diff --git a/.github/workflows/arduino-lint.yml b/.github/workflows/arduino-lint.yml
index b2ca058..8a26f14 100644
--- a/.github/workflows/arduino-lint.yml
+++ b/.github/workflows/arduino-lint.yml
@@ -6,7 +6,7 @@ jobs:
   lint:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: arduino/arduino-lint-action@v1
         with:
           library-manager: update
diff --git a/.github/workflows/arduino_test_runner.yml b/.github/workflows/arduino_test_runner.yml
index 096b975..fadfa90 100644
--- a/.github/workflows/arduino_test_runner.yml
+++ b/.github/workflows/arduino_test_runner.yml
@@ -8,7 +8,7 @@ jobs:
     runs-on: ubuntu-latest
 
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - uses: ruby/setup-ruby@v1
         with:
           ruby-version: 2.6
diff --git a/.github/workflows/jsoncheck.yml b/.github/workflows/jsoncheck.yml
index 04603d0..37a1129 100644
--- a/.github/workflows/jsoncheck.yml
+++ b/.github/workflows/jsoncheck.yml
@@ -10,7 +10,7 @@ jobs:
   test:
     runs-on: ubuntu-latest
     steps:
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@v3
       - name: json-syntax-check
         uses: limitusus/json-syntax-check@v1
         with:
diff --git a/CHANGELOG.md b/CHANGELOG.md
index f1bd3d9..a5a74ca 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -6,6 +6,16 @@ The format is based on [Keep a Changelog](http://keepachangelog.com/)
 and this project adheres to [Semantic Versioning](http://semver.org/).
 
 
+## [0.1.4] - 2022-12-29
+- Fix #7 missing public:
+- add unit test for TCA9535 constructor
+- add examples for TCA9535
+- update examples
+- add **getAddress()** (debugging)
+- update readme.md
+- update GitHub actions -> v3
+
+
 ## [0.1.3] - 2022-11-25
 - Add RP2040 support to build-CI.
 - Add CHANGELOG.md
diff --git a/README.md b/README.md
index 48983a0..4137f20 100644
--- a/README.md
+++ b/README.md
@@ -29,24 +29,35 @@ input and not driven. This reduces power consumption when the I/O is held low._
 There is a TCA9535 class which is a (convenience) wrapper around the TCA9555 class. 
 This allows one to create TCA9535 objects. 
 
+## Hardware
+
+#### I2C addresses
+
+Allowed addresses are 0x20..0x27. to be set with pin A0, A1, A2.
+
 
 ## Interface
 
 Check the datasheet for details
 
+```cpp
+#include "TCA9555.h"
+```
 
-### Constructor
+#### Constructor
 
-- **TCA9555(uint8_t address, TwoWire \*wire = &Wire)** constructor, with default Wire interface. Can be overruled with Wire0..WireN.
+- **TCA9555(uint8_t address, TwoWire \*wire = &Wire)** constructor, with default Wire interface. 
+Can be overruled with Wire0..WireN.
 - **TCA9535(uint8_t address, TwoWire \*wire = &Wire)** idem.
 
 
 - **bool begin()** for UNO, returns true if successful.
 - **bool begin(uint8_t sda, uint8_t scl)** for ESP32, returns true if successful.
 - **bool isConnected()** returns true if connected, false otherwise.
+- **uint8_t getAddress()** returns set address, (debugging).
 
 
-### 1 pin interface
+#### 1 pin interface
 
 - **bool pinMode(uint8_t pin, uint8_t mode)** idem.
 - **bool digitalWrite(uint8_t pin, uint8_t value)** pin = 0..15, value = LOW(0) HIGH (!0), returns true if successful.
@@ -55,7 +66,7 @@ Check the datasheet for details
 - **uint8_t getPolarity(uint8_t pin)** returns 1 if a pin is inverted.
 
 
-### 8 pin interface
+#### 8 pin interface
 
 port = 0..1  
 mask = 0..255
@@ -68,7 +79,7 @@ Especially useful if one needs to trigger multiple pins at the exact same time.
 - **uint8_t getPolarity(uint8_t port)** returns a mask with a 1 for every INPUT pin that is inverted.
 
