diff --git a/LICENSE b/LICENSE
index 39d07e3..c9bd779 100644
--- a/LICENSE
+++ b/LICENSE
@@ -1,6 +1,6 @@
 MIT License
 
-Copyright (c) 2013-2021 Rob Tillaart
+Copyright (c) 2013-2022 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/PCF8574.cpp b/PCF8574.cpp
index 533f21d..11d58c4 100644
--- a/PCF8574.cpp
+++ b/PCF8574.cpp
@@ -2,13 +2,14 @@
 //    FILE: PCF8574.cpp
 //  AUTHOR: Rob Tillaart
 //    DATE: 02-febr-2013
-// VERSION: 0.3.2
+// VERSION: 0.3.3
 // PURPOSE: Arduino library for PCF8574 - 8 channel I2C IO expander
 //     URL: https://github.com/RobTillaart/PCF8574
 //          http://forum.arduino.cc/index.php?topic=184800
 //
 //  HISTORY:
-//  
+//
+//  0.3.3   2021-12-23  update library.json, license, readme, minor edits
 //  0.3.2   2021-07-04  fix #25 add setAddress()
 //  0.3.1   2021-04-23  Fix for platformIO compatibility
 //  0.3.0   2021-01-03  multiWire support - inspired by mattbue - issue #14
@@ -20,9 +21,9 @@
 //          removed pre 1.0 support
 //          added begin(dsa, scl) for ESP32
 //          added reverse()
-//          
+//
 //  0.1.9   2017-02-27  fix warning about return in readButton8()
-//  0.1.08  2016-05-20  Merged work of Septillion 
+//  0.1.08  2016-05-20  Merged work of Septillion
 //          Fix/refactor ButtonRead8() - see https://github.com/RobTillaart/Arduino/issues/38
 //          missing begin() => mask parameter
 //  0.1.07  2016-05-02  (manually merged) Septillion
@@ -60,7 +61,7 @@ PCF8574::PCF8574(const uint8_t deviceAddress, TwoWire *wire)
 
 
 #if defined (ESP8266) || defined(ESP32)
-bool PCF8574::begin(uint8_t dataPin, uint8_t clockPin, uint8_t val)
+bool PCF8574::begin(uint8_t dataPin, uint8_t clockPin, uint8_t value)
 {
   _wire      = &Wire;
   if ((dataPin < 255) && (clockPin < 255))
@@ -70,17 +71,17 @@ bool PCF8574::begin(uint8_t dataPin, uint8_t clockPin, uint8_t val)
     _wire->begin();
   }
   if (! isConnected()) return false;
-  PCF8574::write8(val);
+  PCF8574::write8(value);
   return true;
 }
 #endif
 
 
-bool PCF8574::begin(uint8_t val)
+bool PCF8574::begin(uint8_t value)
 {
   _wire->begin();
   if (! isConnected()) return false;
-  PCF8574::write8(val);
+  PCF8574::write8(value);
   return true;
 }
 
@@ -105,11 +106,11 @@ uint8_t PCF8574::getAddress()
 }
 
 
-// removed _wire->beginTransmission(addr);
-// with  @100KHz -> 265 micros()
-// without @100KHz -> 132 micros()
-// without @400KHz -> 52 micros()
-// TODO @800KHz -> ??
+// removed _wire->beginTransmission(_address);
+// with    @100 KHz -> 265 micros()
+// without @100 KHz -> 132 micros()
+// without @400 KHz -> 52 micros()
+// TODO    @800 KHz -> ??
 uint8_t PCF8574::read8()
 {
   if (_wire->requestFrom(_address, (uint8_t)1) != 1)
@@ -253,10 +254,11 @@ uint8_t PCF8574::readButton(const uint8_t pin)
 
   uint8_t temp = _dataOut;
   PCF8574::write(pin, HIGH);
-  uint8_t rtn = PCF8574::read(pin);
+  uint8_t value = PCF8574::read(pin);
   PCF8574::write8(temp);
-  return rtn;
+  return value;
 }
 
 
 // -- END OF FILE --
+
diff --git a/PCF8574.h b/PCF8574.h
index ca91154..197b356 100644
--- a/PCF8574.h
+++ b/PCF8574.h
@@ -1,9 +1,9 @@
 #pragma once
 //
-//    FILE: PCF8574.H
+//    FILE: PCF8574.h
 //  AUTHOR: Rob Tillaart
 //    DATE: 02-febr-2013
-// VERSION: 0.3.2
+// VERSION: 0.3.3
 // PURPOSE: Arduino library for PCF8574 - 8 channel I2C IO expander
 //     URL: https://github.com/RobTillaart/PCF8574
 //          http://forum.arduino.cc/index.php?topic=184800
@@ -17,26 +17,26 @@
 #include "Wire.h"
 
 
-#define PCF8574_LIB_VERSION     (F("0.3.2"))
+#define PCF8574_LIB_VERSION         (F("0.3.3"))
 
