diff --git a/PCF8574.cpp b/PCF8574.cpp
index 2bb92c7..99ffc5a 100644
--- a/PCF8574.cpp
+++ b/PCF8574.cpp
@@ -53,7 +53,7 @@ PCF8574::PCF8574(uint8_t address, uint8_t interruptPin,  void (*interruptFunctio
 	_usingInterrupt = true;
 };
 
-#ifndef __AVR
+#if !defined(__AVR) && !defined(__STM32F1__)
 	/**
 	 * Constructor
 	 * @param address: i2c address
@@ -156,7 +156,7 @@ PCF8574::PCF8574(uint8_t address, uint8_t interruptPin,  void (*interruptFunctio
  * wake up i2c controller
  */
 void PCF8574::begin(){
-	#ifndef __AVR
+	#if !defined(__AVR) && !defined(__STM32F1__)
 		_wire->begin(_sda, _scl);
 	#else
 	//			Default pin for AVR some problem on software emulation
@@ -165,7 +165,7 @@ void PCF8574::begin(){
 		_wire->begin();
 	#endif
 
-	// Che if there are pins to set low
+	// Check if there are pins to set low
 	if (writeMode>0 || readMode>0){
 		DEBUG_PRINTLN("Set write mode");
 		_wire->beginTransmission(_address);
diff --git a/PCF8574.h b/PCF8574.h
index a11544b..65f355a 100644
--- a/PCF8574.h
+++ b/PCF8574.h
@@ -83,7 +83,7 @@ public:
 	PCF8574(uint8_t address);
 	PCF8574(uint8_t address, uint8_t interruptPin,  void (*interruptFunction)() );
 
-#ifndef __AVR
+#if !defined(__AVR) && !defined(__STM32F1__)
 	PCF8574(uint8_t address, uint8_t sda, uint8_t scl);
 	PCF8574(uint8_t address, uint8_t sda, uint8_t scl, uint8_t interruptPin,  void (*interruptFunction)());
 #endif
@@ -123,8 +123,14 @@ public:
 
 private:
 	uint8_t _address;
-	uint8_t _sda = SDA;
-	uint8_t _scl = SCL;
+
+	#if defined(__AVR) || defined(__STM32F1__)
+		uint8_t _sda;
+		uint8_t _scl;
+	#else
+		uint8_t _sda = SDA;
+		uint8_t _scl = SCL;
+	#endif
 
 	TwoWire *_wire;
 
diff --git a/README.md b/README.md
index 2d6665b..9bb3c7e 100644
--- a/README.md
+++ b/README.md
@@ -1,4 +1,8 @@
+<<<<<<< HEAD
 Additional information and document update here on my site: [pcf8574 Article](https://www.mischianti.org/2019/01/02/pcf8574-i2c-digital-i-o-expander-fast-easy-usage/).
+=======
+You can find document update at www.mischianti.org
+>>>>>>> branch 'master' of https://github.com/xreef/PCF8574_library.git
 
 Library to use i2c analog IC with arduino and esp8266. Can read and write digital value with only 2 wire (perfect for ESP-01).