 
-### 16 pin interface
+#### 16 pin interface
 
 Be aware that the 16 pins interface does two calls to the 8 pins interface. 
 So it is impossible to switch pins from the 2 groups of 8 at exactly the same time 
@@ -82,20 +93,20 @@ Returns true upon success.
 - **uint16_t getPolarity()** returns a mask of 16 bits with a 1 for every INPUT pin that is inverted.
 
 
-### Error codes
+#### Error codes
 
 - **int lastError()** Above functions set an error flag that can be read with this function. 
 Reading it will reset the flag to **TCA9555_OK**.
 
 
-| DESCRIPTION          | VALUE |
-|:---------------------|:-----:|
-| TCA9555_OK           |  0x00 |
-| TCA9555_PIN_ERROR    |  0x81 |
-| TCA9555_I2C_ERROR    |  0x82 |
-| TCA9555_VALUE_ERROR  |  0x83 |
-| TCA9555_PORT_ERROR   |  0x84 |
-| TCA9555_INVALID_READ |  -100 |
+|  Description           |  Value  |
+|:-----------------------|:-------:|
+|  TCA9555_OK            |  0x00   |
+|  TCA9555_PIN_ERROR     |  0x81   |
+|  TCA9555_I2C_ERROR     |  0x82   |
+|  TCA9555_VALUE_ERROR   |  0x83   |
+|  TCA9555_PORT_ERROR    |  0x84   |
+|  TCA9555_INVALID_READ  |  -100   |
 
 
 ## Operation
@@ -107,17 +118,31 @@ See examples
 
 
 #### Must
+
 - buy TCA9555 / TCA9535
 - test all functionality (initial version is written with no hardware around)
 
+
 #### Should
-- INPUT_PULLUP mappen op INPUT (pinMode ?)
+
+- investigate map INPUT_PULLUP on INPUT (pinMode ?)
 - investigate internal pull up etc.
-- add TCA9535 error codes
 - investigate TCA9535 differences
-  - elaborate derived class 
+  - pull up resistors
+  - elaborate derived class
+- add **getType()** to distinguish derived classes.
+  - int or uint8_t => 4 or 2 digits, define?
+  - or even a string (no)?
+  - constructor
+
 
 #### Could
+
 - rethink class hierarchy
+  -5535 has less functions so should be base class?
+- valid address range?
 
 
+#### Wont (unless)
+- add TCA9535 error codes
+  - better reuse them?
diff --git a/TCA9555.cpp b/TCA9555.cpp
index 9ebe4cd..2d0e5ab 100644
--- a/TCA9555.cpp
+++ b/TCA9555.cpp
@@ -1,7 +1,7 @@
 //
 //    FILE: TCA9555.cpp
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.3
+// VERSION: 0.1.4
 // PURPOSE: Arduino library for I2C TCA9555 16 channel port expander
 //    DATE: 2021-06-09
 //     URL: https://github.com/RobTillaart/TCA9555
@@ -55,6 +55,12 @@ bool TCA9555::isConnected()
 }
 
 
+uint8_t TCA9555::getAddress()
+{
+  return _address;
+}
+
+
 //////////////////////////////////////////////////////////
 //
 //  1 PIN INTERFACE
diff --git a/TCA9555.h b/TCA9555.h
index b8b0b05..5eb59c8 100644
--- a/TCA9555.h
+++ b/TCA9555.h
@@ -2,7 +2,7 @@
 //
 //    FILE: TCA9555.h
 //  AUTHOR: Rob Tillaart
-// VERSION: 0.1.3
+// VERSION: 0.1.4
 // PURPOSE: Arduino library for I2C TCA9555 16 channel port expander
 //    DATE: 2021-06-09
 //     URL: https://github.com/RobTillaart/TCA9555
@@ -12,7 +12,7 @@
 #include "Wire.h"
 