 #ifndef PCF8574_INITIAL_VALUE
-#define PCF8574_INITIAL_VALUE    0xFF
+#define PCF8574_INITIAL_VALUE       0xFF
 #endif
 
-#define PCF8574_OK              0x00
-#define PCF8574_PIN_ERROR       0x81
-#define PCF8574_I2C_ERROR       0x82
+#define PCF8574_OK                  0x00
+#define PCF8574_PIN_ERROR           0x81
+#define PCF8574_I2C_ERROR           0x82
 
 
 class PCF8574
 {
 public:
-  explicit PCF8574(const uint8_t deviceAddress, TwoWire *wire = &Wire);
+  explicit PCF8574(const uint8_t deviceAddress = 0x20, TwoWire *wire = &Wire);
 
 #if defined (ESP8266) || defined(ESP32)
-  bool    begin(uint8_t sda, uint8_t scl, uint8_t val = PCF8574_INITIAL_VALUE);
+  bool    begin(uint8_t sda, uint8_t scl, uint8_t value = PCF8574_INITIAL_VALUE);
 #endif
-  bool    begin(uint8_t val = PCF8574_INITIAL_VALUE);
+  bool    begin(uint8_t value = PCF8574_INITIAL_VALUE);
   bool    isConnected();
 
 
@@ -89,3 +89,4 @@ class PCF8574
 
 
 // -- END OF FILE --
+
diff --git a/README.md b/README.md
index 2c4a93e..6a0b7c9 100644
--- a/README.md
+++ b/README.md
@@ -39,10 +39,10 @@ the include of "pcf8574.h" to overrule the default value used with the **begin()
 
 ### Constructor
 
-- **PCF8574(deviceAddress, TwoWire \*wire = &Wire)** Constructor with device address, 
-and optional the Wire interface as parameter.
-- **bool begin(uint8_t val = PCF8574_INITIAL_VALUE)** set the initial value for the pins and masks.
-- **bool begin(uint8_t sda, uint8_t scl, uint8_t val = PCF8574_INITIAL_VALUE)** idem, for the ESP32 where one can choose the I2C pins.
+- **PCF8574(uint8_t deviceAddress = 0x20, TwoWire \*wire = &Wire)** Constructor with optional device address, default 0x20, 
+and the optional Wire interface as parameter.
+- **bool begin(uint8_t value = PCF8574_INITIAL_VALUE)** set the initial value for the pins and masks.
+- **bool begin(uint8_t sda, uint8_t scl, uint8_t value = PCF8574_INITIAL_VALUE)** idem, for the ESP32 where one can choose the I2C pins.
 - **bool isConnected()** checks if the address set in the constructor or by **setAddress()** is visible on the I2C bus.
 - **bool setAddress(const uint8_t deviceAddress)** sets the device address after construction. 
 Can be used to switch between PCF8574 modules runtime. Note this corrupts internal buffered values, 
diff --git a/examples/PCF8574_Wire2/PCF8574_Wire2.ino b/examples/PCF8574_Wire2/PCF8574_Wire2.ino
index 9ab3a5b..73863e5 100644
--- a/examples/PCF8574_Wire2/PCF8574_Wire2.ino
+++ b/examples/PCF8574_Wire2/PCF8574_Wire2.ino
@@ -2,8 +2,7 @@
 //    FILE: PCF8574_Wire2.ino
 //  AUTHOR: Rob Tillaart
 //    DATE: 2016-04-30
-// PUPROSE: demo 
-//
+// PUPROSE: demo
 
 
 #include "PCF8574.h"
diff --git a/examples/PCF8574_interrupt/PCF8574_interrupt.ino b/examples/PCF8574_interrupt/PCF8574_interrupt.ino
index 8b7bb44..b215162 100644
--- a/examples/PCF8574_interrupt/PCF8574_interrupt.ino
+++ b/examples/PCF8574_interrupt/PCF8574_interrupt.ino
@@ -4,13 +4,12 @@
 //    DATE: 2020-12-07
 // PUPROSE: test PCF8574 library
 //
-
 // TEST SETUP
-// Connect INT pin of the PCF8574 to UNO pin 2
+//   Connect INT pin of the PCF8574 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 10-400pF between pin and GND
 
 
 #include "PCF8574.h"
@@ -69,3 +68,4 @@ void loop()
 
 
 // -- END OF FILE --
+
diff --git a/examples/PCF8574_isConnected/PCF8574_isConnected.ino b/examples/PCF8574_isConnected/PCF8574_isConnected.ino
index 37de345..8bdf5d2 100644
--- a/examples/PCF8574_isConnected/PCF8574_isConnected.ino
+++ b/examples/PCF8574_isConnected/PCF8574_isConnected.ino
@@ -3,7 +3,6 @@
 //  AUTHOR: Rob Tillaart
 //    DATE: 2021-01-03
 // PUPROSE: demo isConnected function
-//
 
