.println("HLT");
@@ -46,6 +47,7 @@ void loop()
   }
 }
 
+
 void doHigh()
 {
   PCF.write(4, HIGH);
@@ -54,6 +56,7 @@ void doHigh()
   Serial.println(x, HEX);
 }
 
+
 void doLow()
 {
   PCF.write(4, LOW);
@@ -62,6 +65,7 @@ void doLow()
   Serial.println(x, HEX);
 }
 
+
 void doToggle()
 {
   PCF.toggle(4);
@@ -70,4 +74,6 @@ void doToggle()
   Serial.println(x, HEX);
 }
 
+
 // -- END OF FILE --
+
diff --git a/examples/PCF8575_array/PCF8575_array.ino b/examples/PCF8575_array/PCF8575_array.ino
index 31f1d3e..12ac3df 100644
--- a/examples/PCF8575_array/PCF8575_array.ino
+++ b/examples/PCF8575_array/PCF8575_array.ino
@@ -3,7 +3,7 @@
 //  AUTHOR: Rob Tillaart
 //    DATE: 2021-12-13
 // PUPROSE: demo array of PCF - not tested
-//
+
 
 #include "PCF8575.h"
 
@@ -28,6 +28,7 @@ void setup()
   }
 }
 
+
 void loop()
 {
   for (int i = 0; i < 3; i++)
@@ -52,3 +53,4 @@ void loop()
 
 
 // -- END OF FILE --
+
diff --git a/examples/PCF8575_interrupt/PCF8575_interrupt.ino b/examples/PCF8575_interrupt/PCF8575_interrupt.ino
index ad1df70..ec70bad 100644
--- a/examples/PCF8575_interrupt/PCF8575_interrupt.ino
+++ b/examples/PCF8575_interrupt/PCF8575_interrupt.ino
@@ -4,18 +4,19 @@
 //    DATE: 2021-01-03
 // PUPROSE: test PCF8575 library
 //
-
 // TEST SETUP
-// Connect INT pin of the PCF8575 to UNO pin 2
+//  Connect INT pin of the PCF8575 to UNO pin 2
 //
-// (from figure 4 datasheet
-// Place a pull up resistor 4K7 between pin and 5V
-// Place a capacitor 10-400pF between pin and GND
+//  (from figure 4 datasheet
+//  Place a pull up resistor 4K7 between pin and 5V
+//  Place a capacitor 10-400 pF between pin and GND
+
 
 #include "PCF8575.h"
 
 PCF8575 PCF(0x38);
 
+
 ////////////////////////////////////
 //
 // INTERRUPT ROUTINE + FLAG
@@ -47,6 +48,7 @@ void setup()
   attachInterrupt(digitalPinToInterrupt(IRQPIN), pcf_irq, FALLING);
 }
 
+
 void loop()
 {
   uint32_t now = millis();
@@ -64,4 +66,6 @@ void loop()
   delay(10);
 }
 
+
 // -- END OF FILE --
+
diff --git a/examples/PCF8575_isConnected/PCF8575_isConnected.ino b/examples/PCF8575_isConnected/PCF8575_isConnected.ino
index 0975e42..8c564a0 100644
--- a/examples/PCF8575_isConnected/PCF8575_isConnected.ino
+++ b/examples/PCF8575_isConnected/PCF8575_isConnected.ino
@@ -2,15 +2,15 @@
 //    FILE: PCF8575_isConnected.ino
 //  AUTHOR: Rob Tillaart
 //    DATE: 2021-01-03
-//
-// PUPROSE: demo 
-//
+// PUPROSE: demo device detection
+
 
 #include "PCF8575.h"
 
 // adjust addresses if needed
 PCF8575 PCF(0x39);
 
+
 void setup()
 {
   Serial.begin(115200);
@@ -32,8 +32,11 @@ void setup()
   }
 }
 
+
 void loop()
 {
 }
 
+
 // -- END OF FILE --
+
diff --git a/examples/PCF8575_performance/PCF8575_performance.ino b/examples/PCF8575_performance/PCF8575_performance.ino
index 1e27a30..a3b500b 100644
--- a/examples/PCF8575_performance/PCF8575_performance.ino
+++ b/examples/PCF8575_performance/PCF8575_performance.ino
@@ -2,9 +2,9 @@
 //    FILE: PCF8575_performance.ino
 //  AUTHOR: Rob Tillaart
 //    DATE: 2021-01-24
-//
 // PUPROSE: test PCF8575 library
 
+
 #include "PCF8575.h"
 
 PCF8575 PCF(0x38);
@@ -13,6 +13,7 @@ uint32_t start, stop;
 
 volatile uint16_t x;
 
+
 void setup()
 {
   Serial.begin(115200);
@@ -41,10 +42,13 @@ void setup()
     Serial.println(stop - start);
     delay(1000);
   }
-
 }
 
+
 void loop()
 {
-
 }
+
+
+// -- END OF FILE --
+
diff --git a/examples/PCF8575_test/PCF8575_test.ino b/examples/PCF8575_test/PCF8575_test.ino
index 6a8cb2e..cfa4281 100644
--- a/examples/PCF8575_test/PCF8575_test.ino
+++ b/examples/PCF8575_test/PCF8575_test.ino
@@ -5,17 +5,19 @@
 // PUPROSE: test PCF8575 library
 //     URL: https://github.com/RobTillaart/PCF8575
 
+
 #include "PCF8575.h"
 
 PCF8575 PCF(0x38);
 