 
-#define TCA9555_LIB_VERSION               (F("0.1.3"))
+#define TCA9555_LIB_VERSION               (F("0.1.4"))
 
 #define TCA9555_OK                        0x00
 #define TCA9555_PIN_ERROR                 0x81
@@ -34,6 +34,7 @@ class TCA9555
 #endif
   bool     begin();
   bool     isConnected();
+  uint8_t  getAddress();
 
 
   //  1 PIN INTERFACE
@@ -87,6 +88,7 @@ class TCA9555
 //
 class TCA9535 : public TCA9555
 {
+public:
   TCA9535(uint8_t address, TwoWire *wire = &Wire);
 };
 
diff --git a/examples/TCA9535_digitalRead/TCA9535_digitalRead.ino b/examples/TCA9535_digitalRead/TCA9535_digitalRead.ino
new file mode 100644
index 0000000..1692fb3
--- /dev/null
+++ b/examples/TCA9535_digitalRead/TCA9535_digitalRead.ino
@@ -0,0 +1,41 @@
+//
+//    FILE: TCA9535_digitalRead.ino
+//  AUTHOR: Rob Tillaart
+// PUPROSE: test TCA9555 library
+//     URL: https://github.com/RobTillaart/TCA9555
+
+
+#include "Wire.h"
+#include "TCA9555.h"
+
+
+TCA9535 TCA(0x27);
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.print("TCA9555_LIB_VERSION: ");
+  Serial.println(TCA9555_LIB_VERSION);
+
+  Wire.begin();
+  TCA.begin();
+
+  Serial.println("TEST digitalRead(pin)");
+  for (int pin = 0; pin < 16; pin++)
+  {
+    int val = TCA.digitalRead(pin);
+    Serial.print(val);
+    Serial.print('\t');
+  }
+  Serial.println(); 
+}
+
+
+void loop()
+{
+}
+
+
+// -- END OF FILE --
+
diff --git a/examples/TCA9535_digitalWrite/TCA9535_digitalWrite.ino b/examples/TCA9535_digitalWrite/TCA9535_digitalWrite.ino
new file mode 100644
index 0000000..86a0986
--- /dev/null
+++ b/examples/TCA9535_digitalWrite/TCA9535_digitalWrite.ino
@@ -0,0 +1,65 @@
+//
+//    FILE: TCA9535_digitalWrite.ino
+//  AUTHOR: Rob Tillaart
+// PUPROSE: test TCA9555 library - TCA9535 derived class
+//     URL: https://github.com/RobTillaart/TCA9555
+
+
+#include "Wire.h"
+#include "TCA9555.h"
+
+
+TCA9535 TCA(0x27);
+
+
+void setup()
+{
+  Serial.begin(115200);
+  Serial.print("TCA9555_LIB_VERSION: ");
+  Serial.println(TCA9555_LIB_VERSION);
+
+  Wire.begin();
+  TCA.begin();
+
+  Wire.setClock(50);
+
+  Serial.println("TEST digitalWrite(0)");
+  for (int i = 0; i < 16; i++)
+  {
+    TCA.digitalWrite(0, i % 2);  // alternating HIGH/LOW
+    Serial.print(i % 2);
+    Serial.print('\t');
+    delay(250);
+  }
+  Serial.println();
+  Serial.println();
+
+  Serial.println("TEST digitalWrite(pin)");
+  for (int pin = 0; pin < 16; pin++)
+  {
+    TCA.digitalWrite(pin, 1 - pin % 2); // alternating HIGH/LOW
+    Serial.print(1 - pin % 2);
+    Serial.print('\t');
+  }
+  Serial.println();
+  Serial.println();
+
+  Serial.println("TEST read back");
+
+  for (int pin = 0; pin < 16; pin++)
+  {
+    int val = TCA.digitalRead(pin);
+    Serial.print(val);
+    Serial.print('\t');
+  }
+  Serial.println();
+  Serial.println();
+}
+
+
+void loop()
+{
+}
+
+
+// -- END OF FILE --
diff --git a/examples/TCA9555_digitalRead/TCA9555_digitalRead.ino b/examples/TCA9555_digitalRead/TCA9555_digitalRead.ino
index 03916af..71b64b7 100644
--- a/examples/TCA9555_digitalRead/TCA9555_digitalRead.ino
+++ b/examples/TCA9555_digitalRead/TCA9555_digitalRead.ino
@@ -1,12 +1,12 @@
 //
 //    FILE: TCA9555_digitalRead.ino
 //  AUTHOR: Rob Tillaart
-///    DATE: 2021-06-09
 // PUPROSE: test TCA9555 library
+//     URL: https://github.com/RobTillaart/TCA9555
 