 
 #include "PCF8574.h"
@@ -40,3 +39,4 @@ void loop()
 
 
 // -- END OF FILE --
+
diff --git a/examples/PCF8574_rotaryEncoder/PCF8574_rotaryEncoder.ino b/examples/PCF8574_rotaryEncoder/PCF8574_rotaryEncoder.ino
index cd204f5..8c1d729 100644
--- a/examples/PCF8574_rotaryEncoder/PCF8574_rotaryEncoder.ino
+++ b/examples/PCF8574_rotaryEncoder/PCF8574_rotaryEncoder.ino
@@ -2,9 +2,8 @@
 //    FILE: PCF8574_rotaryEncoder.ino
 //  AUTHOR: Rob Tillaart
 //    DATE: 2021-05-08
-//
 // PUPROSE: demo PCF8574 as rotary encoder reader.
-
+//
 //
 //  RotaryEncoder    PCF8574      UNO
 //  --------------------------------------
@@ -132,3 +131,4 @@ void updateRotaryDecoder()
 
 
 // -- END OF FILE --
+
diff --git a/examples/PCF8574_test/PCF8574_test.ino b/examples/PCF8574_test/PCF8574_test.ino
index 0f13e17..742dab9 100644
--- a/examples/PCF8574_test/PCF8574_test.ino
+++ b/examples/PCF8574_test/PCF8574_test.ino
@@ -1,10 +1,8 @@
-
 //
 //    FILE: PCF8574_test.ino
 //  AUTHOR: Rob Tillaart
 //    DATE: 7-febr-2013
 // PUPROSE: test PCF8574 library
-//
 
 
 #include "PCF8574.h"
diff --git a/examples/PCF8574_test1/PCF8574_test1.ino b/examples/PCF8574_test1/PCF8574_test1.ino
index f092f7c..09a9f49 100644
--- a/examples/PCF8574_test1/PCF8574_test1.ino
+++ b/examples/PCF8574_test1/PCF8574_test1.ino
@@ -1,9 +1,9 @@
 //
-//    FILE: pcf8574_test.ino
+//    FILE: PCF8574_test.ino
 //  AUTHOR: Rob Tillaart
 //    DATE: 27-08-2013
 // PUPROSE: demo
-//
+
 
 #include "PCF8574.h"
 
diff --git a/examples/PCF8574_test2/PCF8574_test2.ino b/examples/PCF8574_test2/PCF8574_test2.ino
index 783d4f7..2013b74 100644
--- a/examples/PCF8574_test2/PCF8574_test2.ino
+++ b/examples/PCF8574_test2/PCF8574_test2.ino
@@ -3,7 +3,6 @@
 //  AUTHOR: Rob Tillaart
 //    DATE: 2016-04-30
 // PUPROSE: demo rotateLeft, -Right and toggleMask
-//
 
 
 #include "PCF8574.h"
diff --git a/keywords.txt b/keywords.txt
index c8f523c..f98d901 100644
--- a/keywords.txt
+++ b/keywords.txt
@@ -37,4 +37,5 @@ lastError	KEYWORD2
 PCF8574_LIB_VERSION	LITERAL1
 PCF8574_OK	LITERAL1
 PCF8574_PIN_ERROR	LITERAL1
-PCF8574_I2C_ERROR	LITERAL1
\ No newline at end of file
+PCF8574_I2C_ERROR	LITERAL1
+
diff --git a/library.json b/library.json
index 3ddbf25..8529d7e 100644
--- a/library.json
+++ b/library.json
@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/PCF8574.git"
   },
-  "version": "0.3.2",
+  "version": "0.3.3",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*",
diff --git a/library.properties b/library.properties
index d72c2d9..8973a48 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=PCF8574
-version=0.3.2
+version=0.3.3
 author=Rob Tillaart <rob.tillaart@gmail.com>
 maintainer=Rob Tillaart <rob.tillaart@gmail.com>
 sentence=Arduino library for PCF8574 - 8 channel I2C IO expander
diff --git a/test/unit_test_001.cpp b/test/unit_test_001.cpp
index 3139a81..af58a29 100644
--- a/test/unit_test_001.cpp
+++ b/test/unit_test_001.cpp
@@ -42,16 +42,17 @@ PCF8574 PCF(0x38);
 
 unittest_setup()
 {
+  fprintf(stderr, "PCF8574_LIB_VERSION: %s\n", (char *) PCF8574_LIB_VERSION);
 }
 
+
 unittest_teardown()
 {
 }
 
+
 unittest(test_begin)
 {
-  fprintf(stderr, "VERSION: %s\n", PCF8574_LIB_VERSION);
-
   PCF8574 PCF(0x38);
 
   PCF.begin();
@@ -103,4 +104,5 @@ unittest(test_address)
 
 unittest_main()
 
+
 // --------