+
 void setup()
 {
   Serial.begin(115200);
   Serial.println(__FILE__);
   Serial.print("PCF8575_test version: ");
   Serial.println(PCF8575_LIB_VERSION);
-  
+
   PCF.begin();
 
   uint16_t x = PCF.read16();
@@ -24,6 +26,7 @@ void setup()
   delay(1000);
 }
 
+
 void loop()
 {
   Serial.println("HLT");
@@ -36,6 +39,7 @@ void loop()
   }
 }
 
+
 void doHigh()
 {
   PCF.write(4, HIGH);
@@ -44,6 +48,7 @@ void doHigh()
   printHex(x);
 }
 
+
 void doLow()
 {
   PCF.write(4, LOW);
@@ -52,6 +57,7 @@ void doLow()
   printHex(x);
 }
 
+
 void doToggle()
 {
   PCF.toggle(4);
@@ -69,4 +75,6 @@ void printHex(uint16_t x)
   Serial.println(x, HEX);
 }
 
+
 // -- END OF FILE --
+
diff --git a/examples/PCF8575_test1/PCF8575_test1.ino b/examples/PCF8575_test1/PCF8575_test1.ino
index 5aa0bdd..bef1d61 100644
--- a/examples/PCF8575_test1/PCF8575_test1.ino
+++ b/examples/PCF8575_test1/PCF8575_test1.ino
@@ -2,9 +2,8 @@
 //    FILE: pcf8575_test.ino
 //  AUTHOR: Rob Tillaart
 //    DATE: 2021-01-03
-//
 // PUPROSE: demo
-//
+
 
 #include "PCF8575.h"
 
@@ -12,6 +11,7 @@
 PCF8575 PCF_38(0x38);  // add switches to lines  (used as input)
 PCF8575 PCF_39(0x39);  // add leds to lines      (used as output)
 
+
 void setup()
 {
   Serial.begin(115200);
@@ -62,6 +62,7 @@ void setup()
   }
 }
 
+
 void loop()
 {
   // echos the lines
@@ -70,4 +71,6 @@ void loop()
   delay(100);
 }
 
-// END OF FILE
+
+// -- END OF FILE --
+
diff --git a/examples/PCF8575_test2/PCF8575_test2.ino b/examples/PCF8575_test2/PCF8575_test2.ino
index a1c2714..9294cdb 100644
--- a/examples/PCF8575_test2/PCF8575_test2.ino
+++ b/examples/PCF8575_test2/PCF8575_test2.ino
@@ -2,14 +2,14 @@
 //    FILE: pcf8575_test2.ino
 //  AUTHOR: Rob Tillaart
 //    DATE: 2021-01-03
-//
 // PUPROSE: demo rotateLeft, -Right and toggleMask
-//
+
 
 #include "PCF8575.h"
 
 // adjust addresses if needed
-PCF8575 PCF(0x39);  // add leds to lines      (used as output)
+PCF8575 PCF(0x39);  // add LEDs to lines      (used as output)
+
 
 void setup()
 {
@@ -61,8 +61,11 @@ void setup()
   }
 }
 
+
 void loop()
 {
 }
 
+
 // -- END OF FILE --
+
diff --git a/keywords.txt b/keywords.txt
index af1d6f3..8ccbe43 100644
--- a/keywords.txt
+++ b/keywords.txt
@@ -1,8 +1,10 @@
 # Syntax Colouring Map For PCF8575
 
+
 # Data types (KEYWORD1)
 PCF8575	KEYWORD1
 
+
 # Methods and Functions (KEYWORD2)
 begin	KEYWORD2
 isConnected	KEYWORD2
@@ -32,5 +34,11 @@ reverse	KEYWORD2
 
 lastError	KEYWORD2
 
+
 # Constants (LITERAL1)
+PCF8575_LIB_VERSION	LITERAL1
+PCF8575_INITIAL_VALUE	LITERAL1
+PCF8575_OK	LITERAL1
+PCF8575_PIN_ERROR	LITERAL1
+PCF8575_I2C_ERROR	LITERAL1
 
diff --git a/library.json b/library.json
index acfb895..962044c 100644
--- a/library.json
+++ b/library.json
@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/PCF8575.git"
   },
-  "version": "0.1.3",
+  "version": "0.1.4",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*",
diff --git a/library.properties b/library.properties
index 7c8c55b..f98d13c 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=PCF8575
-version=0.1.3
+version=0.1.4
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=Arduino library for PCF8575 - 16 channel I2C IO expander
diff --git a/test/unit_test_001.cpp b/test/unit_test_001.cpp
index 1b7d1dd..b0b16fa 100644
--- a/test/unit_test_001.cpp
+++ b/test/unit_test_001.cpp
@@ -42,16 +42,26 @@ PCF8575 PCF(0x38);
 
 unittest_setup()
 {
+  fprintf(stderr, "PCF8575_LIB_VERSION: %s\n", (char *) PCF8575_LIB_VERSION);
 }
 
+
 unittest_teardown()
 {
 }
 
-unittest(test_begin)
+
+unittest(test_constants)
 {
-  fprintf(stderr, "VERSION: %s\n", PCF8575_LIB_VERSION);
+  assertEqual(PCF8575_INITIAL_VALUE, 0xFFFF);
+  assertEqual(PCF8575_OK           , 0x00);
+  assertEqual(PCF8575_PIN_ERROR    , 0x81);
+  assertEqual(PCF8575_I2C_ERROR    , 0x82);
+}
 
+
+unittest(test_begin)
+{
   PCF8575 PCF(0x38);
 
   PCF.begin();