 
-#include "TCA9555.h"
 #include "Wire.h"
+#include "TCA9555.h"
 
 
 TCA9555 TCA(0x27);
diff --git a/examples/TCA9555_digitalWrite/TCA9555_digitalWrite.ino b/examples/TCA9555_digitalWrite/TCA9555_digitalWrite.ino
index 1498e99..a4492b1 100644
--- a/examples/TCA9555_digitalWrite/TCA9555_digitalWrite.ino
+++ b/examples/TCA9555_digitalWrite/TCA9555_digitalWrite.ino
@@ -1,12 +1,12 @@
 //
 //    FILE: TCA9555_digitalWrite.ino
 //  AUTHOR: Rob Tillaart
-//    DATE: 2021-06-09
 // PUPROSE: test TCA9555 library
+//     URL: https://github.com/RobTillaart/TCA9555
 
 
-#include "TCA9555.h"
 #include "Wire.h"
+#include "TCA9555.h"
 
 
 TCA9555 TCA(0x27);
diff --git a/examples/TCA9555_setPolarity/TCA9555_setPolarity.ino b/examples/TCA9555_setPolarity/TCA9555_setPolarity.ino
index 9c68141..099d5ef 100644
--- a/examples/TCA9555_setPolarity/TCA9555_setPolarity.ino
+++ b/examples/TCA9555_setPolarity/TCA9555_setPolarity.ino
@@ -1,12 +1,12 @@
 //
 //    FILE: TCA9555_setPolarity.ino
 //  AUTHOR: Rob Tillaart
-///    DATE: 2021-06-09
 // PUPROSE: test TCA9555 library
+//     URL: https://github.com/RobTillaart/TCA9555
 
 
-#include "TCA9555.h"
 #include "Wire.h"
+#include "TCA9555.h"
 
 
 TCA9555 TCA(0x27);
diff --git a/library.json b/library.json
index 7ca842a..7f7ae8c 100644
--- a/library.json
+++ b/library.json
@@ -15,7 +15,7 @@
     "type": "git",
     "url": "https://github.com/RobTillaart/TCA9555.git"
   },
-  "version": "0.1.3",
+  "version": "0.1.4",
   "license": "MIT",
   "frameworks": "arduino",
   "platforms": "*",
diff --git a/library.properties b/library.properties
index 7178c93..5ecd9d4 100644
--- a/library.properties
+++ b/library.properties
@@ -1,5 +1,5 @@
 name=TCA9555
-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 I2C TCA9555 16 channel port expander - 16 IO-lines
diff --git a/test/unit_test_001.cpp b/test/unit_test_001.cpp
index c062d31..030d556 100644
--- a/test/unit_test_001.cpp
+++ b/test/unit_test_001.cpp
@@ -48,7 +48,7 @@ unittest_teardown()
 }
 
 
-unittest(test_constructor)
+unittest(test_constructor_TCA9555)
 {
   TCA9555 TCA(0x22);
 
@@ -57,6 +57,15 @@ unittest(test_constructor)
 }
 
 
+unittest(test_constructor_TCA9535)
+{
+  TCA9535 TCA(0x22);
+
+  assertTrue(TCA.begin());
+  assertTrue(TCA.isConnected());
+}
+
+
 unittest(test_constants)
 {
   assertEqual(0x00, TCA9555_OK);